{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/products/microsoft-defender-xdr/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Sysmon Registry Events","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["port-forwarding","registry-modification","command-and-control","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers may configure port forwarding rules to bypass network segmentation restrictions, effectively using the compromised host as a jump box to access previously unreachable systems. This involves modifying the registry to redirect incoming TCP connections from a local port to another port or a remote computer. The technique is typically employed post-compromise to facilitate lateral movement and maintain unauthorized access within the network. This activity is detected by monitoring changes to the \u003ccode\u003eHKLM\\SYSTEM\\*ControlSet*\\Services\\PortProxy\\v4tov4\\\u003c/code\u003e registry subkeys.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the target system through an exploit or compromised credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker executes a command-line interface (e.g., \u003ccode\u003ecmd.exe\u003c/code\u003e or \u003ccode\u003epowershell.exe\u003c/code\u003e) with administrative privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003ereg.exe\u003c/code\u003e or PowerShell\u0026rsquo;s \u003ccode\u003eSet-ItemProperty\u003c/code\u003e cmdlet to modify the \u003ccode\u003eHKLM\\SYSTEM\\CurrentControlSet\\Services\\PortProxy\\v4tov4\\\u003c/code\u003e registry key.\u003c/li\u003e\n\u003cli\u003eThe attacker configures a new port forwarding rule by creating a new subkey under \u003ccode\u003ev4tov4\\\u003c/code\u003e with specific settings for the local port, remote address, and remote port.\u003c/li\u003e\n\u003cli\u003eThe attacker sets the \u003ccode\u003eListenAddress\u003c/code\u003e, \u003ccode\u003eListenPort\u003c/code\u003e, \u003ccode\u003eConnectAddress\u003c/code\u003e, and \u003ccode\u003eConnectPort\u003c/code\u003e values within the new subkey.\u003c/li\u003e\n\u003cli\u003eThe attacker verifies the successful creation and activation of the port forwarding rule using \u003ccode\u003enetsh interface portproxy show v4tov4\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the newly created port forwarding rule to tunnel traffic through the compromised host, bypassing network segmentation.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the proxied connection to access internal resources and conduct further attacks, such as lateral movement or data exfiltration.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation enables attackers to bypass network segmentation restrictions, leading to unauthorized access to internal systems and data. This can facilitate lateral movement, data exfiltration, and further compromise of the network. The severity of the impact depends on the sensitivity of the accessible resources and the extent of the attacker\u0026rsquo;s lateral movement.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon registry event logging to capture modifications to the \u003ccode\u003eHKLM\\SYSTEM\\*ControlSet*\\Services\\PortProxy\\v4tov4\\\u003c/code\u003e registry subkeys, enabling detection of malicious port forwarding rule additions.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Port Forwarding Rule Addition via Registry Modification\u0026rdquo; to your SIEM to detect suspicious registry modifications related to port forwarding.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on identifying the process execution chain and the user account that performed the action.\u003c/li\u003e\n\u003cli\u003eRegularly review and audit existing port forwarding rules to identify and remove any unauthorized or suspicious configurations.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2026-05-port-forwarding-registry/","summary":"An adversary may abuse port forwarding to bypass network segmentation restrictions by creating a new port forwarding rule through modification of the Windows registry.","title":"Windows Port Forwarding Rule Addition via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2026-05-port-forwarding-registry/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","execution","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies suspicious child processes spawned by Zoom.exe, potentially indicating an attempt to evade detection or exploit vulnerabilities within the Zoom application. The rule focuses on detecting instances where command interpreters like cmd.exe, PowerShell, or PowerShell ISE are launched as child processes of Zoom. This behavior can be indicative of an attacker attempting to execute malicious commands or scripts within the context of the Zoom application, potentially escalating privileges or gaining unauthorized access to system resources. It\u0026rsquo;s crucial for defenders to investigate such occurrences, as they may signify ongoing exploitation or malicious activity leveraging Zoom as an initial access vector.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eUser launches the Zoom application (Zoom.exe).\u003c/li\u003e\n\u003cli\u003eA vulnerability in Zoom is exploited, or the user is socially engineered into running a malicious command.\u003c/li\u003e\n\u003cli\u003eZoom.exe spawns a child process, such as cmd.exe, powershell.exe, pwsh.exe, or powershell_ise.exe.\u003c/li\u003e\n\u003cli\u003eThe spawned process executes commands or scripts, potentially downloading or executing malware.\u003c/li\u003e\n\u003cli\u003eThe malicious script or command performs reconnaissance activities on the system.\u003c/li\u003e\n\u003cli\u003eThe script establishes persistence by creating a scheduled task or modifying registry keys.\u003c/li\u003e\n\u003cli\u003eThe attacker gains remote access to the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker performs lateral movement and data exfiltration.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation could allow attackers to execute arbitrary commands, escalate privileges, and compromise the affected system. Depending on the user\u0026rsquo;s privileges, attackers could gain access to sensitive data, install malware, or pivot to other systems on the network. The impact ranges from data breaches to complete system compromise, potentially affecting all users within the organization who utilize the Zoom application.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Suspicious Zoom Child Process\u0026rdquo; to your SIEM to detect command interpreters spawned by Zoom.exe. Tune the rule for your environment to minimize false positives.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture detailed information about process executions, which is essential for the Sigma rule above.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the command-line arguments and network connections of the spawned processes.\u003c/li\u003e\n\u003cli\u003eMonitor Windows Security Event Logs for process creation events related to Zoom.exe and its child processes to identify suspicious behavior.\u003c/li\u003e\n\u003cli\u003eConsider implementing application control policies to restrict the execution of unauthorized processes within the Zoom application context.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-11-suspicious-zoom-child-process/","summary":"A suspicious Zoom child process was detected, indicating a potential attempt to run unnoticed by masquerading as Zoom.exe or exploiting a vulnerability, resulting in the execution of cmd.exe, powershell.exe, pwsh.exe, or powershell_ise.exe.","title":"Suspicious Zoom Child Process Execution","url":"https://feed.craftedsignal.io/briefs/2024-11-suspicious-zoom-child-process/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","Sysmon","Crowdstrike","SentinelOne Cloud Funnel","Elastic Endgame"],"_cs_severities":["medium"],"_cs_tags":["powershell","malware","execution"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThis detection rule identifies the execution of PowerShell with suspicious argument values on Windows systems. This behavior is frequently associated with malware installation and other malicious activities. PowerShell is a powerful scripting language, and adversaries often exploit its capabilities to execute malicious scripts, download payloads, and obfuscate commands. The rule focuses on detecting patterns such as encoded commands, suspicious downloads (e.g., using WebClient or Invoke-WebRequest), and various obfuscation techniques used to evade detection. The rule is designed to work with various data sources, including Elastic Defend, Windows Security Event Logs, Sysmon, and third-party EDR solutions like CrowdStrike, Microsoft Defender XDR, and SentinelOne, enhancing its applicability across different environments.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system (e.g., through phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uses PowerShell to download a malicious payload from a remote server using commands like \u003ccode\u003eDownloadFile\u003c/code\u003e or \u003ccode\u003eDownloadString\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe downloaded payload is often encoded or obfuscated to evade detection. Common techniques include Base64 encoding, character manipulation, and compression.\u003c/li\u003e\n\u003cli\u003ePowerShell is then used to decode or deobfuscate the payload using methods like \u003ccode\u003e[Convert]::FromBase64String\u003c/code\u003e or \u003ccode\u003e[char[]](...) -join ''\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe deobfuscated payload is executed directly in memory using techniques like \u003ccode\u003eiex\u003c/code\u003e (Invoke-Expression) or \u003ccode\u003eReflection.Assembly.Load\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe executed payload performs malicious actions, such as installing malware, establishing persistence, or exfiltrating data.\u003c/li\u003e\n\u003cli\u003eThe attacker may use techniques like \u003ccode\u003eWebClient\u003c/code\u003e to download files from a remote URL.\u003c/li\u003e\n\u003cli\u003eCommands like \u003ccode\u003enslookup -q=txt\u003c/code\u003e are used for command and control.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to malware installation, data theft, system compromise, and further propagation of the attack within the network. The detection of suspicious PowerShell arguments helps to identify and prevent these malicious activities before significant damage can occur. Without proper detection, attackers can maintain persistence, escalate privileges, and compromise sensitive data. The rule helps defenders identify and respond to these threats quickly, minimizing the impact of potential attacks.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rules provided in this brief to your SIEM to detect suspicious PowerShell activity.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging with command line arguments to ensure the necessary data is captured for the Sigma rules to function effectively.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rules to determine the legitimacy of the PowerShell activity and take appropriate remediation steps.\u003c/li\u003e\n\u003cli\u003eContinuously tune the Sigma rules based on your environment to reduce false positives and improve detection accuracy.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-09-susp-powershell-args/","summary":"This rule identifies the execution of PowerShell with suspicious argument values, often observed during malware installation, by detecting unusual PowerShell arguments indicative of abuse, focusing on patterns like encoded commands, suspicious downloads, and obfuscation techniques.","title":"Suspicious Windows PowerShell Arguments Detected","url":"https://feed.craftedsignal.io/briefs/2024-09-susp-powershell-args/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike","SentinelOne Cloud Funnel","Sysmon","Windows Security Event Logs"],"_cs_severities":["medium"],"_cs_tags":["lolbas","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne","Elastic"],"content_html":"\u003cp\u003eThe Windows command line debugging utility, cdb.exe, is a legitimate tool used for debugging applications. However, adversaries can exploit it to execute unauthorized commands or shellcode, bypassing security measures. This can be achieved by running cdb.exe from non-standard installation paths and using specific command-line arguments to execute malicious commands. The LOLBAS project documents this technique, highlighting its potential for defense evasion. This activity has been observed across various environments, necessitating detection strategies that focus on identifying anomalous executions of cdb.exe.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system.\u003c/li\u003e\n\u003cli\u003eThe attacker copies cdb.exe to a non-standard location (outside \u0026ldquo;Program Files\u0026rdquo; and \u0026ldquo;Program Files (x86)\u0026rdquo;).\u003c/li\u003e\n\u003cli\u003eThe attacker executes cdb.exe with the \u003ccode\u003e-cf\u003c/code\u003e, \u003ccode\u003e-c\u003c/code\u003e, or \u003ccode\u003e-pd\u003c/code\u003e command-line arguments.\u003c/li\u003e\n\u003cli\u003eThese arguments are used to specify a command file or execute a direct command.\u003c/li\u003e\n\u003cli\u003eThe command file or command directly executes malicious code, such as shellcode.\u003c/li\u003e\n\u003cli\u003eThe malicious code performs actions such as creating new processes, modifying files, or establishing network connections.\u003c/li\u003e\n\u003cli\u003eThese actions allow the attacker to maintain persistence or escalate privileges.\u003c/li\u003e\n\u003cli\u003eThe ultimate goal is to evade defenses and execute arbitrary code on the system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows adversaries to execute arbitrary commands and shellcode on the affected system, potentially leading to complete system compromise. This can result in data theft, installation of malware, or further propagation within the network. The technique is effective at bypassing application whitelisting and other security controls that rely on standard execution paths.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Execution via Windows Command Debugging Utility\u0026rdquo; to your SIEM to detect suspicious cdb.exe executions (see rules section).\u003c/li\u003e\n\u003cli\u003eEnable process creation logging via Sysmon or Windows Security Event Logs to provide the necessary data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eImplement application whitelisting to prevent execution of cdb.exe from non-standard paths.\u003c/li\u003e\n\u003cli\u003eMonitor process command lines for the \u003ccode\u003e-cf\u003c/code\u003e, \u003ccode\u003e-c\u003c/code\u003e, and \u003ccode\u003e-pd\u003c/code\u003e flags when cdb.exe is executed.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of cdb.exe running from unusual directories to determine legitimacy.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-07-cdb-execution/","summary":"Adversaries can abuse the Windows command line debugging utility cdb.exe to execute commands or shellcode from non-standard paths, evading traditional security measures.","title":"Suspicious Execution via Windows Command Debugging Utility","url":"https://feed.craftedsignal.io/briefs/2024-07-cdb-execution/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows","registry-modification"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection rule identifies modifications to Subject Interface Package (SIP) providers, a critical component of the Windows cryptographic system responsible for validating file signatures. Attackers may attempt to subvert trust controls by modifying SIP providers, allowing them to bypass signature validation checks and potentially inject malicious code into trusted processes. This activity is a form of defense evasion, allowing unauthorized code execution. The rule focuses on detecting suspicious registry changes associated with SIP providers, while excluding known benign processes to minimize false positives. The rule is designed for data generated by Elastic Defend, but also supports third-party data sources like CrowdStrike, Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon. This activity is related to MITRE ATT\u0026amp;CK technique T1553.003 (SIP and Trust Provider Hijacking).\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system through various means (e.g., phishing, exploitation of vulnerabilities).\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to gain necessary permissions to modify the registry.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the registry keys associated with SIP providers, specifically targeting \u003ccode\u003eCryptSIPDllPutSignedDataMsg\u003c/code\u003e and \u003ccode\u003eTrust\\\\FinalPolicy\u003c/code\u003e locations.\u003c/li\u003e\n\u003cli\u003eThe attacker changes the \u003ccode\u003eDll\u003c/code\u003e value within these registry keys to point to a malicious DLL.\u003c/li\u003e\n\u003cli\u003eThe system, upon attempting to validate a file signature, loads the malicious DLL instead of the legitimate SIP provider.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL executes arbitrary code, potentially injecting it into other processes.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the injected code to further compromise the system or network.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data exfiltration, ransomware deployment, or establishing persistence.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of SIP providers allows attackers to bypass signature validation checks, leading to the execution of unsigned or malicious code. This can compromise the integrity of the system, leading to data breaches, system instability, or further propagation of malware within the network. The impact can range from individual workstation compromise to widespread organizational damage, depending on the scope of the attack.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect SIP Provider Modification via Registry\u003c/code\u003e to your SIEM and tune it for your environment to detect suspicious registry modifications related to SIP providers.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to collect the necessary data for the Sigma rules above.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the rules, focusing on the process responsible for the registry change and the DLL being loaded, as described in the rule\u0026rsquo;s triage section.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of unsigned or untrusted code.\u003c/li\u003e\n\u003cli\u003eMonitor the registry paths listed in the Sigma rules for unexpected changes.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-01-sip-provider-modification/","summary":"This rule detects modifications to the registered Subject Interface Package (SIP) providers, which are used by the Windows cryptographic system to validate file signatures, potentially indicating an attempt to bypass signature validation or inject code for defense evasion.","title":"SIP Provider Modification for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-sip-provider-modification/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","SentinelOne","Crowdstrike","Elastic"],"content_html":"\u003cp\u003eThis detection identifies the modification of Discretionary Access Control Lists (DACLs) for Windows services using the \u003ccode\u003esc.exe\u003c/code\u003e utility. Attackers can leverage this technique to deny access to a service, making it unmanageable or hiding it from system administrators and users. The detection rule focuses on identifying instances where \u003ccode\u003esc.exe\u003c/code\u003e is used with the \u003ccode\u003esdset\u003c/code\u003e argument, specifically targeting the denial of access for key user groups such as IU, SU, BA, SY, and WD. This activity is indicative of a defense evasion attempt aimed at hindering security tools or preventing remediation. The rule is designed for data generated by Elastic Defend, but also supports integrations with third-party data sources like CrowdStrike, Microsoft Defender XDR, and SentinelOne Cloud Funnel, offering broad coverage for detecting this malicious behavior across diverse environments.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system through various means (e.g., compromised credentials, phishing).\u003c/li\u003e\n\u003cli\u003eThe attacker elevates privileges to gain necessary permissions to modify service configurations.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003esc.exe\u003c/code\u003e with the \u003ccode\u003esdset\u003c/code\u003e command to modify the DACL of a targeted service.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003esdset\u003c/code\u003e command arguments specify the new security descriptor, denying access to specific user groups (e.g., IU, SU, BA, SY, WD).\u003c/li\u003e\n\u003cli\u003eThe service becomes inaccessible to the targeted user groups, potentially disrupting legitimate operations or security tools.\u003c/li\u003e\n\u003cli\u003eThe attacker may repeat this process for multiple services to further impair system functionality or evade detection.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the disabled or hidden services to maintain persistence or carry out other malicious activities.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of service DACLs can lead to a denial-of-service condition for legitimate users and system administrators. This can impair the functionality of critical security tools, hinder incident response efforts, and provide attackers with a persistent foothold on the compromised system. The hiding of services can also prevent users from identifying and removing malicious services. While the number of victims is not specified in the source, organizations across various sectors are potentially vulnerable to this type of attack.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eService DACL Modification via sc.exe\u003c/code\u003e to your SIEM to detect this specific behavior.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to provide the necessary data for the Sigma rule to function effectively.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances where \u003ccode\u003esc.exe\u003c/code\u003e is used with the \u003ccode\u003esdset\u003c/code\u003e argument and access denial flags, focusing on the targeted user groups (IU, SU, BA, SY, WD).\u003c/li\u003e\n\u003cli\u003eImplement strict access controls and monitor for unauthorized attempts to modify service configurations.\u003c/li\u003e\n\u003cli\u003eRegularly audit service permissions to identify and remediate any unauthorized changes.\u003c/li\u003e\n\u003cli\u003eReview and update endpoint protection policies to prevent similar threats in the future, ensuring that all systems are equipped with the latest security patches and configurations.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-07-service-dacl-modification/","summary":"Detection of service DACL modifications via `sc.exe` using the `sdset` command, potentially leading to defense evasion by denying service access to legitimate users or system accounts.","title":"Service DACL Modification via sc.exe","url":"https://feed.craftedsignal.io/briefs/2024-07-service-dacl-modification/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel","CrowdStrike"],"_cs_severities":["low"],"_cs_tags":["defense evasion","impact","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThe Sysinternals SDelete utility is a legitimate tool developed by Microsoft for securely deleting files by overwriting and renaming them multiple times. While intended for secure data disposal, adversaries can abuse SDelete to remove forensic artifacts, destroy evidence of their activities, and impede data recovery efforts after a successful ransomware attack or data theft. This activity can be used as a post-exploitation technique. This detection rule focuses on identifying file name patterns indicative of SDelete\u0026rsquo;s operation, specifically detecting files with names resembling \u0026ldquo;*AAA.AAA\u0026rdquo;. The rule is designed to work with various endpoint detection and response solutions, including Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, and CrowdStrike.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to gain the necessary permissions to delete files.\u003c/li\u003e\n\u003cli\u003eThe attacker deploys or utilizes an existing copy of the SDelete utility.\u003c/li\u003e\n\u003cli\u003eThe attacker executes SDelete against targeted files or directories.\u003c/li\u003e\n\u003cli\u003eSDelete overwrites the targeted file(s) multiple times with random data.\u003c/li\u003e\n\u003cli\u003eSDelete renames the file(s) multiple times, often with patterns such as \u0026ldquo;*AAA.AAA\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eSDelete deletes the file(s) making recovery difficult.\u003c/li\u003e\n\u003cli\u003eThe attacker removes SDelete or any associated tools to further cover their tracks.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of this technique can result in the permanent deletion of crucial forensic artifacts, log files, or even critical data. This can severely hinder incident response efforts, making it challenging to identify the scope of the attack, the attacker\u0026rsquo;s methods, and the compromised assets. The number of victims and affected sectors depends on the scale of the initial breach and the attacker\u0026rsquo;s objectives.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Potential Secure File Deletion via SDelete Utility\u0026rdquo; detection rule to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the detection rule, focusing on the process execution chain and identifying the user account involved.\u003c/li\u003e\n\u003cli\u003eReview the privileges assigned to the user account to ensure the least privilege principle is followed.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) logging to enhance visibility into file creation events.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-01-28-sdelete-filename-rename/","summary":"This rule detects file name patterns generated by the use of Sysinternals SDelete utility, potentially used by attackers to delete forensic indicators and hinder data recovery efforts.","title":"Potential Secure File Deletion via SDelete Utility","url":"https://feed.craftedsignal.io/briefs/2024-01-28-sdelete-filename-rename/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","Elastic Endgame"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","ntlm","registry-modification","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThis rule detects a specific defense evasion technique where an attacker modifies the Windows registry to force a system to use the less secure NTLMv1 authentication protocol. This is known as a NetNTLMv1 downgrade attack. The registry modification involves changing the \u003ccode\u003eLmCompatibilityLevel\u003c/code\u003e value, which controls the authentication level. Attackers with local administrator privileges can perform this modification to weaken the authentication mechanism, making it easier to intercept and crack credentials. The rule is designed to detect this activity by monitoring registry events from various sources, including Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, Sysmon, and Crowdstrike. It is important to monitor for this activity as it can lead to credential theft and further compromise of the system.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains local administrator privileges on a Windows system.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a registry editor or command-line tool (e.g., \u003ccode\u003ereg.exe\u003c/code\u003e, PowerShell) to modify the \u003ccode\u003eLmCompatibilityLevel\u003c/code\u003e value in the registry.\u003c/li\u003e\n\u003cli\u003eThe attacker navigates to one of the following registry paths: \u003ccode\u003eHKLM\\System\\CurrentControlSet\\Control\\Lsa\\LmCompatibilityLevel\u003c/code\u003e or \u003ccode\u003eHKLM\\SYSTEM\\CurrentControlSet\\Control\\Lsa\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker sets the \u003ccode\u003eLmCompatibilityLevel\u003c/code\u003e value to \u0026ldquo;0\u0026rdquo;, \u0026ldquo;1\u0026rdquo;, or \u0026ldquo;2\u0026rdquo; (or their hexadecimal equivalents \u0026ldquo;0x00000000\u0026rdquo;, \u0026ldquo;0x00000001\u0026rdquo;, \u0026ldquo;0x00000002\u0026rdquo;). These values force the system to use NTLMv1.\u003c/li\u003e\n\u003cli\u003eThe system now uses NTLMv1 for authentication attempts.\u003c/li\u003e\n\u003cli\u003eThe attacker initiates a man-in-the-middle attack to capture NTLMv1 authentication traffic using tools like Responder or Inveigh.\u003c/li\u003e\n\u003cli\u003eThe captured NTLMv1 hashes are cracked using brute-force or dictionary attacks, revealing the user\u0026rsquo;s credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the compromised credentials to gain unauthorized access to network resources or other systems.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful NetNTLMv1 downgrade attack can lead to the compromise of user credentials, enabling attackers to move laterally within the network, access sensitive data, and potentially escalate privileges. The impact can range from data breaches to complete system compromise, depending on the attacker\u0026rsquo;s objectives and the compromised user\u0026rsquo;s privileges.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Potential NetNTLMv1 Downgrade Attack\u0026rdquo; to detect registry modifications setting \u003ccode\u003eLmCompatibilityLevel\u003c/code\u003e to insecure values (0, 1, 2) within the specified registry paths.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to ensure the necessary data is available for the Sigma rule to function correctly.\u003c/li\u003e\n\u003cli\u003eReview registry event logs for unauthorized modifications of \u003ccode\u003eLmCompatibilityLevel\u003c/code\u003e to confirm legitimate administrative actions.\u003c/li\u003e\n\u003cli\u003eImplement strict access control policies to limit local administrator privileges and reduce the attack surface.\u003c/li\u003e\n\u003cli\u003eMonitor the references URL for updates on recommended security configurations related to NTLM authentication.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2026-05-netntlmv1-downgrade/","summary":"This brief details a registry modification attack that downgrades the system to NTLMv1 authentication, enabling NetNTLMv1 downgrade attacks, typically performed with local administrator privileges on Windows systems.","title":"Potential NetNTLMv1 Downgrade Attack via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2026-05-netntlmv1-downgrade/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["WinWord.exe","EXPLORER.EXE","w3wp.exe","DISM.EXE","Microsoft Defender XDR"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","execution","dll-side-loading","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eThis detection rule identifies instances of Windows trusted programs such as WinWord.exe, EXPLORER.EXE, w3wp.exe, and DISM.EXE executing from unusual paths or after being renamed, which may indicate DLL side-loading. DLL side-loading is a defense evasion technique where a malicious DLL is placed in the same directory as a legitimate executable. When the executable runs, it may load the malicious DLL instead of the legitimate one, allowing the attacker to execute arbitrary code within the context of the trusted process. The detection logic focuses on process executions that deviate from standard installation paths. The targeted processes are commonly used and often whitelisted, making this a potent technique for adversaries to bypass security controls.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system (e.g., through phishing or exploitation of a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker identifies a trusted Windows program vulnerable to DLL side-loading (WinWord.exe, EXPLORER.EXE, w3wp.exe, or DISM.EXE).\u003c/li\u003e\n\u003cli\u003eThe attacker drops a malicious DLL into a directory where the trusted program is expected to load DLLs from, often alongside a renamed or copied version of the legitimate executable.\u003c/li\u003e\n\u003cli\u003eAlternatively, the attacker renames the trusted program and places it in a non-standard path.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the renamed or moved trusted program from the non-standard path.\u003c/li\u003e\n\u003cli\u003eThe trusted program loads the malicious DLL due to DLL search order hijacking.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL executes arbitrary code within the context of the trusted process.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves persistence, elevates privileges, or performs other malicious activities, potentially evading detection due to the trusted process context.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful DLL side-loading attack allows the attacker to execute arbitrary code within the context of a trusted Microsoft process. This can lead to privilege escalation, persistence, and further compromise of the system. Since the malicious code is running within a trusted process, it can bypass application whitelisting and other security controls, making it difficult to detect. This can lead to data theft, system disruption, or the installation of malware.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Potential DLL Side-Loading via Trusted Microsoft Programs\u0026rdquo; to your SIEM to detect suspicious executions of trusted programs from non-standard paths or with modifications.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to provide the necessary data for the Sigma rule to function correctly.\u003c/li\u003e\n\u003cli\u003eReview and tune the exclusion paths in the Sigma rule to avoid false positives from legitimate software updates, custom enterprise applications, or virtual environments.\u003c/li\u003e\n\u003cli\u003eMonitor process execution paths using the Sigma rule \u0026ldquo;Potential DLL Side-Loading via Trusted Microsoft Programs\u0026rdquo; and investigate any deviations from standard installation paths.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2026-05-dll-side-loading/","summary":"This rule detects potential DLL side-loading attempts by identifying instances of Windows trusted programs (WinWord.exe, EXPLORER.EXE, w3wp.exe, DISM.EXE) being started after being renamed or from a non-standard path, which is a common technique to evade defenses by side-loading a malicious DLL into the memory space of a trusted process.","title":"Potential DLL Side-Loading via Trusted Microsoft Programs","url":"https://feed.craftedsignal.io/briefs/2026-05-dll-side-loading/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Crowdstrike FDR"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","lateral-movement","persistence","registry-modification"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThe LocalAccountTokenFilterPolicy is a Windows registry setting that, when enabled (set to 1), allows remote connections from local members of the Administrators group to be granted full high-integrity tokens during negotiation. This bypasses User Account Control (UAC) restrictions, allowing for elevated privileges remotely. Attackers may modify this registry setting to facilitate lateral movement within a network. This rule detects modifications to this specific registry setting, alerting on potential unauthorized changes that could lead to defense evasion and privilege escalation. The modification of this policy has been observed being leveraged in conjunction with pass-the-hash attacks.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to a system through an exploit, such as phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker obtains local administrator credentials on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the LocalAccountTokenFilterPolicy registry key to a value of 1. This is done to allow remote connections from local administrator accounts to receive high-integrity tokens. The registry key is typically located at \u003ccode\u003eHKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\LocalAccountTokenFilterPolicy\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages a \u0026ldquo;pass the hash\u0026rdquo; attack (T1550.002) using the compromised local administrator credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to move laterally to other systems within the network using the \u0026ldquo;pass the hash\u0026rdquo; technique and the modified LocalAccountTokenFilterPolicy.\u003c/li\u003e\n\u003cli\u003eDue to the LocalAccountTokenFilterPolicy being enabled, the remote connection from the local administrator account receives a full high-integrity token.\u003c/li\u003e\n\u003cli\u003eThe attacker bypasses UAC on the remote system, gaining elevated privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker performs malicious activities on the remote system, such as data exfiltration or deploying ransomware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of the LocalAccountTokenFilterPolicy allows attackers to bypass User Account Control (UAC) and gain elevated privileges on remote systems, potentially leading to unauthorized access to sensitive data, lateral movement across the network, and the deployment of ransomware. The overall impact can include data breaches, financial loss, and reputational damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eLocal Account TokenFilter Policy Enabled\u003c/code\u003e to your SIEM and tune for your environment to detect unauthorized modifications to the LocalAccountTokenFilterPolicy registry key.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to capture modifications to the registry, which is required for the \u003ccode\u003eLocal Account TokenFilter Policy Enabled\u003c/code\u003e Sigma rule.\u003c/li\u003e\n\u003cli\u003eReview the processes excluded in the rule query and ensure they are legitimate and necessary to prevent false positives.\u003c/li\u003e\n\u003cli\u003eMonitor registry events for changes to the \u003ccode\u003eHKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\LocalAccountTokenFilterPolicy\u003c/code\u003e path, specifically looking for changes to the value data.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-01-02-local-account-token-filter-policy-disabled/","summary":"Adversaries may modify the LocalAccountTokenFilterPolicy registry key to bypass User Account Control (UAC) and gain elevated privileges remotely by granting high-integrity tokens to remote connections from local administrators, facilitating lateral movement and defense evasion.","title":"Local Account TokenFilter Policy Modification for Defense Evasion and Lateral Movement","url":"https://feed.craftedsignal.io/briefs/2024-01-02-local-account-token-filter-policy-disabled/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR"],"_cs_severities":["low"],"_cs_tags":["discovery","domain-trust","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThe \u003ccode\u003edsquery.exe\u003c/code\u003e utility is a command-line tool in Windows used to query Active Directory. Attackers may leverage \u003ccode\u003edsquery.exe\u003c/code\u003e to discover domain trust relationships within a Windows environment, mapping out potential lateral movement paths. This discovery is often an early stage in reconnaissance, before an attacker attempts to move laterally to other systems. This activity can be detected across various endpoint detection platforms including Elastic Defend, CrowdStrike, Microsoft Defender XDR, and SentinelOne. This activity is not inherently malicious, as administrators also use it for legitimate purposes.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a compromised host within the target environment.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003edsquery.exe\u003c/code\u003e with the argument \u003ccode\u003eobjectClass=trustedDomain\u003c/code\u003e to enumerate domain trusts.\u003c/li\u003e\n\u003cli\u003eThe command execution is logged by endpoint detection and response (EDR) solutions or Windows Security Event Logs.\u003c/li\u003e\n\u003cli\u003eThe attacker parses the output of the \u003ccode\u003edsquery.exe\u003c/code\u003e command to identify trusted domains and their attributes.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the discovered trust information to plan lateral movement strategies.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to authenticate to other systems within the trusted domains using stolen credentials or other exploits.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful enumeration of domain trusts enables attackers to map out the Active Directory environment and identify potential pathways for lateral movement. While the enumeration itself is low impact, it facilitates subsequent actions like credential theft, privilege escalation, and data exfiltration. This can lead to widespread compromise across the organization, impacting numerous systems and sensitive data.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Enumerating Domain Trusts via DSQUERY.EXE\u0026rdquo; to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any execution of \u003ccode\u003edsquery.exe\u003c/code\u003e with the argument \u003ccode\u003eobjectClass=trustedDomain\u003c/code\u003e to identify potentially malicious activity.\u003c/li\u003e\n\u003cli\u003eMonitor process execution events for \u003ccode\u003edsquery.exe\u003c/code\u003e to detect suspicious command-line arguments and execution patterns.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2026-05-domain-trust-discovery/","summary":"Adversaries may use the `dsquery.exe` command-line utility to enumerate trust relationships for lateral movement in Windows multi-domain environments.","title":"Enumerating Domain Trusts via DSQUERY.EXE","url":"https://feed.craftedsignal.io/briefs/2026-05-domain-trust-discovery/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","Sysmon","Visual Studio Code"],"_cs_severities":["medium"],"_cs_tags":["command-and-control","vscode","remote-access-tools","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","GitHub","Elastic"],"content_html":"\u003cp\u003eThis detection focuses on identifying the misuse of Visual Studio Code\u0026rsquo;s (VScode) remote tunnel feature to establish unauthorized access or control over systems. While the VScode remote tunnel feature is designed to allow developers to connect to remote environments seamlessly, attackers can abuse this functionality for malicious purposes. The rule specifically looks for the execution of the VScode portable binary with the \u0026ldquo;tunnel\u0026rdquo; command-line option, which is indicative of an attempt to establish a remote tunnel session to either GitHub or a remote VScode instance. Successful exploitation can lead to command and control capabilities, allowing attackers to remotely manage and compromise the affected system. The rule aims to detect this suspicious behavior by monitoring process execution and command-line arguments.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the target system through unspecified means.\u003c/li\u003e\n\u003cli\u003eThe attacker downloads a portable version of Visual Studio Code (VScode) onto the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the VScode binary with the \u003ccode\u003etunnel\u003c/code\u003e command-line argument to initiate a remote tunnel session.\u003c/li\u003e\n\u003cli\u003eThe attacker specifies additional arguments such as \u003ccode\u003e--accept-server-license-terms\u003c/code\u003e to bypass license agreement prompts.\u003c/li\u003e\n\u003cli\u003eThe VScode tunnel attempts to establish a connection to a remote server, potentially a GitHub repository or a remote VScode instance controlled by the attacker.\u003c/li\u003e\n\u003cli\u003eIf successful, the tunnel creates a persistent connection, allowing the attacker to execute commands and transfer files.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the established tunnel to remotely access the compromised system, enabling them to perform malicious activities such as data exfiltration or lateral movement.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistent access through the established tunnel, allowing for long-term command and control of the compromised system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to establish a persistent command and control channel, enabling them to remotely manage the compromised system. This can lead to data theft, deployment of ransomware, or further lateral movement within the network. While the number of potential victims and specific sectors targeted are not explicitly stated, the widespread use of VScode makes a wide range of organizations vulnerable.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Attempt to Establish VScode Remote Tunnel\u0026rdquo; rule to detect suspicious VScode tunnel activity in your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process-creation logging to capture the necessary process execution data.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the rule, focusing on the command-line arguments and process behaviors to confirm malicious intent.\u003c/li\u003e\n\u003cli\u003eMonitor network connections originating from VScode processes for unusual or unauthorized connections to external servers.\u003c/li\u003e\n\u003cli\u003eReview and whitelist legitimate uses of VScode\u0026rsquo;s tunnel feature by authorized developers to reduce false positives.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-09-vscode-tunnel/","summary":"The rule detects the execution of the VScode portable binary with the tunnel command line option, potentially indicating an attempt to establish a remote tunnel session to Github or a remote VScode instance for unauthorized access and command and control.","title":"Detection of VScode Remote Tunneling for Command and Control","url":"https://feed.craftedsignal.io/briefs/2024-09-vscode-tunnel/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Defend","Windows Defender Application Control","Crowdstrike FDR","Sysmon"],"_cs_severities":["high"],"_cs_tags":["wdac","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers are increasingly targeting Windows Defender Application Control (WDAC) to disable or weaken endpoint defenses. By crafting malicious WDAC policies, adversaries can block legitimate security software and evade detection. This technique involves creating WDAC policy files (.p7b or .cip) in protected system directories using unauthorized processes. The activity often occurs when attackers have already gained a foothold in the system and are attempting to solidify their position. Successful deployment of a malicious WDAC policy can significantly hinder incident response and allow malware to operate undetected. This tactic has gained traction since late 2024, with offensive tools like Krueger demonstrating the potential for weaponizing WDAC against EDR solutions.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003e\u003cstrong\u003eInitial Access:\u003c/strong\u003e The attacker gains initial access to the system through methods such as phishing or exploiting a software vulnerability.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003ePrivilege Escalation:\u003c/strong\u003e The attacker escalates privileges to gain administrative access, which is required to modify WDAC policies.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003ePolicy Creation:\u003c/strong\u003e The attacker crafts a malicious WDAC policy using tools or scripts. This policy is designed to block specific security products or processes.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eStaging:\u003c/strong\u003e The malicious policy is staged in a temporary location on the system, often within user-writable directories.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003ePolicy Placement:\u003c/strong\u003e The attacker moves the malicious WDAC policy file (.p7b or .cip) to a protected system directory, such as \u003ccode\u003eC:\\Windows\\System32\\CodeIntegrity\\\u003c/code\u003e or \u003ccode\u003eC:\\Windows\\System32\\CodeIntegrity\\CiPolicies\\Active\\\u003c/code\u003e. The tool used may be a Living-off-the-Land Binary (LOLBin) or a custom .NET assembly.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eActivation:\u003c/strong\u003e The attacker triggers the activation of the new WDAC policy, which often requires a system reboot or the use of a service control utility.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eDefense Evasion:\u003c/strong\u003e Once the policy is active, the targeted security products are blocked, allowing the attacker to operate with reduced risk of detection.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eLateral Movement/Objectives:\u003c/strong\u003e With defenses weakened, the attacker can move laterally within the network, exfiltrate data, or achieve other objectives.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack targeting WDAC can severely impair an organization\u0026rsquo;s ability to detect and respond to threats. By blocking security software, attackers can operate with impunity, leading to data breaches, financial losses, and reputational damage. Observed damage includes disabled endpoint detection and response (EDR) solutions, allowing ransomware and other malware to execute without interference. The scope of impact can range from individual workstations to entire domains, depending on the breadth of the WDAC policy deployment.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;WDAC Policy File by an Unusual Process\u0026rdquo; Sigma rule to your SIEM to detect unauthorized WDAC policy modifications.\u003c/li\u003e\n\u003cli\u003eMonitor file creation events with extensions .p7b and .cip in \u003ccode\u003eC:\\Windows\\System32\\CodeIntegrity\\\u003c/code\u003e and \u003ccode\u003eC:\\Windows\\System32\\CodeIntegrity\\CiPolicies\\Active\\\u003c/code\u003e directories, specifically filtering for processes other than \u003ccode\u003epoqexec.exe\u003c/code\u003e, \u003ccode\u003eTiWorker.exe\u003c/code\u003e, and \u003ccode\u003eomadmclient.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) logging to capture file creation events and provide the necessary data for the Sigma rule to function effectively.\u003c/li\u003e\n\u003cli\u003eImplement strict access control policies on WDAC policy directories to prevent unauthorized modification.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-11-02T12:00:00Z","date_published":"2024-11-02T12:00:00Z","id":"/briefs/2024-11-wdac-policy-evasion/","summary":"Adversaries may use a specially crafted Windows Defender Application Control (WDAC) policy to restrict the execution of security products, detected by unusual process creation of WDAC policy files.","title":"WDAC Policy File Creation by Unusual Process","url":"https://feed.craftedsignal.io/briefs/2024-11-wdac-policy-evasion/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","hide-artifacts","alternate-data-stream"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection rule identifies the creation or execution of Alternate Data Streams (ADS) within the root directory of a volume on Windows systems. Attackers leverage this technique to conceal malicious tools or data, as ADSs created in this manner are not easily discoverable by standard system utilities. This method allows for the persistence and execution of malware while evading typical detection mechanisms. This rule is designed for data generated by Elastic Defend, Microsoft Defender XDR, and SentinelOne Cloud Funnel, providing broad coverage across different endpoint security solutions. Monitoring for ADS activity at the volume root is crucial to identify potential defense evasion attempts and hidden malicious payloads.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker gains initial access to the target system (e.g., through phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes a script or program (e.g., PowerShell) to create a hidden ADS at the root of a volume (e.g., \u003ccode\u003eC:\\:evil.exe\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe ADS is populated with malicious code, such as a reverse shell or malware payload.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a command-line tool or script to execute the hidden ADS file. For example: \u003ccode\u003ewmic process call create \u0026quot;cmd.exe /c start C:\\:evil.exe\u0026quot;\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe malicious code within the ADS executes, allowing the attacker to perform unauthorized actions, such as data exfiltration or establishing persistence.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the hidden ADS to maintain persistence on the system, ensuring continued access even after reboots.\u003c/li\u003e\n\u003cli\u003eThe attacker further leverages the compromised system to move laterally within the network, compromising additional systems and escalating privileges.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to hide malicious tools and maintain persistence on compromised systems. The creation of ADSs at the volume root directory makes it difficult for administrators and security tools to detect the presence of malware. This can lead to prolonged compromise, data breaches, and significant disruption of business operations. The rule has a risk score of 47, and a medium severity is applied.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rules provided in this brief to your SIEM to detect ADS creation and execution at the volume root directory.\u003c/li\u003e\n\u003cli\u003eEnable logging for file creation events (Sysmon Event ID 11) and process creation events (Sysmon Event ID 1) for enhanced visibility into ADS activity.\u003c/li\u003e\n\u003cli\u003eInvestigate alerts generated by the Sigma rules to determine the legitimacy of ADS creation or execution, focusing on processes and file paths that match the \u003ccode\u003e[A-Z]:\\\\:.+\u003c/code\u003e regex pattern in the rule query.\u003c/li\u003e\n\u003cli\u003eRegularly scan systems for hidden ADS files using specialized tools to uncover any potential malicious files.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of unauthorized applications and prevent the creation of malicious ADSs.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-07-08T12:00:00Z","date_published":"2024-07-08T12:00:00Z","id":"/briefs/2024-07-root-dir-ads-creation/","summary":"Detection of Alternate Data Stream (ADS) creation at a volume root directory, a technique used to hide malware and tools by exploiting how ADSs in root directories are not readily visible to standard system utilities, indicating a defense evasion attempt.","title":"Alternate Data Stream Creation/Execution at Volume Root Directory","url":"https://feed.craftedsignal.io/briefs/2024-07-root-dir-ads-creation/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Veeam Backup"],"_cs_severities":["medium"],"_cs_tags":["veeam","credential-access","mssql","windows","ransomware"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Veeam"],"content_html":"\u003cp\u003eAttackers are increasingly targeting backup infrastructure to maximize the impact of ransomware and data exfiltration attacks. Veeam, a popular backup and disaster recovery solution, stores credentials for backup operations in MSSQL databases. An attacker who gains access to these databases may attempt to use tools like \u003ccode\u003esqlcmd.exe\u003c/code\u003e or PowerShell commands (e.g., \u003ccode\u003eInvoke-Sqlcmd\u003c/code\u003e) to extract and decrypt these credentials. This tactic allows the attacker to compromise the backups themselves, preventing recovery and increasing pressure on the victim. This activity has been observed in real-world incidents, such as those involving the Diavol ransomware. Defenders should monitor for suspicious command-line activity targeting Veeam credentials within MSSQL environments.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial access to the target environment is gained through methods such as phishing or exploiting a vulnerability in a public-facing application.\u003c/li\u003e\n\u003cli\u003eThe attacker performs reconnaissance to identify the location of the Veeam MSSQL database server.\u003c/li\u003e\n\u003cli\u003eThe attacker obtains valid credentials or exploits a vulnerability to gain access to the Veeam MSSQL database server.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003esqlcmd.exe\u003c/code\u003e or uses PowerShell commands (e.g., \u003ccode\u003eInvoke-Sqlcmd\u003c/code\u003e) to query the \u003ccode\u003e[VeeamBackup].[dbo].[Credentials]\u003c/code\u003e table.\u003c/li\u003e\n\u003cli\u003eThe attacker retrieves the encrypted Veeam credentials from the database.\u003c/li\u003e\n\u003cli\u003eThe attacker decrypts the Veeam credentials using custom scripts or tools, potentially leveraging the Veeam backup server itself.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the compromised Veeam credentials to access and delete or encrypt backup data.\u003c/li\u003e\n\u003cli\u003eThe attacker deploys ransomware on the remaining systems, knowing that recovery from backups is now impossible.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful compromise of Veeam credentials can have devastating consequences. Attackers can encrypt or delete backup data, making recovery impossible and significantly increasing the impact of ransomware attacks. This can lead to prolonged downtime, data loss, financial losses, and reputational damage. Organizations relying on Veeam for backup and recovery should prioritize monitoring and securing their Veeam infrastructure to prevent credential access and backup compromise.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture command-line activity, specifically \u003ccode\u003esqlcmd.exe\u003c/code\u003e and PowerShell.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Potential Veeam Credential Access Command\u0026rdquo; to detect suspicious command executions targeting Veeam credentials in MSSQL databases.\u003c/li\u003e\n\u003cli\u003eReview and restrict access controls to the Veeam MSSQL database, ensuring only authorized personnel and services have access.\u003c/li\u003e\n\u003cli\u003eMonitor for unusual login activity and failed login attempts to the Veeam MSSQL database server.\u003c/li\u003e\n\u003cli\u003eImplement multi-factor authentication for all accounts with access to Veeam infrastructure.\u003c/li\u003e\n\u003cli\u003eRegularly audit Veeam backup configurations and logs to identify any unauthorized modifications or access attempts.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-07-03T12:00:00Z","date_published":"2024-07-03T12:00:00Z","id":"/briefs/2024-07-veeam-credential-access/","summary":"Attackers can leverage sqlcmd.exe or PowerShell commands like Invoke-Sqlcmd to access Veeam credentials stored in MSSQL databases, potentially targeting backups for destructive operations such as ransomware attacks.","title":"Potential Veeam Credential Access via SQL Commands","url":"https://feed.craftedsignal.io/briefs/2024-07-veeam-credential-access/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike FDR","SentinelOne Cloud Funnel","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["credential-access","windows","wbadmin","ntds.dit"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies the execution of \u003ccode\u003ewbadmin.exe\u003c/code\u003e with arguments indicative of an attempt to access and dump the NTDS.dit file from a Windows domain controller. Attackers with sufficient privileges, specifically those belonging to groups like Backup Operators, can abuse the legitimate \u003ccode\u003ewbadmin.exe\u003c/code\u003e utility to create a backup of the Active Directory database (NTDS.dit). This file contains sensitive credential information, and once obtained, attackers can extract password hashes and compromise the entire domain. This activity is often part of a larger attack aimed at gaining persistent access and control over the network. The Elastic detection rule was published on 2024-06-05 and last updated on 2026-05-04.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system within the target network. This may be achieved through phishing, exploiting vulnerabilities, or compromised credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to obtain membership in the Backup Operators group or a similar privileged group capable of running backups.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003ewbadmin.exe\u003c/code\u003e with the \u003ccode\u003erecovery\u003c/code\u003e argument, targeting the NTDS.dit file. The command line includes parameters to create a system state backup.\u003c/li\u003e\n\u003cli\u003eWbadmin creates a backup of the system state, including the NTDS.dit file, in a specified location.\u003c/li\u003e\n\u003cli\u003eThe attacker copies the NTDS.dit file from the backup location to a separate location for offline analysis.\u003c/li\u003e\n\u003cli\u003eThe attacker uses tools such as \u003ccode\u003entdsutil.exe\u003c/code\u003e or \u003ccode\u003esecretsdump.py\u003c/code\u003e to extract password hashes from the NTDS.dit file.\u003c/li\u003e\n\u003cli\u003eThe attacker cracks the password hashes or uses them in pass-the-hash attacks to gain access to other systems and resources within the domain.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves domain dominance and persistence, allowing them to control critical systems and data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to dump credentials from the NTDS.dit file, leading to complete compromise of the Active Directory domain. This enables them to move laterally, access sensitive data, and establish persistent control over the environment. The impact can include data breaches, ransomware deployment, and long-term disruption of business operations. The medium risk score indicates that while the attack requires specific privileges, the consequences are significant if successful.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable process creation logging with command line arguments to detect \u003ccode\u003ewbadmin.exe\u003c/code\u003e execution as described in the Attack Chain (Data Source: Windows Security Event Logs, Sysmon).\u003c/li\u003e\n\u003cli\u003eImplement the provided Sigma rule to detect suspicious \u003ccode\u003ewbadmin.exe\u003c/code\u003e execution with NTDS.dit related arguments in your SIEM (Rule: NTDS Dump via Wbadmin).\u003c/li\u003e\n\u003cli\u003eMonitor and restrict membership in privileged groups like Backup Operators to minimize the risk of abuse (Reference: \u003ca href=\"https://medium.com/r3d-buck3t/windows-privesc-with-sebackupprivilege-65d2cd1eb960)\"\u003ehttps://medium.com/r3d-buck3t/windows-privesc-with-sebackupprivilege-65d2cd1eb960)\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eReview and whitelist legitimate backup schedules or disaster recovery processes to reduce false positives (False positive analysis).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-07-03T10:00:00Z","date_published":"2024-07-03T10:00:00Z","id":"/briefs/2024-07-ntds-dump-wbadmin/","summary":"Attackers with Backup Operator privileges may abuse wbadmin.exe to access the NTDS.dit file, enabling credential dumping and domain compromise.","title":"NTDS Dump via Wbadmin","url":"https://feed.craftedsignal.io/briefs/2024-07-ntds-dump-wbadmin/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Management Console File","Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["execution","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers may exploit Microsoft Management Console (MMC) by executing .msc files from non-standard directories to bypass security controls. This technique can be used for initial access and execution. This detection focuses on identifying the execution of \u003ccode\u003emmc.exe\u003c/code\u003e with \u003ccode\u003e.msc\u003c/code\u003e files from paths outside the typical system directories, which are generally considered trusted. By monitoring process executions and filtering out known legitimate paths, analysts can identify potentially malicious activity related to the misuse of MMC. The rule aims to detect deviations from standard administrative practices that could indicate unauthorized access or command execution via malicious or compromised \u003ccode\u003e.msc\u003c/code\u003e files. The detection logic specifically excludes executions from common directories like \u003ccode\u003eSystem32\u003c/code\u003e, \u003ccode\u003eSysWOW64\u003c/code\u003e, and \u003ccode\u003eProgram Files\u003c/code\u003e.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system through an unspecified method.\u003c/li\u003e\n\u003cli\u003eThe attacker places a malicious \u003ccode\u003e.msc\u003c/code\u003e file in an unusual or untrusted directory (e.g., \u003ccode\u003eC:\\Users\\Public\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003emmc.exe\u003c/code\u003e with the malicious \u003ccode\u003e.msc\u003c/code\u003e file as an argument from the untrusted path.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003emmc.exe\u003c/code\u003e processes the \u003ccode\u003e.msc\u003c/code\u003e file, potentially executing embedded commands or scripts.\u003c/li\u003e\n\u003cli\u003eThe malicious \u003ccode\u003e.msc\u003c/code\u003e file performs unauthorized actions on the system, such as modifying system settings or executing arbitrary code.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the execution context of \u003ccode\u003emmc.exe\u003c/code\u003e to bypass security controls and escalate privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker may establish persistence by creating a scheduled task or modifying registry keys to execute the malicious \u003ccode\u003e.msc\u003c/code\u003e file automatically.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to unauthorized access, command execution, and privilege escalation, potentially compromising the entire system. While specific victim counts or sector targeting are not available, the technique is applicable across various Windows environments. The use of a trusted system binary like \u003ccode\u003emmc.exe\u003c/code\u003e for malicious purposes can evade traditional security measures, making detection more challenging.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eImplement the Sigma rule \u003ccode\u003eMicrosoft Management Console File from Unusual Path\u003c/code\u003e to detect the execution of \u003ccode\u003emmc.exe\u003c/code\u003e with \u003ccode\u003e.msc\u003c/code\u003e files from untrusted paths.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging with command-line arguments to provide the necessary data for the Sigma rule to function effectively.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the origin and content of the \u003ccode\u003e.msc\u003c/code\u003e file.\u003c/li\u003e\n\u003cli\u003eConsider implementing application control policies to restrict the execution of \u003ccode\u003e.msc\u003c/code\u003e files to authorized directories only.\u003c/li\u003e\n\u003cli\u003eReview and audit the use of MMC in the environment to identify any legitimate use cases that might trigger false positives.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-07-03T10:00:00Z","date_published":"2024-07-03T10:00:00Z","id":"/briefs/2024-07-mmc-untrusted-path/","summary":"Adversaries may use Microsoft Management Console (MMC) files from untrusted paths to bypass security controls for initial access and execution on Windows systems.","title":"Microsoft Management Console File Execution from Unusual Path","url":"https://feed.craftedsignal.io/briefs/2024-07-mmc-untrusted-path/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Endgame","Crowdstrike"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","registry-modification","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThe DNS Global Query Block List (GQBL) is a Windows security feature designed to prevent the resolution of specific DNS names, commonly exploited in attacks like WPAD spoofing. Attackers who have obtained elevated privileges, such as DNSAdmin, can modify or disable this list to bypass security controls. This allows exploitation of hosts running WPAD with default settings. The modification of the GQBL can be used for privilege escalation and lateral movement within a network. This rule detects changes to the registry values associated with the GQBL, specifically \u0026ldquo;EnableGlobalQueryBlockList\u0026rdquo; and \u0026ldquo;GlobalQueryBlockList.\u0026rdquo; This activity could indicate an attacker attempting to weaken defenses to facilitate further malicious activities.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system, possibly through compromised credentials or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to obtain DNSAdmin rights.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the \u0026ldquo;EnableGlobalQueryBlockList\u0026rdquo; registry value to \u0026ldquo;0\u0026rdquo; or \u0026ldquo;0x00000000,\u0026rdquo; effectively disabling the GQBL.\u003c/li\u003e\n\u003cli\u003eAlternatively, the attacker modifies the \u0026ldquo;GlobalQueryBlockList\u0026rdquo; registry value to remove \u0026ldquo;wpad\u0026rdquo; from the list.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the disabled GQBL to conduct WPAD spoofing attacks, redirecting network traffic to attacker-controlled servers.\u003c/li\u003e\n\u003cli\u003eThe attacker captures user credentials transmitted during WPAD authentication.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the captured credentials to move laterally to other systems on the network.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data exfiltration or deploying ransomware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification or disabling of the DNS Global Query Block List can lead to WPAD spoofing attacks, credential theft, lateral movement, and ultimately, complete compromise of the network. Attackers can leverage this technique to gain unauthorized access to sensitive data or systems. The impact includes potential data breaches, financial loss, and reputational damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eRegistry Modification of DNS Global Query Block List\u003c/code\u003e to your SIEM to detect unauthorized changes to the GQBL configuration.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to capture the necessary events for the Sigma rule to function (reference the logsource in the rule).\u003c/li\u003e\n\u003cli\u003eReview and restrict DNSAdmin privileges to only necessary accounts to minimize the attack surface (reference: Overview section).\u003c/li\u003e\n\u003cli\u003eMonitor network traffic for unusual DNS queries or WPAD-related activity, correlating with registry modification events (reference: Attack Chain step 5).\u003c/li\u003e\n\u003cli\u003eRegularly audit registry settings related to DNS configuration, including the GQBL, to identify unauthorized modifications (reference: Attack Chain steps 3 \u0026amp; 4).\u003c/li\u003e\n\u003cli\u003eUpdate security policies and procedures to include specific measures for monitoring and protecting the DNS Global Query Block List (reference: Impact section).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-07-03T10:00:00Z","date_published":"2024-07-03T10:00:00Z","id":"/briefs/2024-07-dns-gqbl-modified/","summary":"Attackers with DNSAdmin privileges can modify or disable the DNS Global Query Block List (GQBL) in Windows, allowing exploitation of hosts running WPAD with default settings for privilege escalation and lateral movement.","title":"DNS Global Query Block List Modified or Disabled","url":"https://feed.craftedsignal.io/briefs/2024-07-dns-gqbl-modified/"},{"_cs_actors":[],"_cs_cves":[{"cvss":10,"id":"CVE-2024-1709"},{"cvss":8.4,"id":"CVE-2024-1708"}],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","ScreenConnect"],"_cs_severities":["medium"],"_cs_tags":["command-and-control","defense-evasion","execution","persistence","screenconnect"],"_cs_type":"advisory","_cs_vendors":["Elastic"],"content_html":"\u003cp\u003eThis threat brief focuses on the detection of suspicious activities related to the ScreenConnect remote access tool. ScreenConnect is a legitimate remote support software, but adversaries can exploit it to execute unauthorized commands on compromised systems. This detection identifies suspicious child processes spawned by ScreenConnect client processes, such as \u003ccode\u003eScreenConnect.ClientService.exe\u003c/code\u003e or \u003ccode\u003eScreenConnect.WindowsClient.exe\u003c/code\u003e, which can indicate malicious activities such as spawning PowerShell or cmd.exe with unusual arguments. This activity can indicate potential abuse of remote access capabilities, leading to data exfiltration, command and control communication, or the establishment of persistence mechanisms. Recent exploitation of CVE-2024-1709 and CVE-2024-1708 have highlighted the risk associated with ScreenConnect exploitation.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains unauthorized access to a system with ScreenConnect installed. This could be achieved through exploiting vulnerabilities like CVE-2024-1709 and CVE-2024-1708, or through credential compromise.\u003c/li\u003e\n\u003cli\u003eThe attacker uses ScreenConnect to connect to the compromised system remotely.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the ScreenConnect interface to execute commands on the remote system.\u003c/li\u003e\n\u003cli\u003eThe attacker spawns a command interpreter, such as \u003ccode\u003ecmd.exe\u003c/code\u003e, using ScreenConnect. This process is a child process of the ScreenConnect client process.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003ecmd.exe\u003c/code\u003e to execute malicious commands, such as downloading and executing a malicious payload.\u003c/li\u003e\n\u003cli\u003eAlternatively, the attacker spawns \u003ccode\u003epowershell.exe\u003c/code\u003e with encoded commands or commands to download and execute malicious payloads from a remote server.\u003c/li\u003e\n\u003cli\u003eThe attacker establishes persistence by creating a scheduled task using \u003ccode\u003eschtasks.exe\u003c/code\u003e or creates a new service using \u003ccode\u003esc.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker uses tools like \u003ccode\u003enet.exe\u003c/code\u003e to modify user accounts or privileges to maintain access to the compromised system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to unauthorized access to sensitive data, installation of malware, and establishment of persistent access to the compromised system. This can result in data theft, disruption of services, and further lateral movement within the network. The number of victims and specific sectors targeted varies depending on the attacker\u0026rsquo;s objectives, but the impact can be significant for organizations relying on ScreenConnect for remote support.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rules provided in this brief to your SIEM to detect suspicious child processes spawned by ScreenConnect and tune for your environment.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for ScreenConnect client processes spawning suspicious child processes like \u003ccode\u003epowershell.exe\u003c/code\u003e, \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003enet.exe\u003c/code\u003e, \u003ccode\u003eschtasks.exe\u003c/code\u003e, \u003ccode\u003esc.exe\u003c/code\u003e, \u003ccode\u003erundll32.exe\u003c/code\u003e, \u003ccode\u003emshta.exe\u003c/code\u003e, \u003ccode\u003ecertutil.exe\u003c/code\u003e, \u003ccode\u003ewscript.exe\u003c/code\u003e, \u003ccode\u003ecscript.exe\u003c/code\u003e, \u003ccode\u003ecurl.exe\u003c/code\u003e, \u003ccode\u003essh.exe\u003c/code\u003e, \u003ccode\u003escp.exe\u003c/code\u003e, \u003ccode\u003ewevtutil.exe\u003c/code\u003e, \u003ccode\u003ewget.exe\u003c/code\u003e, or \u003ccode\u003ewmic.exe\u003c/code\u003e as detailed in the Sigma rules.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process-creation logging to capture the necessary process execution data to activate the rules above.\u003c/li\u003e\n\u003cli\u003eReview and revoke any unauthorized user accounts or privileges that may have been created or modified using tools like \u003ccode\u003enet.exe\u003c/code\u003e as described in the attack chain.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-05-16T16:10:00Z","date_published":"2024-05-16T16:10:00Z","id":"/briefs/2024-05-screenconnect-child-process/","summary":"This rule identifies suspicious child processes spawned by ScreenConnect client processes, potentially indicating unauthorized access and command execution abusing ScreenConnect remote access software to perform malicious activities such as data exfiltration or establishing persistence.","title":"Suspicious ScreenConnect Client Child Process Activity","url":"https://feed.craftedsignal.io/briefs/2024-05-screenconnect-child-process/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","Elastic Endgame","SentinelOne Cloud Funnel","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","lateral-movement","registry-modification","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eNetwork Level Authentication (NLA) is a security feature in Windows that requires users to authenticate before establishing a full RDP session, adding an extra layer of protection against unauthorized access. Attackers might attempt to disable NLA to gain access to the Windows sign-in screen without proper authentication. This tactic can facilitate the deployment of persistence mechanisms, such as leveraging Accessibility Features like Sticky Keys, or enable unauthorized remote access. This brief addresses the registry modifications associated with disabling NLA and provides detection strategies to identify such attempts. The references indicate that this technique is used in conjunction with other attacks for lateral movement within a compromised network.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial access to the system is gained (potentially via compromised credentials or vulnerability exploitation).\u003c/li\u003e\n\u003cli\u003eThe attacker elevates privileges to modify system-level settings.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the registry key \u003ccode\u003eHKLM\\SYSTEM\\ControlSet*\\Control\\Terminal Server\\WinStations\\RDP-Tcp\\UserAuthentication\u003c/code\u003e to disable NLA.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003eUserAuthentication\u003c/code\u003e value is set to \u0026ldquo;0\u0026rdquo; or \u0026ldquo;0x00000000\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to establish an RDP connection to the compromised system.\u003c/li\u003e\n\u003cli\u003eDue to the disabled NLA, the attacker bypasses the initial authentication screen.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages accessibility features (e.g., Sticky Keys) for persistence or further exploitation.\u003c/li\u003e\n\u003cli\u003eThe attacker gains unauthorized access to the system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful disabling of NLA allows attackers to bypass authentication and gain unauthorized access to systems via RDP. This can lead to data theft, malware installation, or further lateral movement within the network. While the exact number of victims and sectors targeted are unspecified, the potential impact includes significant data breaches and system compromise.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process-creation and registry event logging to detect the registry modifications (Elastic Defend, Elastic Endgame, Microsoft Defender XDR, SentinelOne, Sysmon).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule provided to detect attempts to modify the \u003ccode\u003eUserAuthentication\u003c/code\u003e registry key (Sysmon Registry Events).\u003c/li\u003e\n\u003cli\u003eReview and harden RDP configurations across the environment to prevent unauthorized access (Microsoft documentation).\u003c/li\u003e\n\u003cli\u003eMonitor endpoint security policies to detect unauthorized registry modifications (Endpoint Security Policies).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-31T12:00:00Z","date_published":"2024-01-31T12:00:00Z","id":"/briefs/2024-01-disable-nla/","summary":"Adversaries may disable Network-Level Authentication (NLA) by modifying specific registry keys to bypass authentication requirements for Remote Desktop Protocol (RDP) and enable persistence mechanisms.","title":"Network-Level Authentication (NLA) Disabled via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-disable-nla/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers often attempt to modify file or directory ownership to bypass access controls and gain unauthorized access to sensitive data or system resources. This involves altering permissions associated with critical files or directories, granting broader access to accounts under attacker control or resetting permissions to default values which might be more permissive. This defense evasion technique can be used to establish persistence, escalate privileges, or exfiltrate data without triggering standard security alerts. The common tools used include \u003ccode\u003eicacls.exe\u003c/code\u003e and \u003ccode\u003etakeown.exe\u003c/code\u003e, typically targeting files within the \u003ccode\u003eC:\\Windows\\\u003c/code\u003e directory.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial access is achieved through an existing compromised account or vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003etakeown.exe /f \u0026lt;file\u0026gt;\u003c/code\u003e to take ownership of a target file or directory.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003eicacls.exe \u0026lt;file\u0026gt; /reset\u003c/code\u003e to reset the ACL of the file or directory.\u003c/li\u003e\n\u003cli\u003eAlternatively, the attacker uses \u003ccode\u003eicacls.exe \u0026lt;file\u0026gt; /grant Everyone:F\u003c/code\u003e to grant full control to everyone, weakening security.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the contents of the file, such as injecting malicious code or configuration changes.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the modified file for persistence, such as a modified system DLL loaded at boot.\u003c/li\u003e\n\u003cli\u003eThe system executes the malicious code when the compromised file is accessed or executed.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as maintaining persistence, escalating privileges, or executing arbitrary commands.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eCompromising file and directory permissions can lead to significant security breaches. Successful attacks can allow unauthorized access to sensitive data, system instability, or the execution of malicious code with elevated privileges. This can affect any Windows environment where file permissions are improperly managed, with potential for widespread system compromise and data exfiltration. The impact is most severe on systems containing sensitive data or critical infrastructure components.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor process execution for \u003ccode\u003eicacls.exe\u003c/code\u003e and \u003ccode\u003etakeown.exe\u003c/code\u003e with suspicious arguments targeting system files (e.g., \u003ccode\u003eC:\\Windows\\*\u003c/code\u003e) to detect potential permission modification attempts using the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eEnable Windows Security Auditing for file system changes to capture events related to permission modifications and ownership changes.\u003c/li\u003e\n\u003cli\u003eDeploy the provided Sigma rules to your SIEM and tune for your environment, specifically focusing on processes modifying permissions on files within the \u003ccode\u003eC:\\Windows\\\u003c/code\u003e directory.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rules, focusing on the process execution chain and the target files being modified.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-30T12:00:00Z","date_published":"2024-01-30T12:00:00Z","id":"/briefs/2024-01-system-file-ownership-change/","summary":"Adversaries may modify file or directory ownership to evade access control lists (ACLs) and access protected files, often using icacls.exe or takeown.exe to reset permissions on system files.","title":"System File Ownership Change for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-system-file-ownership-change/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike Falcon","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["persistence","windows","netsh","registry"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThe \u003ccode\u003enetsh.exe\u003c/code\u003e utility in Windows supports the addition of Helper DLLs to extend its functionality. An attacker can abuse this mechanism to establish persistence by adding a malicious DLL. When \u003ccode\u003enetsh.exe\u003c/code\u003e is executed, the malicious DLL is loaded and executed, allowing the attacker to run arbitrary code with the privileges of the user or process that initiated \u003ccode\u003enetsh.exe\u003c/code\u003e. This can be done by administrators or scheduled tasks, making it a stealthy and effective persistence technique. The registry key targeted by this technique is \u003ccode\u003eHKLM\\Software\\Microsoft\\netsh\\\u003c/code\u003e.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker gains initial access to the target system through unspecified means.\u003c/li\u003e\n\u003cli\u003eAttacker creates a malicious DLL to be used as a Netsh Helper DLL.\u003c/li\u003e\n\u003cli\u003eAttacker modifies the Windows Registry to add the malicious DLL as a Netsh Helper DLL under \u003ccode\u003eHKLM\\Software\\Microsoft\\netsh\\\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe system administrator or a scheduled task executes \u003ccode\u003enetsh.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003enetsh.exe\u003c/code\u003e loads and executes the malicious DLL, granting the attacker code execution.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL performs its intended actions, such as establishing a reverse shell or deploying additional malware.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence on the system through the malicious Netsh Helper DLL.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to establish persistent access to a compromised system. This can lead to data theft, system compromise, and further malicious activities. While the risk score is low, the persistence mechanism can allow attackers to maintain a foothold for extended periods, increasing the potential for significant damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor registry modifications under the \u003ccode\u003eHKLM\\Software\\Microsoft\\netsh\\\u003c/code\u003e path for suspicious DLL additions using the \u0026ldquo;Netsh Helper DLL Registry Modification\u0026rdquo; Sigma rule.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to collect the necessary data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by reviewing the DLL file properties, timestamps, and related processes.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-30T12:00:00Z","date_published":"2024-01-30T12:00:00Z","id":"/briefs/2024-01-netsh-helper-dll/","summary":"Attackers may abuse the Netsh Helper DLL functionality by adding malicious DLLs to execute payloads every time the netsh utility is executed via administrators or scheduled tasks, achieving persistence.","title":"Netsh Helper DLL Persistence","url":"https://feed.craftedsignal.io/briefs/2024-01-netsh-helper-dll/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["credential-access","windows","vaultcmd"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers may abuse the Windows Credential Manager to list or dump credentials stored within. This allows for the exfiltration of saved usernames and passwords. The tool vaultcmd.exe can be used to interact with the Credential Manager and list the stored credentials. This activity is often performed in preparation for lateral movement within a compromised network. This detection focuses on identifying instances where vaultcmd.exe is executed with the \u003ccode\u003e/list*\u003c/code\u003e argument, indicating an attempt to enumerate stored credentials. The detection rule is designed to identify abuse of vaultcmd for credential access, enabling defenders to detect unauthorized credential access activities.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through various means (e.g., phishing, exploitation of a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003evaultcmd.exe\u003c/code\u003e with the \u003ccode\u003e/list\u003c/code\u003e argument to enumerate the credentials stored in the Windows Credential Manager.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003evaultcmd.exe\u003c/code\u003e process accesses the Credential Manager to retrieve the list of saved credentials.\u003c/li\u003e\n\u003cli\u003eThe output of \u003ccode\u003evaultcmd.exe\u003c/code\u003e (the list of credentials) is captured or redirected to a file for later exfiltration.\u003c/li\u003e\n\u003cli\u003eThe attacker parses the output to identify valuable credentials, such as domain administrator accounts or service accounts.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the acquired credentials to authenticate to other systems on the network (lateral movement).\u003c/li\u003e\n\u003cli\u003eThe attacker elevates privileges on the target systems.\u003c/li\u003e\n\u003cli\u003eThe final objective is achieved, such as data theft or ransomware deployment.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful execution of this attack chain can lead to unauthorized access to sensitive resources, lateral movement within the network, and ultimately, data theft, system compromise, or ransomware deployment. A compromised user account can grant the attacker access to internal systems, confidential data, and critical infrastructure. If the attacker gains domain administrator credentials, they can compromise the entire Windows domain.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor process execution events for instances of \u003ccode\u003evaultcmd.exe\u003c/code\u003e being executed with the \u003ccode\u003e/list*\u003c/code\u003e argument (Data Source: Windows Security Event Logs, Sysmon, Microsoft Defender XDR, SentinelOne, Crowdstrike).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect VaultCmd Credential Listing\u0026rdquo; to your SIEM to identify potential credential access attempts.\u003c/li\u003e\n\u003cli\u003eInvestigate any identified instances of \u003ccode\u003evaultcmd.exe\u003c/code\u003e being executed with the \u003ccode\u003e/list*\u003c/code\u003e argument to determine the legitimacy of the activity.\u003c/li\u003e\n\u003cli\u003eReview and update endpoint protection configurations to ensure that similar threats are detected and blocked in the future.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-29T12:00:00Z","date_published":"2024-01-29T12:00:00Z","id":"/briefs/2024-01-29-vaultcmd-credential-access/","summary":"Adversaries may use vaultcmd.exe to list credentials stored in the Windows Credential Manager to gain unauthorized access to saved usernames and passwords, potentially in preparation for lateral movement.","title":"VaultCmd Usage for Listing Windows Credentials","url":"https://feed.craftedsignal.io/briefs/2024-01-29-vaultcmd-credential-access/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","masquerading","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies processes executing from directories that masquerade as the legitimate Windows Program Files directories. Attackers may create directories with similar names (e.g., \u0026ldquo;C:\\Program Files Bad\u0026rdquo; or \u0026ldquo;C:\\Program Files(x86) Malicious\u0026rdquo;) to host and execute malicious executables, bypassing security measures that trust the standard Program Files locations. This technique is particularly effective when combined with low-privilege accounts, as it allows attackers to evade detections that whitelist only the standard, trusted Program Files paths. The timeframe for this rule is the last 9 months. This matters to defenders because it highlights a common tactic used to bypass established trust relationships within the Windows operating system, requiring more granular inspection of process execution paths.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system, potentially through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker creates a new directory that mimics the \u0026ldquo;Program Files\u0026rdquo; or \u0026ldquo;Program Files (x86)\u0026rdquo; directory (e.g., \u0026ldquo;C:\\Program Files Bad\u0026rdquo;).\u003c/li\u003e\n\u003cli\u003eThe attacker copies or downloads malicious executable files into the newly created masquerading directory.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the malicious executable from the masquerading directory.\u003c/li\u003e\n\u003cli\u003eThe operating system loads the executable and begins its execution, potentially bypassing any allowlisting rules that only check the standard \u0026ldquo;Program Files\u0026rdquo; locations.\u003c/li\u003e\n\u003cli\u003eThe malicious executable performs its intended actions, such as installing malware, establishing persistence, or exfiltrating data.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the compromised system to move laterally within the network, repeating the masquerading technique on other systems.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to malware infection, data theft, or complete system compromise. The impact is significant, as it undermines the trust placed in the \u0026ldquo;Program Files\u0026rdquo; directory and allows attackers to operate undetected for extended periods. While no specific victim counts are given, the technique is broadly applicable to any Windows environment, especially those relying on simple path-based allowlisting for security.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eProgram Files Directory Masquerading Detection\u003c/code\u003e to your SIEM to detect suspicious process executions from masquerading directories.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to collect the necessary process execution data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eRegularly review and update allowlisting rules to include more specific criteria beyond just the \u0026ldquo;Program Files\u0026rdquo; directory, such as file hashes or digital signatures.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the parent processes and user accounts associated with the suspicious executions.\u003c/li\u003e\n\u003cli\u003eMonitor file creation events in the root directory to detect suspicious folders being created (file_event category)\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-29T12:00:00Z","date_published":"2024-01-29T12:00:00Z","id":"/briefs/2024-01-program-files-masquerading/","summary":"Adversaries may masquerade malicious executables within directories mimicking the legitimate Windows Program Files directory to evade defenses and execute untrusted code.","title":"Program Files Directory Masquerading","url":"https://feed.craftedsignal.io/briefs/2024-01-program-files-masquerading/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Defend","Elastic Endgame"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","windows","msiexec","remote-install"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAdversaries may abuse Windows Installer (msiexec.exe) to perform remote installations of malicious payloads. This technique is used for initial access, defense evasion, and execution of arbitrary code. The detection rule identifies attempts to install a file from a remote server using MsiExec. The rule looks for msiexec.exe processes running with arguments such as \u003ccode\u003e-i\u003c/code\u003e, \u003ccode\u003e/i\u003c/code\u003e, \u003ccode\u003e-p\u003c/code\u003e, or \u003ccode\u003e/p\u003c/code\u003e, indicative of remote installations, and executed from suspicious parent processes like \u003ccode\u003esihost.exe\u003c/code\u003e, \u003ccode\u003eexplorer.exe\u003c/code\u003e, \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003ewscript.exe\u003c/code\u003e, \u003ccode\u003emshta.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e, \u003ccode\u003ewmiprvse.exe\u003c/code\u003e, \u003ccode\u003epcalua.exe\u003c/code\u003e, \u003ccode\u003eforfiles.exe\u003c/code\u003e, and \u003ccode\u003econhost.exe\u003c/code\u003e. The rule includes exceptions to reduce false positives from legitimate software installations, specifically excluding command lines containing \u003ccode\u003e--set-server\u003c/code\u003e, \u003ccode\u003eUPGRADEADD\u003c/code\u003e, \u003ccode\u003e--url\u003c/code\u003e, \u003ccode\u003eUSESERVERCONFIG\u003c/code\u003e, \u003ccode\u003eRCTENTERPRISESERVER\u003c/code\u003e, \u003ccode\u003eapp.ninjarmm.com\u003c/code\u003e, \u003ccode\u003ezoom.us/client\u003c/code\u003e, \u003ccode\u003eSUPPORTSERVERSTSURI\u003c/code\u003e, \u003ccode\u003eSTART_URL\u003c/code\u003e, \u003ccode\u003eAUTOCONFIG\u003c/code\u003e, \u003ccode\u003eawscli.amazonaws.com\u003c/code\u003e, \u003ccode\u003e*/i \\\u0026quot;C:*\u003c/code\u003e, and \u003ccode\u003e*/i C:\\\\*\u003c/code\u003e. This technique can lead to complete system compromise and data exfiltration.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access via an unspecified method (e.g., phishing, exploit).\u003c/li\u003e\n\u003cli\u003eThe attacker uses a script or command-line interpreter (e.g., \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e) to initiate the \u003ccode\u003emsiexec.exe\u003c/code\u003e process.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003emsiexec.exe\u003c/code\u003e process is launched with arguments that specify a remote MSI package (\u003ccode\u003e-i\u003c/code\u003e, \u003ccode\u003e/i\u003c/code\u003e, \u003ccode\u003e-p\u003c/code\u003e, \u003ccode\u003e/p\u003c/code\u003e) and enable silent installation (\u003ccode\u003e/qn\u003c/code\u003e, \u003ccode\u003e-qn\u003c/code\u003e, \u003ccode\u003e-q\u003c/code\u003e, \u003ccode\u003e/q\u003c/code\u003e, \u003ccode\u003e/quiet\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003emsiexec.exe\u003c/code\u003e process downloads the MSI package from a remote server over HTTP or HTTPS.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003emsiexec.exe\u003c/code\u003e executes the downloaded MSI package, which may contain malicious payloads.\u003c/li\u003e\n\u003cli\u003eThe malicious payload executes, potentially performing actions such as installing malware, establishing persistence, or escalating privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker gains control over the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker performs further actions, such as data exfiltration or lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to arbitrary code execution, allowing attackers to install malware, steal sensitive data, or disrupt system operations. A compromised system can be used as a pivot point to access other systems on the network. The impact can range from data breaches and financial losses to reputational damage and disruption of critical services. The number of potential victims depends on the scope of the initial access and the attacker\u0026rsquo;s objectives.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rule to your SIEM to detect suspicious MsiExec invocations with remote payloads.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to ensure the required data is available for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the parent process, command-line arguments, and network connections associated with the \u003ccode\u003emsiexec.exe\u003c/code\u003e process.\u003c/li\u003e\n\u003cli\u003eMonitor process execution events for child processes spawned by \u003ccode\u003emsiexec.exe\u003c/code\u003e for anomalous activity.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of \u003ccode\u003emsiexec.exe\u003c/code\u003e to authorized users and processes only.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-29T10:00:00Z","date_published":"2024-01-29T10:00:00Z","id":"/briefs/2024-01-29-msiexec-remote-payload/","summary":"This rule detects attempts to install a file from a remote server using MsiExec, which adversaries may abuse to deliver malware, by identifying msiexec.exe processes running with arguments indicative of remote installations and executed from suspicious parent processes.","title":"Potential Remote Install via MsiExec","url":"https://feed.craftedsignal.io/briefs/2024-01-29-msiexec-remote-payload/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel","Elastic Endgame","Sysmon"],"_cs_severities":["low"],"_cs_tags":["privilege-escalation","unquoted-service-path","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","CrowdStrike","SentinelOne"],"content_html":"\u003cp\u003eUnquoted service paths in Windows can be exploited to escalate privileges. When a service path lacks quotes, Windows may execute a malicious executable placed in a higher-level directory. This detection rule identifies suspicious processes starting from common unquoted paths, like \u0026ldquo;C:\\Program.exe\u0026rdquo; or executables within \u0026ldquo;C:\\Program Files (x86)\\\u0026rdquo; or \u0026ldquo;C:\\Program Files\\\u0026rdquo;, signaling potential exploitation attempts. The rule aims to detect early stages of privilege escalation threats. This rule is designed for data generated by Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, Sysmon, Windows Security Event Logs, and Crowdstrike.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker identifies a service running with an unquoted path, such as \u0026ldquo;C:\\Program Files\\Unquoted Path Service\\Common\\Service.exe\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eThe attacker places a malicious executable named \u0026ldquo;Program.exe\u0026rdquo; in \u0026ldquo;C:\u0026quot;\u003c/li\u003e\n\u003cli\u003eThe operating system attempts to start the service \u0026ldquo;C:\\Program Files\\Unquoted Path Service\\Common\\Service.exe\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eDue to the unquoted path, the OS incorrectly parses the path and first attempts to execute \u0026ldquo;C:\\Program.exe\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eThe malicious \u0026ldquo;Program.exe\u0026rdquo; executes with the privileges of the service account.\u003c/li\u003e\n\u003cli\u003eThe malicious executable performs actions to escalate privileges, such as adding a user to the local administrators group.\u003c/li\u003e\n\u003cli\u003eThe attacker gains elevated access to the system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of an unquoted service path vulnerability can lead to complete system compromise, as the attacker gains the privileges of the service account. This can allow the attacker to install programs, view, change, or delete data, or create new accounts with full user rights. The impact is high, potentially leading to a loss of confidentiality, integrity, and availability of the affected system.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eReview process executable paths to confirm if they match the patterns specified in the rule query, such as \u0026ldquo;?:\\Program.exe\u0026rdquo; or executables within \u0026ldquo;C:\\Program Files (x86)\\\u0026rdquo; or \u0026ldquo;C:\\Program Files\\\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Potential Exploitation of an Unquoted Service Path Vulnerability\u0026rdquo; to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process-creation logging with Event ID 1 to activate the Sigma rules above.\u003c/li\u003e\n\u003cli\u003eConduct a thorough review of service configurations to identify and correct any unquoted service paths as part of remediation steps.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-29T10:00:00Z","date_published":"2024-01-29T10:00:00Z","id":"/briefs/2024-01-29-unquoted-service-path/","summary":"This rule detects potential exploitation of unquoted service path vulnerabilities, where adversaries may escalate privileges by placing a malicious executable in a higher-level directory within the path of an unquoted service executable.","title":"Potential Exploitation of an Unquoted Service Path Vulnerability","url":"https://feed.craftedsignal.io/briefs/2024-01-29-unquoted-service-path/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Sysmon Event ID 1 - Process Creation","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["lolbin","command-and-control","exfiltration","certreq"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThe Windows Certreq utility is a command-line tool used for managing certificates. Adversaries may abuse Certreq to download files from or upload data to a remote server by initiating an HTTP POST request. This behavior can be used for command and control (C2) or exfiltration. This technique leverages a legitimate system binary (LOLBin) to evade detection. Elastic has observed this behavior being detected through multiple data sources including Elastic Defend, Microsoft Defender XDR, Sysmon, SentinelOne, and Crowdstrike. This is a cross-industry threat that can affect any organization using Windows.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes Certreq.exe with the \u003ccode\u003e-Post\u003c/code\u003e argument to initiate an HTTP POST request.\u003c/li\u003e\n\u003cli\u003eThe Certreq process attempts to connect to a remote server to send or receive data.\u003c/li\u003e\n\u003cli\u003eThe remote server responds to the Certreq request, potentially delivering a file or receiving exfiltrated data.\u003c/li\u003e\n\u003cli\u003eThe downloaded file is saved to disk (if applicable).\u003c/li\u003e\n\u003cli\u003eThe attacker may execute the downloaded file or further process the exfiltrated data.\u003c/li\u003e\n\u003cli\u003eThe attacker may attempt to clean up the Certreq command from command history or logs to evade detection.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation could lead to the download and execution of malicious payloads, potentially compromising the affected system and network. Alternatively, sensitive data could be exfiltrated from the target environment. The impact can range from data theft and system compromise to full network intrusion, depending on the attacker\u0026rsquo;s objectives and the data accessed. The severity is medium because Certreq is a legitimate tool, and its abuse requires specific command-line arguments and network activity.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Certreq HTTP Post Request\u0026rdquo; to your SIEM to identify potential abuse of Certreq for file transfer.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture the execution of Certreq.exe and its command-line arguments, enabling detections.\u003c/li\u003e\n\u003cli\u003eMonitor network connections originating from Certreq.exe for unusual destinations or data transfer patterns using network connection logs.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of Certreq.exe executing with the \u003ccode\u003e-Post\u003c/code\u003e argument, as this is not typical usage of the utility.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-28T20:47:00Z","date_published":"2024-01-28T20:47:00Z","id":"/briefs/2024-01-certreq-post/","summary":"Adversaries may abuse the Windows Certreq utility to download files or upload data to a remote URL by making an HTTP POST request, potentially for command and control or exfiltration, which can be detected by monitoring process execution events.","title":"Potential Abuse of Certreq for File Transfer via HTTP POST","url":"https://feed.craftedsignal.io/briefs/2024-01-certreq-post/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Endpoint Security","SentinelOne Cloud Funnel","Crowdstrike FDR","Sysmon"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","amsi","registry","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers can disable the Antimalware Scan Interface (AMSI) to evade detection by modifying the \u003ccode\u003eAmsiEnable\u003c/code\u003e registry key. This technique is commonly employed to execute malicious scripts without triggering security warnings or blocks. The AMSI, a Windows feature, allows applications and services to request the scanning of potentially malicious content (e.g., PowerShell scripts, JScript) before execution. By setting the \u003ccode\u003eAmsiEnable\u003c/code\u003e value to 0, an attacker can disable AMSI for the current user, effectively bypassing real-time script scanning. This action is often a precursor to deploying further malicious payloads or establishing persistence on a compromised system. This behavior has been observed since at least 2019 and continues to be a relevant defense evasion technique.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the target system, possibly through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker executes a script or binary that attempts to modify the \u003ccode\u003eAmsiEnable\u003c/code\u003e registry key.\u003c/li\u003e\n\u003cli\u003eThe script or binary uses \u003ccode\u003ereg.exe\u003c/code\u003e, PowerShell, or another tool to set the \u003ccode\u003eAmsiEnable\u003c/code\u003e registry value to 0. The registry key location is typically \u003ccode\u003eHKEY_USERS\\\u0026lt;SID\u0026gt;\\Software\\Microsoft\\Windows Script\\Settings\\AmsiEnable\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eAfter successfully disabling AMSI, the attacker proceeds to execute malicious scripts or code. These scripts may use \u003ccode\u003epowershell.exe\u003c/code\u003e, \u003ccode\u003ewscript.exe\u003c/code\u003e, or \u003ccode\u003ecscript.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe malicious scripts download and execute additional payloads, such as malware or remote access tools (RATs).\u003c/li\u003e\n\u003cli\u003eThe attacker performs lateral movement within the network using the compromised system as a pivot.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to establish persistence, ensuring continued access to the system even after reboots.\u003c/li\u003e\n\u003cli\u003eThe attacker exfiltrates sensitive data or deploys ransomware to achieve their objectives.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of the \u003ccode\u003eAmsiEnable\u003c/code\u003e registry key allows attackers to execute malicious scripts without triggering AMSI alerts, leading to potential malware infections, data breaches, and system compromise. Disabling AMSI significantly reduces the effectiveness of endpoint security solutions, making the system more vulnerable to attack. The impact can range from individual workstation compromise to widespread network infections, depending on the attacker\u0026rsquo;s objectives and the organization\u0026rsquo;s security posture.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect AmsiEnable Registry Modification via Registry Events\u003c/code\u003e to your SIEM to detect modifications to the \u003ccode\u003eAmsiEnable\u003c/code\u003e registry key.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to provide the necessary data for the Sigma rule to function.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for processes modifying registry keys, especially \u003ccode\u003ereg.exe\u003c/code\u003e and PowerShell, using the rule \u003ccode\u003eDetect AmsiEnable Registry Modification via Process Creation\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by these rules promptly to determine if the activity is malicious or legitimate.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of unsigned or untrusted scripts and binaries.\u003c/li\u003e\n\u003cli\u003eHarden systems by restricting user permissions to modify critical registry keys.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-27T18:23:00Z","date_published":"2024-01-27T18:23:00Z","id":"/briefs/2024-01-amsi-registry-disable/","summary":"Adversaries modify the AmsiEnable registry key to 0 to disable Windows Script AMSI scanning, bypassing AMSI protections for Windows Script Host or JScript execution.","title":"AMSI Enable Registry Key Modification for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-amsi-registry-disable/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Office","Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Crowdstrike"],"_cs_severities":["low"],"_cs_tags":["persistence","registry","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThe \u0026ldquo;Office Test\u0026rdquo; registry key, located under \u003ccode\u003eHKCU\\Software\\Microsoft\\Office Test\\Special\\Perf\u003c/code\u003e, is a legitimate feature that allows specifying a DLL to be executed every time an MS Office application is started. Attackers can abuse this functionality by modifying the registry to point to a malicious DLL, achieving persistence on a compromised host. This allows for continued malicious activity even after a system restart or user logout. Elastic has published a rule to detect this behavior. The modification of this registry key, excluding deletions, is a strong indicator of potential abuse, and can be detected via endpoint detection and response (EDR) solutions as well as traditional Sysmon logging.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system, often through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker establishes a foothold and escalates privileges to make necessary registry modifications.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the \u003ccode\u003eHKCU\\Software\\Microsoft\\Office Test\\Special\\Perf\u003c/code\u003e registry key, adding a new entry or modifying an existing one to point to a malicious DLL.\u003c/li\u003e\n\u003cli\u003eThe attacker ensures the malicious DLL is present on the system, either by dropping it directly or using existing system tools to download it.\u003c/li\u003e\n\u003cli\u003eA user launches a Microsoft Office application (e.g., Word, Excel, PowerPoint).\u003c/li\u003e\n\u003cli\u003eThe Office application loads the DLL specified in the \u0026ldquo;Office Test\u0026rdquo; registry key during startup.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL executes its payload, which could include establishing a reverse shell, installing malware, or exfiltrating data.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence, allowing them to regain access to the system each time an Office application is started.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to maintain persistent access to a compromised system. The injected DLL can be used to execute arbitrary code, potentially leading to data theft, malware installation, or further compromise of the network. The relatively low risk score suggests a common technique, but the potential for persistent access makes it a significant threat.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rule to your SIEM and tune for your environment to detect unauthorized modifications to the \u0026ldquo;Office Test\u0026rdquo; registry key (\u003ccode\u003eHKCU\\Software\\Microsoft\\Office Test\\Special\\Perf\\*\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Registry event logging to capture registry modifications and activate the Sigma rule above.\u003c/li\u003e\n\u003cli\u003eMonitor process execution logs for Office applications to detect if a suspicious DLL has been loaded or executed, as described in the investigation guide.\u003c/li\u003e\n\u003cli\u003eImplement enhanced monitoring and alerting for similar registry modifications across the network, as described in the remediation steps.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-27T17:30:00Z","date_published":"2024-01-27T17:30:00Z","id":"/briefs/2024-01-office-test-registry-persistence/","summary":"Attackers modify the Microsoft Office 'Office Test' Registry key to achieve persistence by specifying a malicious DLL that executes upon application startup.","title":"Microsoft Office 'Office Test' Registry Persistence Abuse","url":"https://feed.craftedsignal.io/briefs/2024-01-office-test-registry-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows","Elastic Defend","Microsoft Defender XDR"],"_cs_severities":["medium"],"_cs_tags":["persistence","execution","privilege_escalation","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eAttackers may configure existing Windows services or create new ones to execute system shells, in order to elevate their privileges from administrator to SYSTEM. This tactic is used to gain SYSTEM permissions and establish persistence. The detection rule focuses on identifying instances where \u003ccode\u003eservices.exe\u003c/code\u003e is the parent process of a command shell (cmd.exe, powershell.exe, pwsh.exe, powershell_ise.exe), indicating that a service is being abused to run a shell. The rule is designed to work with data from Elastic Defend, CrowdStrike, Microsoft Defender XDR, SentinelOne Cloud Funnel, Sysmon, and Windows Security Event Logs.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker gains initial access to the system with administrator privileges.\u003c/li\u003e\n\u003cli\u003eAttacker identifies a legitimate service or creates a new service to abuse for privilege escalation.\u003c/li\u003e\n\u003cli\u003eAttacker modifies the service configuration to execute a command shell (cmd.exe, powershell.exe, pwsh.exe, or powershell_ise.exe). This may involve modifying the service\u0026rsquo;s executable path or adding command-line arguments.\u003c/li\u003e\n\u003cli\u003eThe system\u0026rsquo;s Service Control Manager (SCM) starts the service.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003eservices.exe\u003c/code\u003e spawns the configured command shell process.\u003c/li\u003e\n\u003cli\u003eThe command shell executes with SYSTEM privileges.\u003c/li\u003e\n\u003cli\u003eAttacker uses the SYSTEM shell to perform malicious activities, such as installing malware, accessing sensitive data, or creating new user accounts.\u003c/li\u003e\n\u003cli\u003eThe service continues to run, providing persistent access to the system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation leads to privilege escalation to SYSTEM, granting the attacker complete control over the compromised system. This can result in data theft, malware installation, or further lateral movement within the network. The rule has a risk score of 47 and is categorized as medium severity.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSystem Shells via Services\u003c/code\u003e to detect the execution of command shells spawned by \u003ccode\u003eservices.exe\u003c/code\u003e within your SIEM environment, and tune for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any process creation events where \u003ccode\u003eservices.exe\u003c/code\u003e is the parent process of \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e, \u003ccode\u003epwsh.exe\u003c/code\u003e, or \u003ccode\u003epowershell_ise.exe\u003c/code\u003e using the investigation guide provided in the content section.\u003c/li\u003e\n\u003cli\u003eReview service creation and modification events in Windows Event Logs (Event IDs 4697 and 7045) for suspicious entries.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture detailed process information.\u003c/li\u003e\n\u003cli\u003eUtilize osquery to retrieve detailed service information to identify potentially malicious services. Reference queries $osquery_0, $osquery_1, and $osquery_2 in the investigation guide.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-26T12:00:00Z","date_published":"2024-01-26T12:00:00Z","id":"/briefs/2024-01-system-shells-via-services/","summary":"Attackers may configure existing services or create new ones to execute system shells to elevate their privileges from administrator to SYSTEM, using services.exe as the parent process of the shell.","title":"System Shells Launched via Windows Services","url":"https://feed.craftedsignal.io/briefs/2024-01-system-shells-via-services/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","Windows Error Reporting"],"_cs_severities":["medium"],"_cs_tags":["credential-access","windows","lsass","wepw"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eThe LSASS Shtinkering attack involves abusing Windows Error Reporting (WER) to dump the memory of the LSASS process, which contains sensitive credentials. By enabling full user-mode dumps system-wide, attackers can fake a crash on LSASS, causing WER to generate a dump file. This setting is not enabled by default and requires modifying the registry. The DeepInstinct researchers publicized this attack at Defcon 30, demonstrating a method to access credentials without directly injecting malware into the LSASS process. This technique allows attackers to bypass traditional endpoint detection mechanisms that focus on malware signatures, making it a stealthy approach to credential theft. Defenders should monitor for registry modifications related to WER dump settings to detect and prevent this attack.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system, potentially through phishing or exploitation of a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the registry key \u003ccode\u003eHKLM\\SOFTWARE\\Microsoft\\Windows\\Windows Error Reporting\\LocalDumps\\DumpType\u003c/code\u003e to the value \u003ccode\u003e2\u003c/code\u003e or \u003ccode\u003e0x00000002\u003c/code\u003e to enable full user-mode dumps system-wide.\u003c/li\u003e\n\u003cli\u003eThe attacker triggers a crash or fakes a crash of the LSASS process.\u003c/li\u003e\n\u003cli\u003eWindows Error Reporting (WER) generates a full user-mode dump file of the LSASS process.\u003c/li\u003e\n\u003cli\u003eThe dump file is stored in the location specified in the registry, typically \u003ccode\u003eC:\\ProgramData\\Microsoft\\Windows\\WER\\ReportQueue\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker accesses the generated dump file.\u003c/li\u003e\n\u003cli\u003eThe attacker extracts credentials from the LSASS dump file using tools like Mimikatz or custom scripts.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the stolen credentials to move laterally within the network or access sensitive resources.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to the compromise of domain credentials and other sensitive information stored in LSASS memory, such as NTLM hashes and Kerberos tickets. This can enable attackers to move laterally within the network, escalate privileges, and access critical systems and data. A single compromised system can lead to a widespread breach affecting numerous users and systems. The sectors most vulnerable are those handling sensitive data or critical infrastructure.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Full User-Mode Dumps Enabled System-Wide\u0026rdquo; to your SIEM to detect suspicious registry modifications related to Windows Error Reporting (WER).\u003c/li\u003e\n\u003cli\u003eExamine process execution logs to identify any suspicious processes that may have triggered the dump, especially those not matching the legitimate \u003ccode\u003esvchost.exe\u003c/code\u003e process with user IDs \u003ccode\u003eS-1-5-18\u003c/code\u003e, \u003ccode\u003eS-1-5-19\u003c/code\u003e, or \u003ccode\u003eS-1-5-20\u003c/code\u003e as described in the rule\u0026rsquo;s investigation guide.\u003c/li\u003e\n\u003cli\u003eMonitor for access to WER dump files located in \u003ccode\u003eC:\\ProgramData\\Microsoft\\Windows\\WER\\ReportQueue\u003c/code\u003e using file monitoring rules.\u003c/li\u003e\n\u003cli\u003eReview and update endpoint protection configurations to ensure they can detect and block credential dumping techniques as mentioned in the rule\u0026rsquo;s response and remediation steps.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-26T12:00:00Z","date_published":"2024-01-26T12:00:00Z","id":"/briefs/2024-01-26-lsass-shtinkering/","summary":"Attackers can enable full user-mode dumps system-wide via registry modification to facilitate LSASS credential dumping, allowing extraction of credentials from process memory without deploying malware.","title":"LSASS Credential Dumping via Windows Error Reporting (WER) Abuse","url":"https://feed.craftedsignal.io/briefs/2024-01-26-lsass-shtinkering/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["persistence","browser-extension","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne"],"content_html":"\u003cp\u003eThis detection rule identifies the installation of browser extensions on Windows systems, which can be a sign of malicious activity. Threat actors may install malicious browser extensions through app store downloads disguised as legitimate extensions, social engineering tactics, or by directly compromising a system. These extensions can then be used for persistence, data theft, or other malicious purposes. The rule focuses on monitoring file creation events related to browser extension installations, specifically targeting the file paths and types associated with Firefox (.xpi) and Chromium-based browsers (.crx). It excludes known safe processes and extensions to reduce false positives. This detection is relevant for defenders because malicious browser extensions can provide a persistent foothold for attackers, allowing them to maintain access to compromised systems and user data. The rule is based on EQL and can be used with Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon data.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe user\u0026rsquo;s system is compromised, potentially through social engineering or existing malware.\u003c/li\u003e\n\u003cli\u003eThe attacker gains access to the system and attempts to install a malicious browser extension.\u003c/li\u003e\n\u003cli\u003eThe attacker drops the extension file (.xpi for Firefox, .crx for Chromium) into the appropriate browser extension directory (e.g., \u003ccode\u003eC:\\\\Users\\\\*\\\\AppData\\\\Roaming\\\\*\\\\Profiles\\\\*\\\\Extensions\\\\\u003c/code\u003e for Firefox or \u003ccode\u003eC:\\\\Users\\\\*\\\\AppData\\\\Local\\\\*\\\\*\\\\User Data\\\\Webstore Downloads\\\\\u003c/code\u003e for Chromium).\u003c/li\u003e\n\u003cli\u003eA file creation event is triggered as the extension file is created in the target directory.\u003c/li\u003e\n\u003cli\u003eThe detection rule identifies this file creation event based on the file name and path, filtering out known safe processes like firefox.exe.\u003c/li\u003e\n\u003cli\u003eThe malicious extension installs itself into the browser.\u003c/li\u003e\n\u003cli\u003eThe extension gains persistence by loading every time the browser starts.\u003c/li\u003e\n\u003cli\u003eThe attacker can now perform malicious actions such as monitoring browsing activity, stealing credentials, or injecting malicious content into web pages.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack using malicious browser extensions can lead to persistent access to the compromised system, allowing attackers to steal sensitive information such as credentials, financial data, or personal information. This can result in financial loss, identity theft, and reputational damage. The installation of malicious extensions can also lead to the injection of malicious content into web pages, redirecting users to phishing sites or distributing malware. The scope of the impact can range from individual users to entire organizations, depending on the extent of the compromise.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) logging to capture the necessary file creation events for this detection.\u003c/li\u003e\n\u003cli\u003eDeploy the provided Sigma rule \u003ccode\u003eBrowser Extension Install via File Creation\u003c/code\u003e to your SIEM and tune the exclusions for your specific environment.\u003c/li\u003e\n\u003cli\u003eReview and update the list of known safe processes and extensions in the Sigma rule \u003ccode\u003eBrowser Extension Install via File Creation\u003c/code\u003e to minimize false positives.\u003c/li\u003e\n\u003cli\u003eImplement application whitelisting policies to restrict the installation of unauthorized browser extensions.\u003c/li\u003e\n\u003cli\u003eEducate users on the risks associated with installing browser extensions from untrusted sources and encourage them to only install extensions from official browser stores.\u003c/li\u003e\n\u003cli\u003eImplement policies to regularly review installed browser extensions across the organization.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-26T12:00:00Z","date_published":"2024-01-26T12:00:00Z","id":"/briefs/2024-01-browser-extension-install/","summary":"This rule identifies the installation of potentially malicious browser extensions, which adversaries can leverage for persistence and unauthorized activity by monitoring file creation events in common browser extension directories on Windows systems.","title":"Detection of Malicious Browser Extension Installation","url":"https://feed.craftedsignal.io/briefs/2024-01-browser-extension-install/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Diagnostics Troubleshooting Wizard (MSDT)","Microsoft Defender XDR"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","msdt","windows"],"_cs_type":"threat","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eThe Microsoft Diagnostics Troubleshooting Wizard (MSDT) is a built-in Windows tool used for troubleshooting various system issues. Attackers can abuse MSDT to proxy malicious command or binary execution through carefully crafted process arguments, evading traditional defense mechanisms. This technique leverages the trust associated with a signed Microsoft binary (msdt.exe) to execute arbitrary commands. The detection rule identifies suspicious MSDT executions based on command-line arguments, filename discrepancies, and unusual process relationships. This activity has been observed since at least May 2022 and continues to be a relevant defense evasion technique. Defenders should monitor for unusual invocations of MSDT, especially when launched from untrusted sources or with suspicious arguments.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker gains initial access via an unspecified vector (e.g., phishing, drive-by download).\u003c/li\u003e\n\u003cli\u003eThe attacker uses a malicious document or script to invoke \u003ccode\u003emsdt.exe\u003c/code\u003e with specific arguments.\u003c/li\u003e\n\u003cli\u003eMSDT is executed with a crafted \u003ccode\u003eIT_RebrowseForFile\u003c/code\u003e or \u003ccode\u003eIT_BrowseForFile\u003c/code\u003e parameter containing a malicious payload.\u003c/li\u003e\n\u003cli\u003eAlternatively, MSDT is executed with \u003ccode\u003e-af /skip\u003c/code\u003e and a path to a malicious \u003ccode\u003ePCWDiagnostic.xml\u003c/code\u003e file.\u003c/li\u003e\n\u003cli\u003eMSDT processes the malicious input, leading to the execution of attacker-controlled code.\u003c/li\u003e\n\u003cli\u003eThe attacker\u0026rsquo;s code executes, potentially downloading or executing further payloads.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves persistence by modifying registry keys or creating scheduled tasks.\u003c/li\u003e\n\u003cli\u003eThe attacker moves laterally through the network, compromising additional systems and data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to bypass security controls and execute arbitrary code on compromised systems. This can lead to data theft, system compromise, and further propagation of the attack within the network. The defense evasion tactic can obscure malicious activities, making it more difficult to detect and respond to incidents. Depending on the user\u0026rsquo;s privileges, the attacker might gain elevated privileges on the system.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rules to detect suspicious MSDT executions based on process arguments, filename discrepancies, and unusual parent-child relationships.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003emsdt.exe\u003c/code\u003e with arguments containing \u003ccode\u003eIT_RebrowseForFile=*\u003c/code\u003e, \u003ccode\u003e*FromBase64*\u003c/code\u003e, or \u003ccode\u003e*/../../../*\u003c/code\u003e using the provided Sigma rule.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture the necessary process execution details for the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by these rules, focusing on the process command line, parent process, and any spawned child processes.\u003c/li\u003e\n\u003cli\u003eBlock execution of \u003ccode\u003emsdt.exe\u003c/code\u003e from non-standard paths as highlighted in the detection rule.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-25T14:23:00Z","date_published":"2024-01-25T14:23:00Z","id":"/briefs/2024-01-25-msdt-abuse/","summary":"This rule detects potential abuse of the Microsoft Diagnostics Troubleshooting Wizard (MSDT) to proxy malicious command or binary execution via malicious process arguments on Windows systems.","title":"Suspicious Microsoft Diagnostics Wizard Execution","url":"https://feed.craftedsignal.io/briefs/2024-01-25-msdt-abuse/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel","Crowdstrike"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","execution","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection rule identifies anomalous creation or modification of executable files by critical Windows system processes, like \u003ccode\u003esmss.exe\u003c/code\u003e, \u003ccode\u003ecsrss.exe\u003c/code\u003e, and \u003ccode\u003elsass.exe\u003c/code\u003e. Attackers may attempt to leverage these processes to evade detection, and the rule is designed to detect such activities. The rule leverages data from Elastic Defend, Microsoft Defender XDR, SentinelOne, CrowdStrike, and Sysmon. It provides investigation steps to help analysts triage and analyze potential incidents, focusing on the identity of the writing process, its lineage, and the characteristics of the written file. This rule is designed to detect potential remote code execution or other forms of exploitation targeting Windows systems. The rule logic excludes specific legitimate file paths to minimize false positives.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system through methods such as phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker executes code on the system.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to escalate privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages a system critical process to create or modify an executable file.\u003c/li\u003e\n\u003cli\u003eThe created/modified file may be a backdoor, malware component, or a tool for further exploitation.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the created executable to establish persistence.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the newly created executable to perform lateral movement.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as data exfiltration or system compromise.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to arbitrary code execution with elevated privileges. The number of victims is dependent on the scope of the initial compromise. The targeted sectors include any organization running vulnerable Windows systems. If the attack succeeds, the adversary can gain full control over the system, leading to data theft, system disruption, or further propagation of malware.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Unusual Executable File Creation by a System Critical Process\u0026rdquo; detection rule to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon file creation logging (Event ID 11) to enhance detection capabilities (see setup instructions in the rule source).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by this rule, paying close attention to the writing process\u0026rsquo;s identity, lineage, and the characteristics of the written file as detailed in the rule\u0026rsquo;s triage and analysis section.\u003c/li\u003e\n\u003cli\u003eCorrelate alerts from this rule with other endpoint and network activity to identify the scope of the potential compromise.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-25T12:00:00Z","date_published":"2024-01-25T12:00:00Z","id":"/briefs/2024-01-25-unusual-executable-file-creation/","summary":"The rule identifies unexpected executable file creation or modification by critical Windows processes, potentially indicating remote code execution or exploitation attempts.","title":"Unusual Executable File Creation by a System Critical Process","url":"https://feed.craftedsignal.io/briefs/2024-01-25-unusual-executable-file-creation/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["exfiltration","credential-access","windows","smb","ntlm"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection strategy focuses on identifying unusual Server Message Block (SMB) traffic that originates from internal IP addresses and connects to external networks. The SMB protocol, commonly used for file and printer sharing within a network, can be exploited to exfiltrate data by injecting rogue UNC paths to capture NTLM credentials. This activity is often associated with threat actors attempting to steal credentials for lateral movement or data exfiltration. Defenders should be aware of this technique as it allows adversaries to bypass traditional security controls by leveraging a legitimate protocol for malicious purposes. This detection is relevant for environments utilizing Windows operating systems and SMB for internal network communications. The goal is to identify and alert on SMB connections to external IPs, excluding known safe ranges and legitimate business applications.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker compromises an internal system via phishing or other means (not detailed in source).\u003c/li\u003e\n\u003cli\u003eThe attacker injects a rogue UNC path into a document, email, or other medium.\u003c/li\u003e\n\u003cli\u003eA user opens the malicious document or clicks the injected link, triggering an SMB connection to a malicious external server.\u003c/li\u003e\n\u003cli\u003eThe SMB connection attempts to authenticate with the user\u0026rsquo;s NTLM credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker captures the NTLM hash from the authentication attempt.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to crack the NTLM hash to obtain the user\u0026rsquo;s password.\u003c/li\u003e\n\u003cli\u003eUsing the cracked password, the attacker gains unauthorized access to other systems and resources on the network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to credential theft, allowing attackers to gain unauthorized access to sensitive data and systems within the organization. This can result in data breaches, financial losses, and reputational damage. The impact is significant because SMB is a common protocol within many Windows environments, making this technique highly effective if not properly monitored.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect SMB Connection to External IP\u0026rdquo; to your SIEM to identify potentially malicious SMB connections to the internet. Tune the rule by excluding known good external IPs used by legitimate services.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 3 (Network Connection) with proper filtering to capture SMB traffic details as recommended in the linked setup guide, to enhance the fidelity of the detection.\u003c/li\u003e\n\u003cli\u003eImplement network segmentation to restrict SMB traffic to only necessary internal communications, reducing the attack surface and mitigating the risk of external exposure.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-25T12:00:00Z","date_published":"2024-01-25T12:00:00Z","id":"/briefs/2024-01-rare-smb-exfiltration/","summary":"This brief details a detection strategy for rare SMB connections originating from internal networks to the internet, potentially indicating NTLM credential theft via rogue UNC path injection.","title":"Detecting Rare SMB Connections for Potential NTLM Credential Theft","url":"https://feed.craftedsignal.io/briefs/2024-01-rare-smb-exfiltration/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","CrowdStrike"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","execution","masquerading","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft"],"content_html":"\u003cp\u003eAdversaries may use masquerading techniques to evade defenses and blend into the environment by manipulating the name or location of a file, tricking users into executing malicious code disguised as a benign file type. This rule detects the creation of executable files with multiple extensions, a common method of masquerading. The rule focuses on identifying suspicious file creations that use misleading extensions, specifically targeting files with an \u0026ldquo;.exe\u0026rdquo; extension preceded by common benign extensions. It excludes known legitimate processes to minimize false positives. This activity is relevant for defenders to identify potential threats where adversaries attempt to bypass security measures by disguising malicious files.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker crafts a malicious executable file with a double extension (e.g., \u0026ldquo;document.pdf.exe\u0026rdquo;).\u003c/li\u003e\n\u003cli\u003eThe attacker delivers the malicious file to the target system via phishing or other means.\u003c/li\u003e\n\u003cli\u003eThe user downloads or receives the file and attempts to open it.\u003c/li\u003e\n\u003cli\u003eWindows displays the file with the first extension (\u0026ldquo;document.pdf\u0026rdquo;) by default, misleading the user.\u003c/li\u003e\n\u003cli\u003eUpon execution, Windows recognizes the \u0026ldquo;.exe\u0026rdquo; extension and executes the file.\u003c/li\u003e\n\u003cli\u003eThe malicious executable runs, potentially deploying malware or performing other unauthorized actions.\u003c/li\u003e\n\u003cli\u003eThe malware establishes persistence or attempts lateral movement within the network.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as data theft or system compromise.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to malware infection, data breaches, and system compromise. This technique bypasses common file type restrictions and user awareness, potentially affecting a wide range of users and systems. While the number of victims is not specified, the impact can be significant, particularly in organizations where users handle sensitive data. The affected sectors are broad, encompassing any organization where users are susceptible to social engineering attacks.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Executable File Creation with Multiple Extensions\u0026rdquo; to your SIEM and tune for your environment to detect the creation of suspicious files with multiple extensions.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) for comprehensive file creation monitoring to improve the effectiveness of the detection rule.\u003c/li\u003e\n\u003cli\u003eImplement enhanced monitoring and logging for similar file creation activities to improve detection and response capabilities.\u003c/li\u003e\n\u003cli\u003eEducate users on the risks associated with double file extensions and encourage caution when opening attachments from unknown sources.\u003c/li\u003e\n\u003cli\u003eReview and whitelist legitimate software installations that may create executables with multiple extensions to reduce false positives, as described in the rule\u0026rsquo;s triage notes.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-24T12:00:00Z","date_published":"2024-01-24T12:00:00Z","id":"/briefs/2024-01-executable-file-creation-multiple-extensions/","summary":"Detection of executable files created with multiple extensions, a masquerading technique to evade defenses.","title":"Executable File Creation with Multiple Extensions","url":"https://feed.craftedsignal.io/briefs/2024-01-executable-file-creation-multiple-extensions/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Endgame","Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Sysmon","Windows Security Event Logs","Crowdstrike"],"_cs_severities":["high"],"_cs_tags":["credential-access","registry-dump","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies attempts to export registry hives containing sensitive credential information using the Windows \u003ccode\u003ereg.exe\u003c/code\u003e utility. Attackers may target the \u003ccode\u003eHKLM\\SAM\u003c/code\u003e and \u003ccode\u003eHKLM\\SECURITY\u003c/code\u003e hives to extract stored credentials, including password hashes and LSA secrets. The activity is often part of a broader credential access campaign. The rule focuses on detecting the execution of \u003ccode\u003ereg.exe\u003c/code\u003e with specific arguments indicating an attempt to save or export these critical registry hives. The use of \u003ccode\u003ereg.exe\u003c/code\u003e makes this technique accessible to various threat actors, including ransomware groups and nation-state actors. Defenders need to monitor for this activity to prevent unauthorized credential access and potential lateral movement within the network. This rule specifically looks for \u0026ldquo;save\u0026rdquo; and \u0026ldquo;export\u0026rdquo; arguments targeting SAM and SECURITY hives.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system, potentially through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003ereg.exe\u003c/code\u003e from the command line or through a script.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003ereg.exe\u003c/code\u003e command includes arguments to save or export registry hives.\u003c/li\u003e\n\u003cli\u003eThe target registry hives are \u003ccode\u003eHKLM\\SAM\u003c/code\u003e and \u003ccode\u003eHKLM\\SECURITY\u003c/code\u003e, containing sensitive credential information.\u003c/li\u003e\n\u003cli\u003eThe exported registry hive is saved to a file on disk or a network share.\u003c/li\u003e\n\u003cli\u003eThe attacker may compress or encrypt the exported registry hive to evade detection.\u003c/li\u003e\n\u003cli\u003eThe attacker retrieves the exported registry hive for offline analysis.\u003c/li\u003e\n\u003cli\u003eThe attacker extracts credential information from the registry hive, such as password hashes and LSA secrets, to use in lateral movement or privilege escalation.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to acquire sensitive credentials stored within the registry. This can lead to lateral movement within the network, privilege escalation, and ultimately, data exfiltration or system compromise. Compromised credentials can be used to access critical systems and data, causing significant damage to the organization. The impact is considered high due to the potential for widespread access and control over the compromised environment.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable process creation auditing with command line arguments to capture the execution of \u003ccode\u003ereg.exe\u003c/code\u003e with relevant arguments. (\u003ca href=\"https://ela.st/audit-process-creation\"\u003eData Source: Windows Security Event Logs, Sysmon\u003c/a\u003e)\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Registry Hive Export via Reg.exe\u003c/code\u003e to your SIEM to detect the execution of \u003ccode\u003ereg.exe\u003c/code\u003e with arguments indicative of registry hive dumping.\u003c/li\u003e\n\u003cli\u003eImplement access controls and monitor file system activity to detect unauthorized access or modification of registry hive files.\u003c/li\u003e\n\u003cli\u003eReview and restrict the use of \u003ccode\u003ereg.exe\u003c/code\u003e to authorized personnel and processes.\u003c/li\u003e\n\u003cli\u003eMonitor for parent processes of \u003ccode\u003ereg.exe\u003c/code\u003e that are unusual or unexpected, which might indicate malicious activity.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by reviewing the process command line, parent process, and destination of the exported registry hive.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-24T12:00:00Z","date_published":"2024-01-24T12:00:00Z","id":"/briefs/2024-01-24-registry-hive-dump/","summary":"Detects attempts to export sensitive Windows registry hives (SAM/SECURITY) using reg.exe, potentially leading to credential compromise.","title":"Credential Acquisition via Registry Hive Dumping","url":"https://feed.craftedsignal.io/briefs/2024-01-24-registry-hive-dump/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel","CrowdStrike FDR","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows-sandbox","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers may abuse the Windows Sandbox feature to evade detection by running malicious code within the isolated environment. This involves configuring the sandbox with sensitive options such as granting write access to the host file system, enabling network connections, and setting up automatic command execution via logon. By running within the sandbox with these configurations, malware can potentially interact with the host system, while making detection more difficult. This technique is used for defense evasion, hiding artifacts, and executing malicious activities within a virtualized environment to avoid direct exposure on the host. The rule identifies the start of a new container with sensitive configurations like write access to the host file system, network connection and automatic execution via logon command.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system through an exploit or social engineering.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages Windows Sandbox by executing \u003ccode\u003ewsb.exe\u003c/code\u003e or \u003ccode\u003eWindowsSandboxClient.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker configures the sandbox to enable networking using \u003ccode\u003e\u0026lt;Networking\u0026gt;Enable\u0026lt;/Networking\u0026gt;\u003c/code\u003e or \u003ccode\u003e\u0026lt;NetworkingEnabled\u0026gt;true\u0026lt;/NetworkingEnabled\u0026gt;\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker grants the sandbox write access to the host file system using \u003ccode\u003e\u0026lt;HostFolder\u0026gt;C:\\\\\u0026lt;ReadOnly\u0026gt;false\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker sets up a logon command to automatically execute malicious code when the sandbox starts using \u003ccode\u003e\u0026lt;LogonCommand\u0026gt;\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe sandbox initializes and executes the configured logon command.\u003c/li\u003e\n\u003cli\u003eThe malicious code interacts with the host file system and network, performing actions such as data exfiltration or lateral movement.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as deploying ransomware or stealing sensitive information, while operating from within the isolated sandbox environment.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack using Windows Sandbox abuse can lead to a range of negative impacts. Attackers may gain unauthorized access to sensitive data, compromise system integrity, or disrupt business operations. The use of the sandbox environment helps to conceal malicious activity, making detection and remediation more challenging. The damage can include data breaches, financial losses, reputational damage, and regulatory penalties. Successful exploitation allows malware to interact with the host system, potentially affecting multiple systems on the network.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Windows Sandbox with Sensitive Configuration\u0026rdquo; detection rule to your SIEM to identify potential sandbox abuse attempts.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003ewsb.exe\u003c/code\u003e and \u003ccode\u003eWindowsSandboxClient.exe\u003c/code\u003e with command-line arguments that enable networking (\u003ccode\u003e\u0026lt;Networking\u0026gt;Enable\u0026lt;/Networking\u0026gt;\u003c/code\u003e, \u003ccode\u003e\u0026lt;NetworkingEnabled\u0026gt;true\u0026lt;/NetworkingEnabled\u0026gt;\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003ewsb.exe\u003c/code\u003e and \u003ccode\u003eWindowsSandboxClient.exe\u003c/code\u003e with command-line arguments that enable write access to the host file system (\u003ccode\u003e\u0026lt;HostFolder\u0026gt;C:\\\\\u0026lt;ReadOnly\u0026gt;false\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003ewsb.exe\u003c/code\u003e and \u003ccode\u003eWindowsSandboxClient.exe\u003c/code\u003e with command-line arguments that define logon commands (\u003ccode\u003e\u0026lt;LogonCommand\u0026gt;\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture the necessary command-line arguments.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-10T12:00:00Z","date_published":"2024-01-10T12:00:00Z","id":"/briefs/2024-01-windows-sandbox-abuse/","summary":"This rule detects the abuse of Windows Sandbox with sensitive configurations to evade detection, where malware may abuse the sandbox feature to gain write access to the host file system, enable network connections, and automatically execute commands via logon, identifying the start of a new container with these sensitive configurations.","title":"Windows Sandbox Abuse with Sensitive Configuration","url":"https://feed.craftedsignal.io/briefs/2024-01-windows-sandbox-abuse/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Build Engine","Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","execution","msbuild","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThe Microsoft Build Engine (MSBuild) is a software build platform commonly used by Windows developers. When MSBuild is started by an Office application like Word or Excel, it deviates from typical usage patterns. This behavior can be indicative of a malicious document executing a script payload as part of a defense evasion tactic. Attackers may leverage MSBuild to execute code or perform actions that would otherwise be blocked or detected. This activity is particularly concerning because it can bypass traditional security measures that focus on blocking suspicious executables or scripts directly launched by Office applications. The rule was created in March 2020, and last updated in April 2026.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eA user opens a malicious Office document (e.g., Word, Excel, PowerPoint).\u003c/li\u003e\n\u003cli\u003eThe Office document contains an embedded macro or exploit that triggers the execution of MSBuild.exe.\u003c/li\u003e\n\u003cli\u003eMSBuild.exe is launched as a child process of the Office application (e.g., winword.exe, excel.exe, powerpnt.exe).\u003c/li\u003e\n\u003cli\u003eMSBuild executes a project file or inline task specified in the command line. This can involve compiling code, executing scripts, or performing other actions.\u003c/li\u003e\n\u003cli\u003eThe executed code or script performs malicious activities, such as downloading additional payloads, modifying system settings, or establishing persistence.\u003c/li\u003e\n\u003cli\u003eMSBuild may spawn child processes, such as cmd.exe, powershell.exe, or other utilities, to further execute malicious commands.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, which could include data exfiltration, installing malware, or gaining unauthorized access to the system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to the execution of arbitrary code on the victim\u0026rsquo;s machine, potentially resulting in data theft, malware installation, or complete system compromise. Since MSBuild is a legitimate Microsoft tool, its use by malicious actors can make detection more challenging. The impact is high because it leverages a trusted process to carry out malicious activities, evading standard security measures.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Microsoft Build Engine Started by an Office Application\u0026rdquo; to your SIEM to detect this specific behavior based on process creation events.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging with the appropriate configuration to capture the necessary process start events for the Sigma rule to function correctly.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the command-line arguments of MSBuild.exe and the parent process information, including the executable name and command line.\u003c/li\u003e\n\u003cli\u003eMonitor process execution events for MSBuild.exe with parent processes being Office applications as a high priority indicator of potential compromise.\u003c/li\u003e\n\u003cli\u003eReview and harden Office macro settings to prevent execution of malicious macros.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-09T18:22:00Z","date_published":"2024-01-09T18:22:00Z","id":"/briefs/2024-01-msbuild-office-app/","summary":"The Microsoft Build Engine (MSBuild) being started by an Office application is unusual behavior and could indicate a malicious document executing a script payload for defense evasion.","title":"Microsoft Build Engine Started by an Office Application","url":"https://feed.craftedsignal.io/briefs/2024-01-msbuild-office-app/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["high"],"_cs_tags":["ntlm-relay","credential-access","windows","webdav"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies attempts to coerce local NTLM authentication over HTTP through WebDAV named-pipe paths, focusing on Print Spooler and SRVSVC. Attackers can exploit this vulnerability, often combined with tools like NTLMRelay2Self, PetitPotam, or modified versions of krbrelayx\u0026rsquo;s printerbug.py, to relay the obtained credentials and escalate their privileges within the network. This technique allows attackers to bypass traditional security measures by leveraging legitimate Windows protocols for malicious purposes. Successful exploitation can lead to domain dominance and unauthorized access to sensitive resources. This activity is often associated with post-exploitation activity following initial access via other means.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003erundll32.exe\u003c/code\u003e to load \u003ccode\u003edavclnt.dll\u003c/code\u003e using the \u003ccode\u003eDavSetCookie\u003c/code\u003e function.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003erundll32.exe\u003c/code\u003e process is invoked with arguments specifying a named pipe path over HTTP, such as \u003ccode\u003ehttp*/print/pipe/*\u003c/code\u003e, \u003ccode\u003ehttp*/pipe/spoolss\u003c/code\u003e, or \u003ccode\u003ehttp*/pipe/srvsvc\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe system attempts to authenticate to the specified HTTP endpoint using NTLM.\u003c/li\u003e\n\u003cli\u003eThe attacker intercepts the NTLM authentication request.\u003c/li\u003e\n\u003cli\u003eUsing a relay tool like NTLMRelay2Self or ntlmrelayx, the attacker relays the captured NTLM credentials to another service or machine.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the relayed credentials to escalate privileges or gain unauthorized access to network resources.\u003c/li\u003e\n\u003cli\u003eThe attacker may then perform lateral movement, data exfiltration, or other malicious activities.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to escalate privileges within the compromised system and potentially the entire domain. This can lead to unauthorized access to sensitive data, deployment of ransomware, or other destructive activities. The impact ranges from data breaches and financial losses to complete system compromise. Depending on the targeted accounts, the attacker may be able to achieve domain administrator privileges.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Potential Local NTLM Relay via HTTP\u0026rdquo; to your SIEM to detect the execution of \u003ccode\u003erundll32.exe\u003c/code\u003e with specific arguments indicative of NTLM relay attempts.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to ensure the necessary data is available for the Sigma rule to function correctly.\u003c/li\u003e\n\u003cli\u003eMonitor network connections originating from processes that load \u003ccode\u003edavclnt.dll\u003c/code\u003e to identify potential NTLM relay traffic.\u003c/li\u003e\n\u003cli\u003eInvestigate and block the usage of tools like NTLMRelay2Self, PetitPotam, and ntlmrelayx within the environment.\u003c/li\u003e\n\u003cli\u003eImplement mitigations for NTLM relay attacks, such as enabling Extended Protection for Authentication (EPA) and disabling NTLM where possible.\u003c/li\u003e\n\u003cli\u003eReview and restrict the usage of WebClient service and Print Spooler service where not required.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-09T14:00:00Z","date_published":"2024-01-09T14:00:00Z","id":"/briefs/2024-01-ntlm-relay-http/","summary":"Adversaries may coerce local NTLM authentication over HTTP via WebDAV named-pipe paths (Print Spooler, SRVSVC), then relay credentials to elevate privileges.","title":"Potential Local NTLM Relay via HTTP","url":"https://feed.craftedsignal.io/briefs/2024-01-ntlm-relay-http/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Defend","CCleaner","ManageEngine UEMS Agent","ManageEngine DesktopCentral Agent"],"_cs_severities":["medium"],"_cs_tags":["persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","ManageEngine","CCleaner","Elastic","SentinelOne"],"content_html":"\u003cp\u003eAdversaries may abuse scheduled tasks to maintain persistence on a compromised system. This involves creating or modifying scheduled tasks to execute malicious code at specific times or intervals. This activity can be used to ensure that the attacker\u0026rsquo;s code remains active even after a system restart or user logout. The detection rule identifies suspicious job creation by monitoring specific file paths and extensions, excluding known legitimate processes to flag potential abuse. The rule is designed for data generated by Elastic Defend, but also supports Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to establish persistence.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a script or program to create a new scheduled job within the \u003ccode\u003eC:\\Windows\\Tasks\\\u003c/code\u003e directory.\u003c/li\u003e\n\u003cli\u003eThe scheduled job is configured to execute a malicious payload at a specified time or interval.\u003c/li\u003e\n\u003cli\u003eThe malicious payload could be a script (e.g., PowerShell) or an executable.\u003c/li\u003e\n\u003cli\u003eThe scheduled job executes, triggering the malicious payload.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistent access to the system.\u003c/li\u003e\n\u003cli\u003eThe attacker performs malicious activities, such as data exfiltration or lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to maintain a persistent presence on the compromised system. This allows them to execute malicious code, steal sensitive information, or perform other malicious activities over an extended period. The number of affected systems can vary depending on the scope of the initial compromise and the attacker\u0026rsquo;s objectives.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) logging to monitor file creation events on Windows systems.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Suspicious Scheduled Job Creation\u0026rdquo; to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on scheduled jobs created in the \u003ccode\u003eC:\\Windows\\Tasks\\\u003c/code\u003e directory with a \u0026ldquo;.job\u0026rdquo; extension.\u003c/li\u003e\n\u003cli\u003eReview and update exclusion lists for known legitimate scheduled job creation processes (e.g., CCleaner, ManageEngine) to minimize false positives.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-09T12:00:00Z","date_published":"2024-01-09T12:00:00Z","id":"/briefs/2024-01-09-scheduled-job-persistence/","summary":"This detection rule identifies attempts to establish persistence on Windows systems by creating scheduled jobs in the Windows Tasks directory, excluding known legitimate jobs.","title":"Persistence via Scheduled Job Creation","url":"https://feed.craftedsignal.io/briefs/2024-01-09-scheduled-job-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["credential-access","lsass","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eThis rule identifies attempts to access the LSASS process via Windows API calls, specifically \u003ccode\u003eOpenProcess\u003c/code\u003e, \u003ccode\u003eOpenThread\u003c/code\u003e, and \u003ccode\u003eReadProcessMemory\u003c/code\u003e. The Local Security Authority Subsystem Service (LSASS) is a critical Windows component responsible for managing user authentication and security policies. Attackers often target LSASS to dump credentials from memory for lateral movement and privilege escalation. This detection focuses on identifying unusual processes attempting to access the LSASS process, excluding common legitimate applications and directories. The rule leverages data from Elastic Defend and Microsoft Defender XDR to identify suspicious activity and provide defenders with actionable alerts.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the target system through various means.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to escalate privileges to gain administrative rights.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a custom tool or script to call the \u003ccode\u003eOpenProcess\u003c/code\u003e, \u003ccode\u003eOpenThread\u003c/code\u003e or \u003ccode\u003eReadProcessMemory\u003c/code\u003e Windows APIs.\u003c/li\u003e\n\u003cli\u003eThe tool targets the \u003ccode\u003elsass.exe\u003c/code\u003e process to obtain a handle for memory access.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the obtained handle to read LSASS memory, searching for credential data.\u003c/li\u003e\n\u003cli\u003eThe attacker extracts usernames, passwords, and other sensitive information from the dumped memory.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the stolen credentials for lateral movement to other systems on the network.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, which may include data exfiltration or system compromise.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to the compromise of domain credentials, allowing attackers to move laterally within the network and gain access to sensitive resources. This can result in data breaches, system compromise, and significant financial or reputational damage. The rule aims to detect these attacks early, limiting the scope of the potential compromise.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;LSASS API Access by Non-Standard Process\u0026rdquo; to your SIEM and tune for your environment to detect suspicious access to the LSASS process.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by this rule, focusing on the process execution chain and the access rights requested as documented in the provided Microsoft documentation.\u003c/li\u003e\n\u003cli\u003eEnable process creation and API call logging via Elastic Defend or Microsoft Defender XDR to provide the necessary data for this detection.\u003c/li\u003e\n\u003cli\u003eReview and harden LSASS protection mechanisms such as Credential Guard to minimize the risk of successful credential dumping.\u003c/li\u003e\n\u003cli\u003eImplement the Osquery queries to gather system information like DNS cache, services, and unsigned executables, to aid in investigation and threat hunting.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-09T12:00:00Z","date_published":"2024-01-09T12:00:00Z","id":"/briefs/2024-01-lsass-process-access/","summary":"Detection of access attempts to the LSASS handle, indicating potential credential dumping by monitoring API calls (OpenProcess, OpenThread, ReadProcessMemory) targeting lsass.exe.","title":"LSASS Process Access via Windows API","url":"https://feed.craftedsignal.io/briefs/2024-01-lsass-process-access/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","persistence","privilege-escalation","masquerading"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies suspicious child processes spawned by WerFault.exe, the Windows Error Reporting tool. Attackers can abuse WerFault by manipulating the \u003ccode\u003eSilentProcessExit\u003c/code\u003e registry key to execute malicious processes. This technique allows for defense evasion, persistence, and privilege escalation. The detection focuses on WerFault processes with specific command-line arguments (\u003ccode\u003e-s\u003c/code\u003e, \u003ccode\u003e-t\u003c/code\u003e, and \u003ccode\u003e-c\u003c/code\u003e) known to be used in SilentProcessExit exploitation, while excluding legitimate executables like \u003ccode\u003eInitcrypt.exe\u003c/code\u003e and \u003ccode\u003eHeimdal.Guard.exe\u003c/code\u003e. The rule helps defenders identify potential attempts to hijack the error reporting mechanism for malicious purposes. The monitored data sources include Windows Event Logs, Sysmon, Elastic Defend, Microsoft Defender XDR, and SentinelOne.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the \u003ccode\u003eSilentProcessExit\u003c/code\u003e registry key to specify a malicious process to be executed when a target application crashes. This involves setting the \u003ccode\u003eReportingMode\u003c/code\u003e and \u003ccode\u003eDebugger\u003c/code\u003e values under the \u003ccode\u003eSilentProcessExit\u003c/code\u003e key for the target application.\u003c/li\u003e\n\u003cli\u003eThe attacker triggers a crash in the target application or waits for a legitimate crash to occur.\u003c/li\u003e\n\u003cli\u003eWerFault.exe is invoked to handle the application crash.\u003c/li\u003e\n\u003cli\u003eDue to the registry modification, WerFault.exe spawns the attacker-controlled process, passing command-line arguments such as \u003ccode\u003e-s\u003c/code\u003e, \u003ccode\u003e-t\u003c/code\u003e, and \u003ccode\u003e-c\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker-controlled process executes with the privileges of WerFault.exe, potentially achieving privilege escalation.\u003c/li\u003e\n\u003cli\u003eThe malicious process performs actions such as injecting code into other processes, establishing persistence, or exfiltrating data.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objectives, such as maintaining persistence, escalating privileges, or evading detection.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to persistence, privilege escalation, and defense evasion. Attackers can use this technique to execute malicious code with elevated privileges, potentially bypassing security controls and gaining unauthorized access to sensitive data and system resources. The number of victims and affected sectors can vary depending on the attacker\u0026rsquo;s objectives and the scope of the initial compromise.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture WerFault.exe child processes (Data Source: Sysmon).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;WerFault Child Process Masquerading\u0026rdquo; to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eReview the \u003ccode\u003eSilentProcessExit\u003c/code\u003e registry key for unauthorized modifications (registry_set event).\u003c/li\u003e\n\u003cli\u003eInvestigate any WerFault.exe processes with command-line arguments \u003ccode\u003e-s\u003c/code\u003e, \u003ccode\u003e-t\u003c/code\u003e, and \u003ccode\u003e-c\u003c/code\u003e (process_creation event).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-09T10:00:00Z","date_published":"2024-01-09T10:00:00Z","id":"/briefs/2024-01-09-werfault-child-process/","summary":"This rule detects suspicious child processes of WerFault.exe, a Windows error reporting tool, indicating potential abuse of the SilentProcessExit registry key to execute malicious processes stealthily for defense evasion, persistence, and privilege escalation.","title":"Suspicious WerFault Child Process Abuse","url":"https://feed.craftedsignal.io/briefs/2024-01-09-werfault-child-process/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows","Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Endgame","Kaspersky Security for Windows Server","Desktop Central Agent","SAP NW Setup"],"_cs_severities":["medium"],"_cs_tags":["persistence","app-compat","shim","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","SAP","Kaspersky","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers can exploit the Windows Application Compatibility Shim functionality to maintain persistence and execute arbitrary code within legitimate Windows processes. This is achieved by installing custom shim databases, which are designed to ensure older applications run smoothly on newer operating systems. By manipulating these databases, attackers can stealthily inject malicious code into trusted processes. The rule detects changes in specific registry paths associated with the installation of these databases, excluding known legitimate processes to minimize false positives. This technique allows for the execution of malicious code without directly modifying the target application\u0026rsquo;s executable, making it difficult to detect with traditional methods.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the registry to create a new entry for a custom shim database. The registry path targeted is typically under \u003ccode\u003eHKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\AppCompatFlags\\Custom\\\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker writes a malicious \u003ccode\u003e.sdb\u003c/code\u003e file containing the custom shim database to a location on disk.\u003c/li\u003e\n\u003cli\u003eThe registry entry created points to the malicious \u003ccode\u003e.sdb\u003c/code\u003e file.\u003c/li\u003e\n\u003cli\u003eWhen a targeted application is launched, Windows checks the AppCompatFlags registry keys.\u003c/li\u003e\n\u003cli\u003eThe system loads the malicious shim database specified in the registry.\u003c/li\u003e\n\u003cli\u003eThe malicious code within the shim database is executed in the context of the targeted application.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves persistence, as the malicious shim database is loaded every time the targeted application is run.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to maintain persistent access to the system, even after reboots or software updates. The injected code runs within the context of a legitimate process, which can evade detection by traditional security tools. This can lead to data theft, system compromise, or further malicious activities, such as lateral movement within the network. The use of application shimming for persistence affects systems running Windows and can impact organizations of any size or sector.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Custom Shim Database Installation\u003c/code\u003e to your SIEM to identify suspicious registry modifications related to application shimming.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to ensure the necessary data is available for the Sigma rule to function.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on processes that are not in the exclusion list.\u003c/li\u003e\n\u003cli\u003eBlock or quarantine any identified malicious \u003ccode\u003e.sdb\u003c/code\u003e files to prevent further execution.\u003c/li\u003e\n\u003cli\u003eReview and update the exclusion list in the Sigma rule with any newly identified legitimate applications that use shim databases, reducing false positives.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-09T10:00:00Z","date_published":"2024-01-09T10:00:00Z","id":"/briefs/2024-01-09-app-compat-shim-persistence/","summary":"Attackers abuse the Application Compatibility Shim functionality in Windows to establish persistence and achieve arbitrary code execution by installing malicious shim databases, which this detection identifies through monitoring registry changes.","title":"Detection of Custom Shim Database Installation for Persistence","url":"https://feed.craftedsignal.io/briefs/2024-01-09-app-compat-shim-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows","eventlog"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers often disable Windows Event and Security Logs to evade detection on compromised systems. This activity involves tampering with, clearing, and deleting event log data to break SIEM detections, cover their tracks, and slow down incident response. The methods employed include using the \u003ccode\u003elogman\u003c/code\u003e utility, PowerShell commands to disable the EventLog service, or \u003ccode\u003eauditpol\u003c/code\u003e to disable auditing. These actions are typically performed after initial access and privilege escalation to hinder forensic investigations and maintain persistence within the environment. Defenders should monitor for these specific tools and command-line arguments to identify potential attempts to disable logging.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system, possibly through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to administrator level to gain the necessary permissions to modify event logging settings.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003elogman.exe\u003c/code\u003e with arguments to stop or delete EventLog traces (e.g., \u003ccode\u003elogman.exe stop EventLog-*\u003c/code\u003e, \u003ccode\u003elogman.exe delete EventLog-*\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eAlternatively, the attacker uses PowerShell with \u003ccode\u003eSet-Service\u003c/code\u003e cmdlet to disable the EventLog service (e.g., \u003ccode\u003epowershell.exe Set-Service EventLog -StartupType Disabled\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe attacker can also use \u003ccode\u003eauditpol.exe\u003c/code\u003e to disable auditing policies, preventing future events from being logged (e.g., \u003ccode\u003eauditpol.exe /success:disable\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eAfter disabling logging, the attacker performs malicious activities such as lateral movement, data exfiltration, or malware deployment, with a reduced risk of detection.\u003c/li\u003e\n\u003cli\u003eThe attacker removes traces of their activity from other logs if possible.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence and continues to exploit the compromised environment.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful disabling of Windows Event and Security Logs can severely hinder incident response and forensic investigations. The absence of log data makes it difficult to detect ongoing malicious activity, understand the scope of the compromise, and attribute the attack. This can lead to prolonged dwell time for attackers, increased data exfiltration, and greater overall damage to the organization.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Disable Windows Event and Security Logs Using Built-in Tools\u0026rdquo; to your SIEM to detect the execution of \u003ccode\u003elogman.exe\u003c/code\u003e, PowerShell, and \u003ccode\u003eauditpol.exe\u003c/code\u003e with specific arguments related to disabling event logs.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003elogman.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e, \u003ccode\u003epwsh.exe\u003c/code\u003e, \u003ccode\u003epowershell_ise.exe\u003c/code\u003e, and \u003ccode\u003eauditpol.exe\u003c/code\u003e with command-line arguments that indicate an attempt to disable event logging.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture detailed command-line arguments for process monitoring.\u003c/li\u003e\n\u003cli\u003eRegularly review and audit Group Policy settings related to event logging to prevent unauthorized modifications.\u003c/li\u003e\n\u003cli\u003eMonitor for changes to the EventLog service configuration, including startup type and status, using system monitoring tools.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-04T10:00:00Z","date_published":"2024-01-04T10:00:00Z","id":"/briefs/2024-01-disable-windows-logs/","summary":"Attackers attempt to disable Windows Event and Security Logs using logman, PowerShell, or auditpol to evade detection and cover their tracks.","title":"Disable Windows Event and Security Logs Using Built-in Tools","url":"https://feed.craftedsignal.io/briefs/2024-01-disable-windows-logs/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft HTML Help system","Elastic Defend","Microsoft Defender XDR","Sysmon","SentinelOne Cloud Funnel","CrowdStrike"],"_cs_severities":["medium"],"_cs_tags":["execution","defense-evasion","compiled-html","windows","proxy-execution"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eAttackers are known to deliver malicious payloads within compiled HTML files (.chm) to bypass security measures and gain initial access to systems. This technique leverages the Microsoft HTML Help system and its associated executable, hh.exe, to proxy the execution of malicious code. Compiled HTML files can contain various types of content, including HTML documents, images, and scripting languages like VBA, JScript, Java, and ActiveX. By embedding malicious scripts or executables within a .chm file, attackers can trick users into executing them when they open the file. This is particularly effective because hh.exe is a signed binary, which may allow it to bypass certain security controls. The scope of this technique affects Windows systems where the HTML Help system is installed.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker crafts a malicious .chm file containing embedded malicious code, such as a PowerShell script or executable.\u003c/li\u003e\n\u003cli\u003eThe attacker delivers the .chm file to the victim via social engineering, such as phishing or malicious websites.\u003c/li\u003e\n\u003cli\u003eThe victim opens the .chm file, causing hh.exe to launch.\u003c/li\u003e\n\u003cli\u003ehh.exe processes the .chm file, rendering its content, which includes the embedded malicious script or executable.\u003c/li\u003e\n\u003cli\u003eThe malicious code executes, often spawning a scripting interpreter like \u003ccode\u003epowershell.exe\u003c/code\u003e or \u003ccode\u003ecmd.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe scripting interpreter executes commands to download additional payloads or perform malicious actions on the system.\u003c/li\u003e\n\u003cli\u003eThe attacker gains initial access to the victim\u0026rsquo;s system.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges and moves laterally within the network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to initial access, code execution, and potentially full system compromise. This can result in data theft, malware installation, and further lateral movement within the network. The severity and impact depend on the permissions of the user running hh.exe and the nature of the malicious payload.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Compiled HTML File Spawning Suspicious Processes\u0026rdquo; to your SIEM to detect instances where \u003ccode\u003ehh.exe\u003c/code\u003e is the parent process of scripting interpreters.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to provide the necessary data for the Sigma rule to function correctly.\u003c/li\u003e\n\u003cli\u003eMonitor process execution chains for unknown processes originating from \u003ccode\u003ehh.exe\u003c/code\u003e, as mentioned in the investigation guide.\u003c/li\u003e\n\u003cli\u003eImplement email filtering and security awareness training to prevent users from opening malicious .chm files delivered via phishing.\u003c/li\u003e\n\u003cli\u003eBlock the execution of unsigned or untrusted executables in the environment to reduce the risk of malicious code execution.\u003c/li\u003e\n\u003cli\u003eUse endpoint detection and response (EDR) solutions like Elastic Defend, CrowdStrike, Microsoft Defender XDR, and SentinelOne to detect and respond to malicious activity.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T18:30:00Z","date_published":"2024-01-03T18:30:00Z","id":"/briefs/2024-01-compiled-html-execution/","summary":"Adversaries may conceal malicious code in compiled HTML files (.chm) and deliver them to a victim for execution, using the HTML Help executable (hh.exe) to proxy the execution of scripting interpreters and bypass security controls.","title":"Process Activity via Compiled HTML File Execution","url":"https://feed.craftedsignal.io/briefs/2024-01-compiled-html-execution/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["credential-access","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","CrowdStrike","SentinelOne"],"content_html":"\u003cp\u003eThis rule identifies the creation of symbolic links to shadow copies on Windows systems. Attackers use this technique to gain access to sensitive files stored within shadow copies, including the ntds.dit file (containing password hashes), system boot keys, and browser offline credentials. This approach allows them to bypass normal file access controls and extract credentials for lateral movement or privilege escalation. The detection rule is designed to ingest data from various sources, including Elastic Defend, CrowdStrike, Microsoft Defender XDR, SentinelOne Cloud Funnel, Sysmon, and Windows Security Event Logs, providing broad coverage across different endpoint security solutions. The activity is typically initiated by command-line tools like cmd.exe or powershell.exe, making detection through process monitoring feasible. This technique is particularly relevant as it targets credential dumping, a critical stage in many attack campaigns.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system, possibly through phishing or exploitation of a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker elevates privileges to gain administrative rights, which are required to create shadow copies and symbolic links.\u003c/li\u003e\n\u003cli\u003eThe attacker creates a volume shadow copy using \u003ccode\u003evssadmin.exe\u003c/code\u003e or similar tools.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003emklink\u003c/code\u003e command or PowerShell \u003ccode\u003eNew-Item -ItemType SymbolicLink\u003c/code\u003e to create a symbolic link to the shadow copy path.\u003c/li\u003e\n\u003cli\u003eThe symbolic link points to a directory within the shadow copy containing sensitive files like \u003ccode\u003entds.dit\u003c/code\u003e or browser credential stores.\u003c/li\u003e\n\u003cli\u003eThe attacker copies the targeted sensitive files (e.g., \u003ccode\u003entds.dit\u003c/code\u003e) from the shadow copy using the symbolic link.\u003c/li\u003e\n\u003cli\u003eThe attacker removes the shadow copy to cover their tracks, although the symbolic link creation remains as evidence.\u003c/li\u003e\n\u003cli\u003eThe attacker extracts credentials from the copied \u003ccode\u003entds.dit\u003c/code\u003e file offline for use in lateral movement or further attacks.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to gain unauthorized access to sensitive credentials stored on the compromised system. This can lead to lateral movement within the network, privilege escalation, and ultimately, the compromise of critical assets. If the \u003ccode\u003entds.dit\u003c/code\u003e file is accessed, the entire Active Directory domain could be at risk, potentially affecting thousands of users and systems. This type of attack is particularly damaging as it allows attackers to operate undetected for extended periods while they harvest credentials.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rule \u0026ldquo;Symbolic Link to Shadow Copy Created via Cmd\u0026rdquo; to detect the creation of symbolic links to shadow copies via \u003ccode\u003ecmd.exe\u003c/code\u003e (rules).\u003c/li\u003e\n\u003cli\u003eDeploy the provided Sigma rule \u0026ldquo;Symbolic Link to Shadow Copy Created via PowerShell\u0026rdquo; to detect the creation of symbolic links to shadow copies via \u003ccode\u003epowershell.exe\u003c/code\u003e (rules).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 1 (Process Creation) logging to provide necessary data for the Sigma rules to function correctly (setup).\u003c/li\u003e\n\u003cli\u003eReview the \u0026ldquo;Investigating Symbolic Link to Shadow Copy Created\u0026rdquo; section in the rule\u0026rsquo;s notes for triage and analysis steps when the rule triggers.\u003c/li\u003e\n\u003cli\u003eMonitor for the usage of \u003ccode\u003emklink\u003c/code\u003e command with the \u003ccode\u003eHarddiskVolumeShadowCopy\u003c/code\u003e argument in process command lines.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T18:15:00Z","date_published":"2024-01-03T18:15:00Z","id":"/briefs/2024-01-shadow-copy-symlink/","summary":"Adversaries may create symbolic links to shadow copies to access sensitive files such as ntds.dit and browser credentials, enabling credential dumping using cmd.exe or powershell.exe.","title":"Symbolic Link Creation to Shadow Copies for Credential Access","url":"https://feed.craftedsignal.io/briefs/2024-01-shadow-copy-symlink/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Edge","Chrome","Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["high"],"_cs_tags":["credential-access","windows","browser-exploitation"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Google","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies instances where a browser process, specifically Google Chrome or Microsoft Edge, is initiated from an unexpected parent process on a Windows system. The rule focuses on scenarios where browsers are launched with arguments indicative of remote debugging, headless automation, or minimal user interaction. Such activity can signal an attempt to manipulate a browser session for malicious purposes, potentially leading to credential theft or unauthorized access to sensitive information. The rule is designed to leverage data from Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, Sysmon, and Windows Process Creation Logs.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes a script or command to launch a browser process (chrome.exe or msedge.exe).\u003c/li\u003e\n\u003cli\u003eThe browser is launched with specific command-line arguments, such as \u003ccode\u003e--remote-debugging-port\u003c/code\u003e, \u003ccode\u003e--headless\u003c/code\u003e, or \u003ccode\u003e--window-position=-x,-y\u003c/code\u003e, to enable remote control or hide the browser window.\u003c/li\u003e\n\u003cli\u003eThe parent process of the browser is an unusual executable, not typically associated with launching browsers (e.g., not explorer.exe).\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the remote debugging port to interact with the browser session programmatically.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to steal credentials or session cookies from the browser.\u003c/li\u003e\n\u003cli\u003eThe attacker uses stolen credentials to access sensitive data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to the theft of user credentials, enabling unauthorized access to sensitive data and systems. This could result in financial loss, data breaches, and reputational damage for affected organizations. The targeted use of browser manipulation techniques increases the likelihood of bypassing traditional security controls.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eBrowser Process Spawned from Unusual Parent\u003c/code\u003e to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process-creation logging (Event ID 1) to collect the necessary data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the \u003ccode\u003eBrowser Process Spawned from Unusual Parent\u003c/code\u003e Sigma rule.\u003c/li\u003e\n\u003cli\u003eReview process command lines for arguments like \u003ccode\u003e--remote-debugging-port\u003c/code\u003e or \u003ccode\u003e--headless\u003c/code\u003e to identify potential browser manipulation attempts.\u003c/li\u003e\n\u003cli\u003eMonitor network connections originating from browser processes for unexpected destinations, as described in the investigation guide from the source.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T18:15:00Z","date_published":"2024-01-03T18:15:00Z","id":"/briefs/2024-01-browser-unusual-parent/","summary":"Attackers may attempt credential theft by launching browsers (Chrome, Edge) with remote debugging, headless automation, or minimal arguments from an unusual parent process on Windows systems.","title":"Browser Process Spawned from an Unusual Parent","url":"https://feed.craftedsignal.io/briefs/2024-01-browser-unusual-parent/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","CrowdStrike"],"_cs_severities":["high"],"_cs_tags":["credential-access","mimikatz","memssp","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies the creation of the \u003ccode\u003emimilsa.log\u003c/code\u003e file, a default log generated by the Mimikatz \u003ccode\u003emisc::memssp\u003c/code\u003e module. The \u003ccode\u003emisc::memssp\u003c/code\u003e module injects a malicious Security Support Provider (SSP) into the Local Security Authority Subsystem Service (LSASS) process. This injected SSP logs credentials from subsequent logons to the compromised host, allowing attackers to capture sensitive information. The creation of this log file is a strong indicator of credential access attempts and the potential compromise of user accounts and system security. This rule is designed for data generated by Elastic Defend and also supports data from CrowdStrike, Microsoft Defender XDR, and SentinelOne Cloud Funnel.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes Mimikatz or a similar tool with the \u003ccode\u003emisc::memssp\u003c/code\u003e module.\u003c/li\u003e\n\u003cli\u003eMimikatz injects a malicious SSP library (e.g., \u003ccode\u003emimilib.dll\u003c/code\u003e) into the LSASS process (\u003ccode\u003elsass.exe\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe injected SSP hooks into the authentication process.\u003c/li\u003e\n\u003cli\u003eWhen users log on to the system, the SSP captures their credentials.\u003c/li\u003e\n\u003cli\u003eThe captured credentials are written to the \u003ccode\u003emimilsa.log\u003c/code\u003e file, typically located in \u003ccode\u003eC:\\Windows\\System32\\\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker retrieves the \u003ccode\u003emimilsa.log\u003c/code\u003e file to obtain the captured credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the stolen credentials to escalate privileges, move laterally within the network, and access sensitive resources.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful Mimikatz MemSSP attack can lead to the compromise of user accounts, including those with administrative privileges. This allows attackers to gain unauthorized access to sensitive data, systems, and resources within the organization. Lateral movement becomes easier, potentially impacting a large number of systems. The compromised credentials can also be used for external attacks, such as gaining access to cloud services or other external resources.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eMimikatz Memssp Log File Detected\u003c/code\u003e to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon file creation logging to detect the creation of \u003ccode\u003emimilsa.log\u003c/code\u003e files.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the process that created the log file and any subsequent file access.\u003c/li\u003e\n\u003cli\u003eMonitor for the presence of \u003ccode\u003emimilib.dll\u003c/code\u003e and any LSA Security Packages registry modifications, as these may indicate persistent SSP installation.\u003c/li\u003e\n\u003cli\u003eReview and restrict interactive logons to high-value hosts to minimize the potential for credential theft.\u003c/li\u003e\n\u003cli\u003eInvestigate related alerts for the same \u003ccode\u003ehost.id\u003c/code\u003e in the last 48 hours covering delivery, privilege escalation, LSASS access, persistence, lateral movement, or additional credential access.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T17:00:00Z","date_published":"2024-01-03T17:00:00Z","id":"/briefs/2024-01-mimikatz-memssp-log/","summary":"This rule detects the creation of the default Mimikatz MemSSP credential log file, mimilsa.log, which is created after the misc::memssp module injects a malicious Security Support Provider into LSASS, potentially capturing credentials from subsequent logons.","title":"Mimikatz MemSSP Log File Detection","url":"https://feed.craftedsignal.io/briefs/2024-01-mimikatz-memssp-log/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows Subsystem for Linux","Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","CrowdStrike FDR"],"_cs_severities":["medium"],"_cs_tags":["wsl","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers may leverage the Windows Subsystem for Linux (WSL) to evade detection by operating within a Linux environment on a Windows host. The installation of a new WSL distribution involves specific registry modifications. This rule identifies such modifications, providing an alert when a new WSL distribution is installed. This is important for defenders as it could signal an attacker setting up a persistent and potentially hidden environment for malicious activities. WSL allows attackers to utilize Linux tools and techniques on a Windows system, potentially bypassing traditional Windows-based security measures.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial Access: The attacker gains initial access to the Windows system through existing vulnerabilities or compromised credentials.\u003c/li\u003e\n\u003cli\u003ePrivilege Escalation: The attacker elevates their privileges to perform system-level changes, including registry modifications.\u003c/li\u003e\n\u003cli\u003eWSL Installation: The attacker initiates the installation of a WSL distribution. This may involve downloading and executing a WSL installer package.\u003c/li\u003e\n\u003cli\u003eRegistry Modification: During installation, the system modifies the registry to configure and register the new WSL distribution. Specifically, keys under \u003ccode\u003eHKLM\\\\SOFTWARE\\\\Microsoft\\\\Windows\\\\CurrentVersion\\\\Lxss\\\\\u003c/code\u003e are created/modified.\u003c/li\u003e\n\u003cli\u003eWSL Environment Setup: The attacker configures the installed WSL distribution, potentially installing additional tools and software needed for their objectives.\u003c/li\u003e\n\u003cli\u003eExecution of Malicious Activities: The attacker executes malicious commands and scripts within the WSL environment, leveraging Linux tools to perform actions such as lateral movement, data exfiltration, or persistence.\u003c/li\u003e\n\u003cli\u003eDefense Evasion: The attacker utilizes WSL to evade detection, as traditional Windows-based security tools may not effectively monitor or analyze activity within the Linux subsystem.\u003c/li\u003e\n\u003cli\u003ePersistence: The attacker establishes persistence within the WSL environment, ensuring continued access to the compromised system even after reboots or security updates.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to establish a hidden and persistent environment within the compromised Windows system. This can lead to data theft, system compromise, and further propagation of the attack within the network. The number of victims and affected sectors depends on the scope and objectives of the attacker. The use of WSL for malicious purposes can significantly complicate incident response and remediation efforts.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect WSL Installation via Registry Modification\u0026rdquo; to your SIEM to detect new WSL installations by monitoring registry changes.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to capture the necessary data for the Sigma rule to function correctly (see setup instructions in the rule description).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule to determine the legitimacy of the WSL installation and identify potential malicious activities.\u003c/li\u003e\n\u003cli\u003eMonitor for execution of suspicious processes within WSL environments, as described in \u0026ldquo;Execution via Windows Subsystem for Linux - db7dbad5-08d2-4d25-b9b1-d3a1e4a15efd\u0026rdquo;.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T16:00:00Z","date_published":"2024-01-03T16:00:00Z","id":"/briefs/2024-01-wsl-registry-modification/","summary":"This rule detects registry modifications indicative of a new Windows Subsystem for Linux (WSL) distribution installation, a technique adversaries may leverage to evade detection by utilizing Linux environments within Windows.","title":"Windows Subsystem for Linux Distribution Installed via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-wsl-registry-modification/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["boot-configuration","bcdedit","impact","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne","Elastic"],"content_html":"\u003cp\u003eThis detection rule identifies the execution of \u003ccode\u003ebcdedit.exe\u003c/code\u003e with specific arguments that modify the boot configuration data (BCD) store in Windows systems. Attackers or malware may use this technique to disable Windows Error Recovery (\u003ccode\u003erecoveryenabled\u003c/code\u003e) or to ignore errors during the boot process (\u003ccode\u003ebootstatuspolicy ignoreallfailures\u003c/code\u003e). These modifications are often performed to prevent systems from recovering properly after an attack, particularly in ransomware scenarios. The rule is designed to work with data from Elastic Defend, CrowdStrike, Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon. The detection logic focuses on process execution events that include the relevant \u003ccode\u003ebcdedit.exe\u003c/code\u003e command-line arguments. Defenders should be aware of legitimate uses of \u003ccode\u003ebcdedit.exe\u003c/code\u003e by administrators for troubleshooting or data recovery purposes, so context is crucial.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial Access: The attacker gains initial access to the system through various means, such as phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003ePrivilege Escalation: The attacker escalates privileges to gain administrative access, required to modify boot configuration settings.\u003c/li\u003e\n\u003cli\u003eReconnaissance: The attacker performs reconnaissance to identify the system\u0026rsquo;s configuration and identify appropriate targets for modification.\u003c/li\u003e\n\u003cli\u003eDisable Recovery: The attacker uses \u003ccode\u003ebcdedit.exe\u003c/code\u003e to disable Windows Error Recovery using the \u003ccode\u003e/set {default} recoveryenabled No\u003c/code\u003e command.\u003c/li\u003e\n\u003cli\u003eIgnore Boot Failures: The attacker uses \u003ccode\u003ebcdedit.exe\u003c/code\u003e to set the boot status policy to ignore all failures using the \u003ccode\u003e/set {default} bootstatuspolicy ignoreallfailures\u003c/code\u003e command.\u003c/li\u003e\n\u003cli\u003eSystem Impact: By modifying the boot configuration, the attacker inhibits system recovery, making it harder for the system to recover from errors or malicious activity.\u003c/li\u003e\n\u003cli\u003ePayload Execution: The attacker deploys and executes the primary malicious payload, such as ransomware, leveraging the modified boot configuration to maximize impact.\u003c/li\u003e\n\u003cli\u003eFinal Objective: The attacker achieves their final objective, which could include data encryption, data theft, or system disruption.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of boot configuration data can lead to significant system instability and data loss. In ransomware attacks, this technique prevents the system from recovering, increasing the likelihood of the victim paying the ransom. While the exact number of affected organizations is unknown, this technique is widely used in ransomware campaigns and can affect any Windows system if successfully executed.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Modification of Boot Configuration\u0026rdquo; Sigma rule to your SIEM and tune for your environment to detect the malicious use of \u003ccode\u003ebcdedit.exe\u003c/code\u003e described in this brief.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture \u003ccode\u003ebcdedit.exe\u003c/code\u003e executions and their command-line arguments (Sysmon Event ID 1).\u003c/li\u003e\n\u003cli\u003eInvestigate any detected instances of \u003ccode\u003ebcdedit.exe\u003c/code\u003e modifying boot configuration settings to determine legitimacy, as described in the rule\u0026rsquo;s \u0026ldquo;Triage and analysis\u0026rdquo; section.\u003c/li\u003e\n\u003cli\u003eMonitor process execution logs for unexpected processes running \u003ccode\u003ebcdedit.exe\u003c/code\u003e with arguments related to disabling recovery or ignoring boot failures.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T15:30:00Z","date_published":"2024-01-03T15:30:00Z","id":"/briefs/2024-01-bcdedit-boot-config-modification/","summary":"This rule identifies the use of bcdedit.exe to modify boot configuration data, which may be indicative of a destructive attack or ransomware activity aimed at inhibiting system recovery by disabling error recovery or ignoring boot failures.","title":"Detection of Bcdedit Boot Configuration Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-bcdedit-boot-config-modification/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike Falcon","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["impact","backup-deletion","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers, including ransomware groups, often attempt to remove or impair an organization\u0026rsquo;s ability to recover from an attack. One method to achieve this is by deleting Windows backup catalogs and system state backups using the \u003ccode\u003ewbadmin.exe\u003c/code\u003e utility. Windows Server Backup stores details about backups (what volumes are backed up and where the backups are located) in a backup catalog. Removing these catalogs renders backups unusable for recovery, increasing the impact of the attack. This technique is frequently observed in ransomware playbooks and other destructive attacks targeting Windows environments. This activity can be detected using endpoint detection and response (EDR) solutions, Windows Security Event Logs, and Sysmon.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system via phishing, exploiting a vulnerability, or using compromised credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to administrator level to execute wbadmin.exe.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003ewbadmin.exe\u003c/code\u003e with the \u003ccode\u003edelete catalog\u003c/code\u003e command to remove backup catalogs.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003ewbadmin.exe\u003c/code\u003e with the \u003ccode\u003edelete systemstatebackup\u003c/code\u003e command to remove system state backups.\u003c/li\u003e\n\u003cli\u003eThe attacker may also delete shadow copies using \u003ccode\u003evssadmin.exe\u003c/code\u003e or \u003ccode\u003ewmic.exe\u003c/code\u003e to further hinder recovery.\u003c/li\u003e\n\u003cli\u003eThe attacker deploys ransomware or initiates other destructive actions.\u003c/li\u003e\n\u003cli\u003eThe attacker encrypts or destroys data on the system and connected network shares.\u003c/li\u003e\n\u003cli\u003eThe attacker demands a ransom payment for data recovery, which is complicated by the deleted backups.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful deletion of backup catalogs and system state backups significantly impairs an organization\u0026rsquo;s ability to recover from a ransomware attack or other destructive event. This can lead to prolonged downtime, data loss, and financial losses associated with incident response and recovery efforts. While the number of direct victims of this specific technique is difficult to quantify, the impact is typically observed in conjunction with broader ransomware campaigns affecting organizations across various sectors.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging with Event ID 1 to capture \u003ccode\u003ewbadmin.exe\u003c/code\u003e executions and activate the first Sigma rule.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rules in this brief to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eMonitor Windows Security Event Logs for process creation events related to \u003ccode\u003ewbadmin.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of \u003ccode\u003ewbadmin.exe\u003c/code\u003e executing with \u003ccode\u003edelete\u003c/code\u003e arguments.\u003c/li\u003e\n\u003cli\u003eReview and harden account access controls to prevent unauthorized use of \u003ccode\u003ewbadmin.exe\u003c/code\u003e.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T15:00:00Z","date_published":"2024-01-03T15:00:00Z","id":"/briefs/2024-01-wbadmin-backup-deletion/","summary":"Adversaries may delete Windows backup catalogs and system state backups using wbadmin.exe to inhibit system recovery, often as part of ransomware or other destructive attacks.","title":"Windows Backup Deletion via Wbadmin","url":"https://feed.craftedsignal.io/briefs/2024-01-wbadmin-backup-deletion/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["enumeration","wmi","discovery","execution","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers can leverage the Windows Management Instrumentation (WMI) to execute commands for reconnaissance and enumeration within a compromised system. This involves spawning native Windows tools via the WMI Provider Service (WMIPrvSE). This activity is often used to gather system and network information in a stealthy manner, which could be part of a larger attack, such as lateral movement or privilege escalation. This behavior matters because it allows adversaries to gather information about the target environment without using easily detectable methods, potentially leading to further compromise.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to a Windows system (e.g., through phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uses WMI to execute a reconnaissance command.\u003c/li\u003e\n\u003cli\u003eWMIPrvSE.exe is invoked to execute the attacker\u0026rsquo;s specified command.\u003c/li\u003e\n\u003cli\u003eThe attacker executes commands such as \u003ccode\u003eipconfig.exe\u003c/code\u003e, \u003ccode\u003enet.exe\u003c/code\u003e, or \u003ccode\u003esysteminfo.exe\u003c/code\u003e via WMIPrvSE.exe to gather network configuration details, user information, and system information.\u003c/li\u003e\n\u003cli\u003eThe enumerated information is collected and potentially exfiltrated to a command and control server.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the gathered information to identify further targets within the network.\u003c/li\u003e\n\u003cli\u003eThe attacker moves laterally to other systems using stolen credentials or exploited vulnerabilities.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data exfiltration, ransomware deployment, or persistent access.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful execution of enumeration commands via WMIPrvSE allows attackers to gather sensitive information about the system and network environment. This information can be used to facilitate lateral movement, privilege escalation, and data theft, potentially leading to significant financial loss, reputational damage, and disruption of business operations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture the execution of enumeration commands (Data Source: Sysmon).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Enumeration Command Spawned via WMIPrvSE\u0026rdquo; to your SIEM to detect suspicious WMIPrvSE activity (Sigma rule).\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of WMIPrvSE spawning common enumeration tools such as \u003ccode\u003enet.exe\u003c/code\u003e, \u003ccode\u003eipconfig.exe\u003c/code\u003e, or \u003ccode\u003esysteminfo.exe\u003c/code\u003e (Sigma rule).\u003c/li\u003e\n\u003cli\u003eImplement network segmentation to limit the scope of potential lateral movement following successful enumeration (Attack Chain).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T15:00:00Z","date_published":"2024-01-03T15:00:00Z","id":"/briefs/2024-01-wmiprvse-enumeration/","summary":"This rule detects suspicious execution of system enumeration commands by the Windows Management Instrumentation Provider Service (WMIPrvSE), indicating potential reconnaissance or malicious activity on Windows systems.","title":"Suspicious Enumeration Commands Spawned via WMIPrvSE","url":"https://feed.craftedsignal.io/briefs/2024-01-wmiprvse-enumeration/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Crowdstrike FDR","Elastic Endgame","Elastic Defend"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","amsi-bypass","dll-hijacking","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","SentinelOne","CrowdStrike","Elastic"],"content_html":"\u003cp\u003eThe Antimalware Scan Interface (AMSI) is a Windows interface that allows applications and services to integrate with antimalware products. Attackers may attempt to bypass AMSI to execute malicious code without detection. This detection identifies the creation of the AMSI DLL (\u003ccode\u003eamsi.dll\u003c/code\u003e) in unusual locations, which is a common technique used to load a rogue AMSI module instead of the legitimate one. This technique can be used to evade detection by security products that rely on AMSI for scanning potentially malicious scripts and code. The rule is designed to work with data from Winlogbeat, Elastic Endpoint, Sysmon, Endgame, SentinelOne Cloud Funnel, Microsoft Defender XDR, and Crowdstrike.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through various means (e.g., phishing, exploit).\u003c/li\u003e\n\u003cli\u003eThe attacker determines the location of the legitimate \u003ccode\u003eamsi.dll\u003c/code\u003e file.\u003c/li\u003e\n\u003cli\u003eThe attacker identifies a writable directory where a malicious \u003ccode\u003eamsi.dll\u003c/code\u003e can be placed. This location must be in the search order of applications that use AMSI, such as PowerShell or other scripting hosts.\u003c/li\u003e\n\u003cli\u003eThe attacker copies or creates a malicious \u003ccode\u003eamsi.dll\u003c/code\u003e in the identified location. This rogue DLL is designed to bypass or disable AMSI functionality.\u003c/li\u003e\n\u003cli\u003eA process like PowerShell or another scripting host is launched. Because the malicious \u003ccode\u003eamsi.dll\u003c/code\u003e is in a higher-priority directory, it is loaded instead of the legitimate AMSI library.\u003c/li\u003e\n\u003cli\u003eThe launched process executes malicious code (e.g., PowerShell script).\u003c/li\u003e\n\u003cli\u003eBecause the rogue \u003ccode\u003eamsi.dll\u003c/code\u003e is loaded, AMSI scans are bypassed, allowing the malicious code to execute without detection.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful AMSI bypass can allow attackers to execute malicious code, such as malware, scripts, or exploits, without detection by antimalware products. This can lead to system compromise, data theft, or other malicious activities. The impact can range from a single compromised endpoint to a wider breach of an organization\u0026rsquo;s network.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable file creation monitoring with Sysmon or Elastic Defend to detect the creation of files, specifically DLLs, in unusual locations.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Suspicious Antimalware Scan Interface DLL Creation\u0026rdquo; to your SIEM to detect the creation of \u003ccode\u003eamsi.dll\u003c/code\u003e in non-standard paths. Tune the rule for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by examining the parent process, file path, and user context to determine if the activity is malicious.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T15:00:00Z","date_published":"2024-01-03T15:00:00Z","id":"/briefs/2024-01-amsi-dll-hijack/","summary":"An adversary may attempt to bypass AMSI by creating a rogue AMSI DLL in an unusual location to evade detection.","title":"Suspicious Antimalware Scan Interface DLL Creation","url":"https://feed.craftedsignal.io/briefs/2024-01-amsi-dll-hijack/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows","Citrix System32","MSACCESS.EXE","GTInstaller","Elastic Defend","SentinelOne Cloud Funnel","Microsoft Defender XDR","Crowdstrike FDR","Elastic Endgame"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","script-execution","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Citrix","Quokka.Works","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies the execution of scripts via HTML applications, leveraging Windows utilities like \u003ccode\u003erundll32.exe\u003c/code\u003e or \u003ccode\u003emshta.exe\u003c/code\u003e. Attackers often use this method to bypass process and signature-based defenses by proxying the execution of malicious content through legitimate, signed binaries. The detection focuses on specific command-line arguments and patterns associated with this technique, while also excluding known legitimate uses by applications such as Citrix System32 (\u003ccode\u003ewfshell.exe\u003c/code\u003e), Microsoft Access (\u003ccode\u003eMSACCESS.EXE\u003c/code\u003e), and Quokka.Works (\u003ccode\u003eGTInstaller.exe\u003c/code\u003e). This technique is used by attackers to execute malicious scripts without directly running them, thus evading traditional security measures. The detection rule analyzes process names, command-line arguments, parent processes, and file paths to identify potentially malicious activity indicative of defense evasion.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access through various means (e.g., phishing, drive-by download).\u003c/li\u003e\n\u003cli\u003eThe attacker leverages a malicious HTML application (HTA) file or a scriptlet (SCT) file.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003emshta.exe\u003c/code\u003e or \u003ccode\u003erundll32.exe\u003c/code\u003e to execute the malicious HTA or SCT file. The command line includes obfuscated or encoded script content.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003emshta.exe\u003c/code\u003e or \u003ccode\u003erundll32.exe\u003c/code\u003e process spawns a child process, such as \u003ccode\u003ecmd.exe\u003c/code\u003e or \u003ccode\u003epowershell.exe\u003c/code\u003e, to execute further commands.\u003c/li\u003e\n\u003cli\u003eThe spawned process executes malicious code, such as downloading and executing a payload.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves persistence by modifying registry keys or creating scheduled tasks.\u003c/li\u003e\n\u003cli\u003eThe attacker performs lateral movement by exploiting vulnerabilities or using stolen credentials.\u003c/li\u003e\n\u003cli\u003eThe final objective is achieved, such as data exfiltration, ransomware deployment, or system compromise.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to arbitrary code execution, allowing attackers to compromise the system, steal sensitive data, deploy ransomware, or establish a persistent foothold. Due to the nature of the technique, it can bypass many traditional security measures. The wide adoption of Windows and the inherent trust placed in signed binaries makes this a potent evasion technique. Failure to detect and prevent this attack can lead to significant financial and reputational damage for the targeted organization.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Script Execution via Microsoft HTML Application\u0026rdquo; to your SIEM to detect suspicious \u003ccode\u003emshta.exe\u003c/code\u003e and \u003ccode\u003erundll32.exe\u003c/code\u003e executions. Tune the rule by adding exceptions for known legitimate uses in your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to ensure the visibility required for the Sigma rules to function correctly.\u003c/li\u003e\n\u003cli\u003eMonitor process command lines for suspicious arguments like \u0026ldquo;script:eval\u0026rdquo;, \u0026ldquo;WScript.Shell\u0026rdquo;, and \u0026ldquo;mshta http\u0026rdquo; which are indicative of this technique.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of \u003ccode\u003emshta.exe\u003c/code\u003e and \u003ccode\u003erundll32.exe\u003c/code\u003e where they are not required for legitimate business purposes.\u003c/li\u003e\n\u003cli\u003eInvestigate and block any identified malicious HTA files or scriptlet URLs found in the command lines of detected processes.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T15:00:00Z","date_published":"2024-01-03T15:00:00Z","id":"/briefs/2024-01-script-execution-via-html-app/","summary":"Detects the execution of scripts via HTML applications using Windows utilities rundll32.exe or mshta.exe to bypass defenses by proxying execution of malicious content with signed binaries.","title":"Script Execution via Microsoft HTML Application","url":"https://feed.craftedsignal.io/briefs/2024-01-script-execution-via-html-app/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","proxy-execution","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Crowdstrike","Microsoft","SentinelOne"],"content_html":"\u003cp\u003eAttackers are leveraging the Console Window Host (conhost.exe) to proxy execution of commands, using the \u003ccode\u003e--headless\u003c/code\u003e argument to hide malicious activity. This technique allows adversaries to blend in with legitimate Windows processes, making detection more challenging. This behavior, often associated with defense evasion, involves using conhost.exe to execute commands such as PowerShell, cmd.exe, mshta, curl, and scripts. The activity can be seen across multiple environments including endpoints, Windows systems, and cloud platforms like Microsoft Defender XDR and SentinelOne. Defenders must differentiate between legitimate uses of conhost.exe, such as those by Winget-AutoUpdate or OpenSSH, and malicious proxy executions, which could indicate broader compromise.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system, possibly through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker executes a command that calls conhost.exe with the \u003ccode\u003e--headless\u003c/code\u003e argument.\u003c/li\u003e\n\u003cli\u003eConhost.exe is used to proxy the execution of a malicious command, such as PowerShell, cmd.exe, or mshta.\u003c/li\u003e\n\u003cli\u003eThe proxied command downloads a malicious payload from a remote server using tools like curl or bitsadmin.\u003c/li\u003e\n\u003cli\u003eThe downloaded payload is executed, establishing persistence on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the compromised system to move laterally within the network, compromising additional systems.\u003c/li\u003e\n\u003cli\u003eSensitive data is exfiltrated from the network to a remote server controlled by the attacker.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as deploying ransomware or stealing intellectual property.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to a complete compromise of the targeted system and potentially the entire network. This can result in data theft, financial loss, and reputational damage. The use of \u003ccode\u003econhost.exe\u003c/code\u003e for proxy execution makes it difficult to detect malicious activity, potentially allowing attackers to remain undetected for extended periods. The impact could range from individual workstation compromises to large-scale network breaches, affecting potentially hundreds or thousands of systems within an organization.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Proxy Execution via Console Window Host\u0026rdquo; Sigma rule to your SIEM and tune for your environment to detect suspicious \u003ccode\u003econhost.exe\u003c/code\u003e activity.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003econhost.exe\u003c/code\u003e with the \u003ccode\u003e--headless\u003c/code\u003e argument, focusing on the command-line arguments to identify potentially malicious commands.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of \u003ccode\u003econhost.exe\u003c/code\u003e executing suspicious scripts, downloaders, or task scheduler modifications to identify potential threats.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture detailed process execution information, as recommended in the setup instructions linked in the overview.\u003c/li\u003e\n\u003cli\u003eReview the investigation fields in the brief to understand the key data points for analyzing potential proxy execution attempts.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T15:00:00Z","date_published":"2024-01-03T15:00:00Z","id":"/briefs/2024-01-conhost-proxy-exec/","summary":"Adversaries abuse the Console Window Host (conhost.exe) with the `--headless` argument to proxy execution of malicious commands, evading detection by blending in with legitimate Windows software.","title":"Conhost Proxy Execution for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-conhost-proxy-exec/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows","firewall"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers commonly use the \u003ccode\u003enetsh.exe\u003c/code\u003e utility, a command-line scripting tool, to manage network configurations. Abusers leverage \u003ccode\u003enetsh.exe\u003c/code\u003e to disable or modify Windows Firewall rules, a built-in host-based firewall. This manipulation weakens the system\u0026rsquo;s defenses, allowing unauthorized network traffic and enabling lateral movement within the compromised environment. The activity allows for command and control communications and unhindered exploitation of internal resources. Defenders must monitor \u003ccode\u003enetsh.exe\u003c/code\u003e executions for unexpected firewall modifications.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial Access: An attacker gains initial access to a Windows system through various means such as phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003ePrivilege Escalation: The attacker escalates privileges to a level sufficient to modify firewall settings.\u003c/li\u003e\n\u003cli\u003eDiscovery: The attacker uses reconnaissance techniques to identify existing firewall rules.\u003c/li\u003e\n\u003cli\u003eDefense Evasion: The attacker uses \u003ccode\u003enetsh.exe\u003c/code\u003e to disable specific firewall rules, using commands like \u003ccode\u003enetsh advfirewall firewall set rule name=\u0026quot;rule_name\u0026quot; new enable=no\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eDefense Evasion: Alternatively, the attacker disables the entire firewall using \u003ccode\u003enetsh advfirewall set allprofiles state off\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eLateral Movement: With the firewall weakened, the attacker moves laterally to other systems on the network.\u003c/li\u003e\n\u003cli\u003eCommand and Control: The attacker establishes command and control channels, which may now be unimpeded by firewall rules.\u003c/li\u003e\n\u003cli\u003eImpact: The attacker achieves their objectives, such as data exfiltration, ransomware deployment, or further compromise of the network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful disabling of Windows Firewall rules can lead to significant security breaches. Attackers can move laterally within the network, compromise additional systems, and exfiltrate sensitive data. The impact can range from data loss and financial damage to reputational harm and legal consequences. The defense evasion enables attackers to establish persistent command and control channels, maintain a long-term presence within the compromised environment and conduct further malicious activities.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging to monitor \u003ccode\u003enetsh.exe\u003c/code\u003e executions and related command-line arguments to support detections.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rules in this brief to your SIEM to detect attempts to disable Windows Firewall rules via \u003ccode\u003enetsh.exe\u003c/code\u003e. Tune the rules for your specific environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rules, focusing on identifying the user account, process execution chain, and the specific firewall rules being modified.\u003c/li\u003e\n\u003cli\u003eImplement strict access controls to limit the number of users with the privileges necessary to modify firewall settings.\u003c/li\u003e\n\u003cli\u003eRegularly review and audit firewall configurations to ensure they are properly configured and have not been tampered with.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:30:00Z","date_published":"2024-01-03T14:30:00Z","id":"/briefs/2024-01-disable-windows-firewall-rules/","summary":"Detection of adversaries disabling Windows Firewall rules using the `netsh.exe` command-line tool to weaken defenses and facilitate unauthorized network activity.","title":"Windows Firewall Disabled via Netsh","url":"https://feed.craftedsignal.io/briefs/2024-01-disable-windows-firewall-rules/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR"],"_cs_severities":["medium"],"_cs_tags":["persistence","startup","windows","attack.persistence"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eAdversaries may abuse the Windows Startup folder to maintain persistence in an environment. The Startup folder is a special folder in Windows where programs added to this folder are executed during account logon without user interaction. This rule identifies script engines (wscript.exe, cscript.exe) creating files or the creation of script files with specific extensions (vbs, vbe, wsh, wsf, js, jse, sct, hta, ps1, bat, cmd) in the Startup folder. The rule is designed for data generated by Elastic Defend and also supports Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system.\u003c/li\u003e\n\u003cli\u003eThe attacker creates a malicious script (e.g., VBScript, PowerShell) designed to execute arbitrary commands.\u003c/li\u003e\n\u003cli\u003eThe attacker identifies the Startup folder path for a specific user or all users.\u003c/li\u003e\n\u003cli\u003eThe attacker creates a shortcut file (e.g., .lnk) or a script file directly within the Startup folder.\u003c/li\u003e\n\u003cli\u003eThe shortcut or script is configured to execute the malicious script.\u003c/li\u003e\n\u003cli\u003eThe system is restarted or the user logs in.\u003c/li\u003e\n\u003cli\u003eThe operating system automatically executes the script located in the Startup folder.\u003c/li\u003e\n\u003cli\u003eThe malicious script executes, allowing the attacker to perform actions such as installing malware, establishing persistence, or exfiltrating data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack leveraging the Startup folder persistence mechanism allows the attacker to maintain unauthorized access to a compromised system. This can lead to the execution of malicious code, installation of malware, data theft, and further compromise of the network. The impact is significant, potentially affecting all users who log into the system.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Script Creation in Startup Directory\u0026rdquo; to your SIEM and tune for your environment to identify the creation of suspicious scripts in the Startup folder.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Script Execution via Startup Directory\u0026rdquo; to your SIEM and tune for your environment to identify script execution from the Startup directory.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) to collect necessary data for the detections above.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by these rules promptly to identify and remediate potential persistence attempts.\u003c/li\u003e\n\u003cli\u003eBlock the file extensions listed in the rule query (vbs, vbe, wsh, wsf, js, jse, sct, hta, ps1, bat, cmd) from being written to the startup folder via application control policies where possible.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:30:00Z","date_published":"2024-01-03T14:30:00Z","id":"/briefs/2024-01-startup-folder-persistence/","summary":"This rule identifies script engines creating files or the creation of script files in the Windows Startup folder, a persistence technique used by adversaries to automatically execute scripts upon user login.","title":"Suspicious Scripts in the Startup Directory","url":"https://feed.craftedsignal.io/briefs/2024-01-startup-folder-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["initial-access","execution","windows","powershell","script"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies PowerShell execution initiated by Windows Script Host processes (cscript.exe or wscript.exe). Attackers often use Windows Script Host (WSH) to execute malicious scripts as an initial access method. These scripts can act as droppers for second-stage payloads or download tools and utilities necessary for further compromise. The rule focuses on the parent-child process relationship between WSH and PowerShell, highlighting a common technique used to bypass security controls and execute arbitrary commands on a compromised system. This activity is relevant to defenders as it represents a potential entry point for various attacks, including malware deployment and data exfiltration. The detection logic is based on process execution events observed in Windows environments and is designed to work with data from Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe user receives a phishing email with a malicious attachment (e.g., a .vbs or .js file).\u003c/li\u003e\n\u003cli\u003eThe user opens the attachment, which is processed by either wscript.exe or cscript.exe.\u003c/li\u003e\n\u003cli\u003eThe scripting engine executes the embedded malicious code.\u003c/li\u003e\n\u003cli\u003eThe script downloads a PowerShell script from a remote server or contains an embedded, obfuscated PowerShell command.\u003c/li\u003e\n\u003cli\u003eThe script uses wscript.exe or cscript.exe to launch powershell.exe to execute the downloaded or embedded PowerShell script.\u003c/li\u003e\n\u003cli\u003ePowerShell executes, performing malicious actions such as downloading additional payloads, modifying system settings, or establishing persistence.\u003c/li\u003e\n\u003cli\u003ePowerShell attempts to connect to external command-and-control servers to receive further instructions.\u003c/li\u003e\n\u003cli\u003eThe attacker gains initial access to the system and can proceed with lateral movement, data exfiltration, or other malicious activities.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to initial access, allowing attackers to deploy malware, steal sensitive information, or perform other malicious activities. The impact can range from data breaches and financial losses to reputational damage. The severity depends on the attacker\u0026rsquo;s objectives and the level of access they gain. The number of affected systems depends on the scope of the phishing campaign or other initial access methods used to deliver the malicious script.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture the necessary event data for the rules below.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rules in this brief to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate process execution chains where cscript.exe or wscript.exe spawn powershell.exe using the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eImplement email security measures to block phishing emails with script attachments.\u003c/li\u003e\n\u003cli\u003eMonitor network connections originating from PowerShell processes for suspicious outbound traffic.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:30:00Z","date_published":"2024-01-03T14:30:00Z","id":"/briefs/2024-01-script-powershell-execution/","summary":"Detection of PowerShell processes launched by cscript.exe or wscript.exe, indicative of potential malicious initial access or execution attempts.","title":"Suspicious PowerShell Execution via Windows Script Host","url":"https://feed.craftedsignal.io/briefs/2024-01-script-powershell-execution/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Defend"],"_cs_severities":["low"],"_cs_tags":["persistence","user-account-creation","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers may create new accounts (both local and domain) to maintain access to victim systems. This rule identifies the usage of \u003ccode\u003enet.exe\u003c/code\u003e to create new accounts on Windows systems. The detection logic focuses on process execution events where \u003ccode\u003enet.exe\u003c/code\u003e or \u003ccode\u003enet1.exe\u003c/code\u003e are executed with arguments indicative of user creation, specifically the \u0026lsquo;user\u0026rsquo; argument in conjunction with either the \u0026lsquo;/ad\u0026rsquo; or \u0026lsquo;/add\u0026rsquo; flags. While account creation is a common administrative task, suspicious executions, especially those initiated by unusual parent processes or accounts, warrant further investigation. This rule is designed for data generated by Elastic Defend but also supports third-party data sources like CrowdStrike, Microsoft Defender XDR, and SentinelOne Cloud Funnel, enhancing its applicability across various security environments.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through various means, such as exploiting a vulnerability or using stolen credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker opens a command prompt or PowerShell session.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003enet.exe\u003c/code\u003e or \u003ccode\u003enet1.exe\u003c/code\u003e to create a new user account. The command includes the \u003ccode\u003euser\u003c/code\u003e argument along with \u003ccode\u003e/add\u003c/code\u003e or \u003ccode\u003e/ad\u003c/code\u003e flags. For example: \u003ccode\u003enet user \u0026lt;username\u0026gt; \u0026lt;password\u0026gt; /add\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker may add the newly created user to privileged groups, such as \u003ccode\u003eAdministrators\u003c/code\u003e or \u003ccode\u003eDomain Admins\u003c/code\u003e, to elevate privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the new account to move laterally within the network, accessing sensitive data or systems.\u003c/li\u003e\n\u003cli\u003eThe attacker establishes persistence by configuring the new account to be a service account or adding it to local administrator groups.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to unauthorized access to sensitive data, lateral movement within the network, and long-term persistence on compromised systems. The impact is often determined by the privileges assigned to the newly created account. If the attacker adds the account to the \u003ccode\u003eAdministrators\u003c/code\u003e group, they can effectively take full control of the affected system. In a domain environment, creating a domain account can lead to wider compromise across the entire network.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process-creation logging to capture the necessary events for the rules below.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rules in this brief to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of \u003ccode\u003enet.exe\u003c/code\u003e or \u003ccode\u003enet1.exe\u003c/code\u003e creating user accounts, especially when initiated by unusual parent processes.\u003c/li\u003e\n\u003cli\u003eMonitor for newly created accounts being added to privileged groups.\u003c/li\u003e\n\u003cli\u003eReview the triage and analysis steps in the rule\u0026rsquo;s original documentation for guidance on investigating and responding to potential incidents.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:00:00Z","date_published":"2024-01-03T14:00:00Z","id":"/briefs/2024-01-user-account-creation/","summary":"This rule identifies attempts to create new users on Windows systems using net.exe, a common tactic used by attackers to increase access or establish persistence.","title":"Windows User Account Creation via Net.exe","url":"https://feed.craftedsignal.io/briefs/2024-01-user-account-creation/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["persistence","startup","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eAttackers often leverage the Windows Startup folder to maintain persistence, as any executable placed in this folder will automatically run when a user logs into the system. This technique is particularly effective because it requires no user interaction and can easily be automated. This rule detects when processes commonly abused by attackers, such as cmd.exe, powershell.exe, or mshta.exe, write or modify files within the Startup folders. The rule focuses on identifying unauthorized persistence mechanisms and helps defenders uncover potentially compromised systems. By monitoring file creation events in the Startup folders by suspicious processes, this detection aims to catch malicious activity early in the attack chain.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes a command shell (e.g., \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e) on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the command shell to write a malicious executable or script file to one of the Windows Startup folders (\u003ccode\u003eC:\\\\Users\\\\*\\\\AppData\\\\Roaming\\\\Microsoft\\\\Windows\\\\Start Menu\\\\Programs\\\\Startup\\\\*\u003c/code\u003e or \u003ccode\u003eC:\\\\ProgramData\\\\Microsoft\\\\Windows\\\\Start Menu\\\\Programs\\\\StartUp\\\\*\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the file attributes (e.g., using \u003ccode\u003eattrib.exe\u003c/code\u003e) to hide the file or make it more difficult to detect.\u003c/li\u003e\n\u003cli\u003eThe attacker schedules a reboot or waits for the user to log off and back on.\u003c/li\u003e\n\u003cli\u003eUpon user logon, the malicious executable or script in the Startup folder is automatically executed.\u003c/li\u003e\n\u003cli\u003eThe malicious code establishes persistence, potentially downloading additional payloads or establishing a command and control (C2) channel.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistent access to the compromised system, enabling further malicious activities such as data theft or lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation leads to persistent access on the compromised system, allowing attackers to maintain their foothold even after system reboots. This can lead to data exfiltration, installation of ransomware, or further propagation within the network. The number of affected systems depends on the scope of the initial compromise and the attacker\u0026rsquo;s ability to move laterally. Sectors commonly targeted by persistence techniques include finance, healthcare, and government.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) to capture file creation events, as referenced in the \u003ca href=\"#setup\"\u003esetup instructions\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSuspicious Process Writing to Startup Folder\u003c/code\u003e to your SIEM to detect suspicious processes creating files in the startup folder, and tune for your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule to determine if the activity is malicious, referencing the \u003ca href=\"#note\"\u003einvestigation guide\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eBlock the processes listed in the rule (\u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e, etc.) from writing to the startup folders if legitimate use is not required.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:00:00Z","date_published":"2024-01-03T14:00:00Z","id":"/briefs/2024-01-startup-persistence/","summary":"Adversaries may establish persistence by writing malicious files to the Windows Startup folder, allowing them to automatically execute upon user logon; this detection identifies suspicious processes creating files in these locations.","title":"Suspicious Process Writing to Startup Folder for Persistence","url":"https://feed.craftedsignal.io/briefs/2024-01-startup-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Office","Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel","LogiOptions","Sidekick.vsto"],"_cs_severities":["medium"],"_cs_tags":["office-addins","phishing","initial-access"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Logitech","Elastic","SentinelOne"],"content_html":"\u003cp\u003eAttackers are increasingly leveraging malicious Microsoft Office Add-Ins to gain initial access and persistence on victim systems. These add-ins, often delivered through phishing campaigns, contain embedded malicious code. This detection identifies unusual execution patterns, such as Office applications (WINWORD.EXE, EXCEL.EXE, POWERPNT.EXE, MSACCESS.EXE, VSTOInstaller.exe) launching add-ins (wll, xll, ppa, ppam, xla, xlam, vsto) from suspicious paths like Temp or Downloads directories, or with atypical parent processes (explorer.exe, OpenWith.exe, cmd.exe, powershell.exe). The detection logic filters out known benign activities to minimize false positives, focusing on anomalies indicative of malicious intent, such as installations of Logitech software. This activity matters because successful exploitation can lead to arbitrary code execution, data theft, and further compromise of the victim\u0026rsquo;s network.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eA user receives a phishing email containing a malicious Microsoft Office document.\u003c/li\u003e\n\u003cli\u003eThe user opens the document, which prompts them to enable macros or install an add-in.\u003c/li\u003e\n\u003cli\u003eThe malicious add-in (wll, xll, ppa, ppam, xla, xlam, vsto) is downloaded from a remote server or dropped into a suspicious directory, such as %TEMP% or %APPDATA%.\u003c/li\u003e\n\u003cli\u003eThe user executes an Office application (WINWORD.EXE, EXCEL.EXE, POWERPNT.EXE, MSACCESS.EXE), which loads the malicious add-in.\u003c/li\u003e\n\u003cli\u003eThe malicious add-in executes arbitrary code, potentially downloading and executing a second-stage payload.\u003c/li\u003e\n\u003cli\u003eThe add-in may establish persistence by modifying registry keys or creating scheduled tasks.\u003c/li\u003e\n\u003cli\u003eThe attacker gains initial access to the system and can perform reconnaissance, lateral movement, and data exfiltration.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, which could include data theft, ransomware deployment, or intellectual property theft.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to complete system compromise, data theft, and potential ransomware deployment. Organizations across all sectors are at risk, particularly those with a high volume of email traffic. The use of malicious Office Add-Ins provides attackers with a persistent foothold within the victim\u0026rsquo;s environment, allowing for long-term data collection and disruption of business operations. This can lead to significant financial losses, reputational damage, and legal liabilities.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eOffice Add-In Loaded From Suspicious Path\u003c/code\u003e to detect add-ins loaded from temporary or download directories based on \u003ccode\u003eprocess.args\u003c/code\u003e and \u003ccode\u003eprocess.name\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eOffice Add-In Loaded By Suspicious Parent\u003c/code\u003e to detect add-ins loaded by \u003ccode\u003ecmd.exe\u003c/code\u003e or \u003ccode\u003epowershell.exe\u003c/code\u003e based on \u003ccode\u003eprocess.parent.name\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of \u003ccode\u003eVSTOInstaller.exe\u003c/code\u003e executing with the \u003ccode\u003e/Uninstall\u003c/code\u003e argument, as this may indicate suspicious activity, correlating with the exclusion rule in the provided query.\u003c/li\u003e\n\u003cli\u003eMonitor for Office applications launching add-ins with parent processes of \u003ccode\u003eexplorer.exe\u003c/code\u003e or \u003ccode\u003eOpenWith.exe\u003c/code\u003e using process creation logs and the provided query logic.\u003c/li\u003e\n\u003cli\u003eImplement stricter email filtering to prevent phishing emails containing malicious Office documents from reaching end-users.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:00:00Z","date_published":"2024-01-03T14:00:00Z","id":"/briefs/2024-01-office-addins/","summary":"This rule detects suspicious execution of Microsoft Office applications launching Office Add-Ins from unusual paths or with atypical parent processes, potentially indicating an attempt to gain initial access via a malicious phishing campaign.","title":"Suspicious Execution via Microsoft Office Add-Ins","url":"https://feed.craftedsignal.io/briefs/2024-01-office-addins/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["MsMpEng.exe","Windows Defender","TeamViewer","SentinelOne Cloud Funnel","Microsoft Defender XDR"],"_cs_severities":["medium"],"_cs_tags":["remotemonologue","defense-evasion","persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","TeamViewer","SentinelOne"],"content_html":"\u003cp\u003eThe RemoteMonologue attack technique abuses Component Object Model (COM) objects to coerce authentication from a remote system. This is achieved by modifying the \u003ccode\u003eRunAs\u003c/code\u003e registry value associated with a COM object. Setting this value to \u0026ldquo;Interactive User\u0026rdquo; forces the COM object to run under the context of the interactive user, enabling attackers to hijack sessions and potentially escalate privileges. This technique is often used as a defense evasion or persistence mechanism by adversaries after gaining initial access to a system. The attack involves modifying registry keys associated with COM objects to trigger NTLM authentication coercion. This can be used for lateral movement and gaining access to sensitive resources. This rule is designed to detect registry modifications indicative of the RemoteMonologue attack.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial Access: An attacker gains initial access to the target system through unspecified means.\u003c/li\u003e\n\u003cli\u003eIdentify COM Objects: The attacker identifies suitable COM objects for abuse.\u003c/li\u003e\n\u003cli\u003eModify Registry: The attacker modifies the registry to set the \u003ccode\u003eRunAs\u003c/code\u003e value for the selected COM object to \u003ccode\u003eInteractive User\u003c/code\u003e. This involves modifying the registry path \u003ccode\u003eHKCR\\AppID\\{Clsid}\\RunAs\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eTrigger COM Object Execution: The attacker triggers the execution of the modified COM object, potentially through a remote procedure call or other inter-process communication mechanisms.\u003c/li\u003e\n\u003cli\u003eAuthentication Coercion: The execution of the COM object triggers NTLM authentication to a system controlled by the attacker.\u003c/li\u003e\n\u003cli\u003eRelay Attack: The attacker relays the coerced NTLM authentication to gain access to other resources on the network.\u003c/li\u003e\n\u003cli\u003eSession Hijacking: Successful relay leads to session hijacking, allowing the attacker to impersonate the user.\u003c/li\u003e\n\u003cli\u003eLateral Movement/Privilege Escalation: The attacker uses the hijacked session for lateral movement or privilege escalation within the network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful RemoteMonologue attack can lead to unauthorized access to sensitive systems and data. By coercing authentication and hijacking sessions, attackers can bypass security controls and escalate their privileges within the network. The scope of the impact depends on the privileges of the hijacked user account and the resources accessible to that account. This attack can enable lateral movement, data exfiltration, and other malicious activities.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect RemoteMonologue Registry Modification\u003c/code\u003e to your SIEM to identify suspicious registry modifications related to COM object hijacking.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to capture the necessary data for the Sigma rules to function effectively.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by reviewing the registry event logs and identifying the user account and process responsible for the registry modification.\u003c/li\u003e\n\u003cli\u003eImplement enhanced monitoring on critical systems to detect any attempts to modify COM object registry settings.\u003c/li\u003e\n\u003cli\u003eBlock the attack by ensuring \u0026ldquo;RunAs\u0026rdquo; value is not set to \u0026ldquo;Interactive User\u0026rdquo;.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:00:00Z","date_published":"2024-01-03T14:00:00Z","id":"/briefs/2024-01-remotemonologue-regmod/","summary":"This rule detects potential RemoteMonologue attacks by identifying attempts to perform session hijacking via COM object registry modification, specifically when the RunAs value is set to Interactive User.","title":"Potential RemoteMonologue Attack via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-remotemonologue-regmod/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Windows Security Event Logs"],"_cs_severities":["medium"],"_cs_tags":["execution","defense-evasion","windows","process-execution"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eThis detection rule identifies instances of process execution originating from suspicious default Windows directories. Attackers often exploit these locations to conceal malware, leveraging the implicit trust associated with system or application paths to evade security measures. This tactic is employed to make malicious executions appear less conspicuous. The rule focuses on detecting specific processes, including \u003ccode\u003ewscript.exe\u003c/code\u003e, \u003ccode\u003ecscript.exe\u003c/code\u003e, \u003ccode\u003erundll32.exe\u003c/code\u003e, \u003ccode\u003eregsvr32.exe\u003c/code\u003e, and others, when they are executed from unusual directories, such as \u003ccode\u003eC:\\\\PerfLogs\\\\\u003c/code\u003e, \u003ccode\u003eC:\\\\Users\\\\Public\\\\\u003c/code\u003e, and \u003ccode\u003eC:\\\\Windows\\\\Tasks\\\\\u003c/code\u003e. The intent is to highlight anomalous process behaviors that deviate from expected norms, providing early warning of potential malicious activity. The detection logic also includes filters to reduce false positives by excluding known legitimate executables and command line arguments from the specified directories.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through various means such as phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker uploads or drops a malicious payload into a suspicious directory like \u003ccode\u003eC:\\\\Users\\\\Public\\\\\u003c/code\u003e or \u003ccode\u003eC:\\\\Windows\\\\Tasks\\\\\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a legitimate Windows utility such as \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e, or \u003ccode\u003ewscript.exe\u003c/code\u003e to execute the malicious payload.\u003c/li\u003e\n\u003cli\u003eThe executed script or binary performs malicious actions, such as establishing persistence.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to evade detection by masquerading the malicious activity as legitimate system processes.\u003c/li\u003e\n\u003cli\u003eThe malware may attempt to communicate with a command-and-control server.\u003c/li\u003e\n\u003cli\u003eThe malware may perform lateral movement within the network.\u003c/li\u003e\n\u003cli\u003eThe final objective of the attacker is to exfiltrate sensitive data or cause damage to the system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to malware infection, data compromise, and system instability. Attackers can establish persistent access, escalate privileges, and perform lateral movement within the network. The impact ranges from minor disruptions to significant data breaches depending on the attacker\u0026rsquo;s objectives and the compromised system\u0026rsquo;s role within the organization. The targeted sectors are broad, as this technique is applicable across various industries and organizational sizes.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Execution from Unusual Directory - Command Line\u0026rdquo; to your SIEM and tune for your environment to detect suspicious process executions from unusual directories.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rule, focusing on the process execution chain and command-line arguments.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging with command line arguments to provide the necessary data for the Sigma rule (reference log source in rule).\u003c/li\u003e\n\u003cli\u003eRegularly review and update the list of suspicious directories in the Sigma rule to reflect changes in your environment.\u003c/li\u003e\n\u003cli\u003eImplement application whitelisting to restrict the execution of unauthorized applications from unusual directories.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:00:00Z","date_published":"2024-01-03T14:00:00Z","id":"/briefs/2024-01-03-execution-from-unusual-directory/","summary":"This rule identifies process execution from suspicious default Windows directories, which adversaries may abuse to hide malware in trusted paths to evade defenses.","title":"Execution from Unusual Directory - Command Line","url":"https://feed.craftedsignal.io/briefs/2024-01-03-execution-from-unusual-directory/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","CrowdStrike"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","wsl","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","SentinelOne","CrowdStrike"],"content_html":"\u003cp\u003eAttackers may enable the Windows Subsystem for Linux (WSL) to run Linux applications and tools directly on Windows, potentially bypassing security controls and hindering detection. This involves using the Dism.exe utility to enable the \u0026ldquo;Microsoft-Windows-Subsystem-Linux\u0026rdquo; feature. By leveraging WSL, adversaries can execute malicious code, access Windows resources, and perform various malicious activities while blending in with legitimate system processes. The use of WSL provides an environment where traditional Windows-based security solutions may have limited visibility, thus offering a way to evade detection. This activity has been observed as a post-exploitation technique, used after initial access to a compromised system.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through methods such as phishing, exploiting vulnerabilities, or using compromised credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker executes Dism.exe (Deployment Image Servicing and Management tool).\u003c/li\u003e\n\u003cli\u003eDism.exe is invoked with the command-line argument to enable the \u0026ldquo;Microsoft-Windows-Subsystem-Linux\u0026rdquo; feature.\u003c/li\u003e\n\u003cli\u003eThe system processes the Dism.exe command and enables WSL.\u003c/li\u003e\n\u003cli\u003eThe attacker installs a Linux distribution (e.g., Ubuntu, Kali) within the WSL environment.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the WSL environment to execute Linux-based tools and scripts for reconnaissance, lateral movement, or data exfiltration.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the WSL environment to interact with Windows resources or execute Windows commands.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as stealing sensitive data or establishing persistence on the compromised system.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful enablement of WSL can lead to a compromised Windows system being used as a platform for Linux-based attacks. This can result in data theft, system compromise, and further propagation of malicious activity within the network. The use of WSL can make it difficult to detect malicious activity since it allows attackers to blend Linux-based attacks with normal Windows operations. The lack of visibility into the WSL environment by traditional Windows security tools can lead to prolonged periods of undetected malicious activity.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor process creation events for the execution of \u003ccode\u003eDism.exe\u003c/code\u003e with command-line arguments that include \u003ccode\u003eMicrosoft-Windows-Subsystem-Linux\u003c/code\u003e to detect WSL enablement attempts (see Sigma rule \u003ccode\u003eDetect WSL Enablement via Dism\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture detailed command-line information for processes, which is crucial for detecting this activity (Sysmon Event ID 1).\u003c/li\u003e\n\u003cli\u003eImplement the provided Sigma rule to detect suspicious usage of the DISM utility to enable WSL. Tune the rule based on your environment to minimize false positives.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule \u003ccode\u003eDetect WSL Enablement via Dism\u003c/code\u003e to determine the legitimacy of the activity.\u003c/li\u003e\n\u003cli\u003eMonitor network connections originating from WSL processes for suspicious outbound traffic.\u003c/li\u003e\n\u003cli\u003eConsider blocking the execution of Dism.exe if WSL is not a sanctioned tool in your environment.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-wsl-enabled-via-dism/","summary":"Adversaries may enable and use Windows Subsystem for Linux (WSL) using the Microsoft Dism utility to evade detection on Windows systems by running Linux applications and tools.","title":"Windows Subsystem for Linux Enabled via Dism Utility","url":"https://feed.craftedsignal.io/briefs/2024-01-wsl-enabled-via-dism/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows","Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Crowdstrike FDR","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","persistence","lateral-movement","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThe legacy Windows AT command allows scheduling tasks for execution. While deprecated since Windows 8 and Windows Server 2012, it remains present for backwards compatibility. Attackers may enable the AT command through registry modifications to achieve persistence or lateral movement within a network. This technique bypasses modern security controls and can be difficult to detect without specific monitoring. The detection rule monitors registry changes enabling this command, flagging potential misuse by checking specific registry paths and values indicative of enabling the AT command. The use of this command allows an attacker to execute commands with elevated privileges, potentially compromising the entire system.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system, possibly through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to enable the AT command by modifying the registry.\u003c/li\u003e\n\u003cli\u003eThe registry key \u003ccode\u003eHKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Schedule\\Configuration\\EnableAt\u003c/code\u003e is modified to a value of \u0026ldquo;1\u0026rdquo; or \u0026ldquo;0x00000001\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the AT command to schedule a malicious task.\u003c/li\u003e\n\u003cli\u003eThe scheduled task executes a command or script, such as downloading and executing malware.\u003c/li\u003e\n\u003cli\u003eThe malware establishes persistence on the system.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the compromised system as a pivot point for lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eEnabling the AT command can lead to unauthorized task scheduling, malware execution, persistence, and lateral movement within a network. Successful exploitation can compromise sensitive data, disrupt operations, and grant attackers persistent access to critical systems. The use of a deprecated command makes it harder to detect, increasing the impact.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor registry events for modifications to \u003ccode\u003eHKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Schedule\\Configuration\\EnableAt\u003c/code\u003e as described in the rule overview.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Scheduled Tasks AT Command Enabled\u0026rdquo; to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation and registry event logging to activate the rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rule \u0026ldquo;Scheduled Tasks AT Command Enabled\u0026rdquo; for suspicious activity.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-at-command-enabled/","summary":"Attackers may enable the deprecated Windows AT command via registry modification to achieve local persistence or lateral movement.","title":"Windows Scheduled Tasks AT Command Enabled via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-at-command-enabled/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","persistence","root certificate","mitm"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eAttackers can install malicious root certificates to subvert trust controls and bypass security measures. Once a malicious root certificate is installed, attackers can sign malicious files, making them appear as legitimate software from trusted vendors like Microsoft. This allows the attacker to execute code undetected and maintain persistence on the system. Furthermore, a rogue root certificate can be used in adversary-in-the-middle attacks to decrypt SSL traffic, enabling the collection of sensitive data. This activity is typically achieved through registry modifications. Monitoring for these modifications can help security teams identify potential compromise attempts.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system, possibly through phishing or exploiting a software vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker elevates privileges to administrator or SYSTEM level, required to modify the trusted root certificate store.\u003c/li\u003e\n\u003cli\u003eThe attacker uses tools like certutil.exe or PowerShell to import a malicious root certificate into the Windows registry.\u003c/li\u003e\n\u003cli\u003eThe registry keys \u003ccode\u003eHKLM\\Software\\Microsoft\\SystemCertificates\\Root\\Certificates\u003c/code\u003e or \u003ccode\u003eHKLM\\Software\\Policies\\Microsoft\\SystemCertificates\\Root\\Certificates\u003c/code\u003e are modified to add the new certificate.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the newly installed root certificate to sign malicious executables or scripts.\u003c/li\u003e\n\u003cli\u003eThe signed malicious files are executed, bypassing signature-based detection mechanisms.\u003c/li\u003e\n\u003cli\u003eThe attacker intercepts and decrypts SSL traffic, collecting sensitive data like credentials or financial information.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence by using the trusted certificate to repeatedly sign and execute malicious code.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful installation of a malicious root certificate allows attackers to bypass security controls, leading to the execution of arbitrary code and potential data theft. This can result in significant data breaches, financial losses, and reputational damage. Attackers can use this technique to maintain a long-term presence on compromised systems, making detection and remediation more challenging. While no specific victim counts are available, the technique is broadly applicable across many sectors and can affect any organization running Windows systems.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Root Certificate Modification\u0026rdquo; to your SIEM to detect registry modifications related to root certificate installation.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to provide the necessary data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rule, focusing on processes modifying the registry keys related to root certificates.\u003c/li\u003e\n\u003cli\u003eReview the \u0026ldquo;False Positives\u0026rdquo; section in the rule documentation to tune the Sigma rule for your environment.\u003c/li\u003e\n\u003cli\u003eMonitor network traffic for suspicious SSL decryption activity following the detection of a root certificate modification.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-root-cert-modification/","summary":"The modification of root certificates on Windows systems by unauthorized processes can allow attackers to masquerade malicious files as valid signed components and intercept/decrypt SSL traffic, leading to defense evasion and data collection.","title":"Windows Root Certificate Modification Detection","url":"https://feed.craftedsignal.io/briefs/2024-01-root-cert-modification/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows","firewall"],"_cs_type":"advisory","_cs_vendors":["Microsoft","CrowdStrike","SentinelOne","Elastic"],"content_html":"\u003cp\u003eAttackers can leverage the \u003ccode\u003enetsh.exe\u003c/code\u003e utility to modify Windows Firewall settings, specifically enabling Network Discovery. This setting allows a host to broadcast its presence and services, making it easier for attackers to identify potential targets within the network for lateral movement. The behavior is often a post-exploitation technique to weaken host-based defenses after gaining initial access. The modification uses netsh.exe, a command-line scripting utility for managing network configurations. This activity can be easily scripted and automated, making it a common step in reconnaissance and lateral movement playbooks. Defenders should monitor for unauthorized use of \u003ccode\u003enetsh.exe\u003c/code\u003e to modify firewall settings.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker gains initial access to a Windows host.\u003c/li\u003e\n\u003cli\u003eAttacker executes \u003ccode\u003enetsh.exe\u003c/code\u003e with elevated privileges.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003enetsh.exe\u003c/code\u003e is used to modify the Windows Firewall configuration.\u003c/li\u003e\n\u003cli\u003eThe specific command executed enables Network Discovery using the \u003ccode\u003enetsh advfirewall firewall set rule group=\u0026quot;Network Discovery\u0026quot; new enable=Yes\u003c/code\u003e syntax.\u003c/li\u003e\n\u003cli\u003eThe firewall rule group \u0026ldquo;Network Discovery\u0026rdquo; is modified to allow inbound and outbound traffic.\u003c/li\u003e\n\u003cli\u003eThe compromised host begins sending out broadcast messages, advertising its presence and services on the network.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the information gathered to identify other vulnerable systems on the network.\u003c/li\u003e\n\u003cli\u003eThe attacker moves laterally to other systems based on the discovery information.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to easily enumerate and identify other vulnerable systems within the network. This can lead to rapid lateral movement, further compromising the environment. The risk is heightened when the compromised host has access to sensitive data or critical systems. There is no specific victim count or sector targeted mentioned in the provided source.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Enable Host Network Discovery via Netsh\u0026rdquo; to your SIEM to detect the use of \u003ccode\u003enetsh.exe\u003c/code\u003e to enable network discovery (see rule below).\u003c/li\u003e\n\u003cli\u003eEnable Windows Firewall logging and monitor for changes to firewall rules, specifically those related to Network Discovery.\u003c/li\u003e\n\u003cli\u003eReview and restrict the use of \u003ccode\u003enetsh.exe\u003c/code\u003e to authorized personnel and systems only.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-enable-network-discovery/","summary":"Attackers can enable host network discovery via netsh.exe to weaken host firewall settings, facilitating lateral movement by identifying other systems on the network.","title":"Windows Host Network Discovery Enabled via Netsh","url":"https://feed.craftedsignal.io/briefs/2024-01-enable-network-discovery/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","CrowdStrike","SentinelOne Cloud Funnel","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","powershell","firewall","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers often attempt to disable or modify system firewalls to evade network restrictions and facilitate lateral movement within a compromised environment. The Windows Firewall, a built-in component, provides host-based traffic filtering. Disabling it allows unrestricted communication, aiding command and control activities and hindering detection efforts. This activity is commonly achieved through PowerShell, leveraging cmdlets like \u003ccode\u003eSet-NetFirewallProfile\u003c/code\u003e. The rule focuses on detecting the use of this specific cmdlet to disable the Windows Firewall, alerting defenders to potential defense evasion attempts. This technique is valuable to attackers across various attack vectors, especially after initial access has been established.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial Access: An attacker gains initial access through methods such as phishing or exploiting a vulnerability in a network-facing application.\u003c/li\u003e\n\u003cli\u003ePrivilege Escalation (if necessary): The attacker escalates privileges to gain the necessary permissions to modify firewall settings.\u003c/li\u003e\n\u003cli\u003ePowerShell Execution: The attacker executes PowerShell, either through an interactive session or a script.\u003c/li\u003e\n\u003cli\u003eDisable Firewall Profile: The attacker uses the \u003ccode\u003eSet-NetFirewallProfile\u003c/code\u003e cmdlet with parameters such as \u003ccode\u003e-Enabled False\u003c/code\u003e to disable the firewall for all, public, domain, or private profiles.\u003c/li\u003e\n\u003cli\u003eNetwork Reconnaissance: With the firewall disabled, the attacker performs network reconnaissance to identify valuable assets and potential lateral movement paths.\u003c/li\u003e\n\u003cli\u003eLateral Movement: The attacker moves laterally to other systems on the network, exploiting trust relationships or vulnerabilities.\u003c/li\u003e\n\u003cli\u003eCommand and Control: The attacker establishes command and control channels to communicate with compromised systems and exfiltrate sensitive data.\u003c/li\u003e\n\u003cli\u003eData Exfiltration or Further Exploitation: The attacker exfiltrates sensitive data or continues to exploit the environment based on their objectives.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful disabling of the Windows Firewall can lead to unrestricted lateral movement within a network, allowing attackers to compromise additional systems and exfiltrate sensitive data. This can result in data breaches, financial losses, and reputational damage. While the source does not specify the number of affected organizations, any environment relying on Windows Firewall for network segmentation is at risk.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rule to your SIEM to detect the use of \u003ccode\u003eSet-NetFirewallProfile\u003c/code\u003e with the \u003ccode\u003e-Enabled False\u003c/code\u003e parameter (see Sigma rule below).\u003c/li\u003e\n\u003cli\u003eEnable process creation logging on Windows endpoints to capture PowerShell executions (reference the logsource in the Sigma rule).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule to determine the legitimacy of the firewall modification activity.\u003c/li\u003e\n\u003cli\u003eReview and enforce the principle of least privilege to limit the number of users with permissions to modify firewall settings.\u003c/li\u003e\n\u003cli\u003eConsider implementing additional network segmentation and monitoring controls to detect and prevent lateral movement even if the Windows Firewall is disabled.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-powershell-firewall-disable/","summary":"Attackers may disable the Windows firewall or its rules using the `Set-NetFirewallProfile` PowerShell cmdlet to enable lateral movement and command and control activity.","title":"Windows Firewall Disabled via PowerShell","url":"https://feed.craftedsignal.io/briefs/2024-01-powershell-firewall-disable/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","powershell","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","CrowdStrike","SentinelOne","Elastic"],"content_html":"\u003cp\u003eAttackers may attempt to evade detection by modifying Windows Defender\u0026rsquo;s configuration to exclude specific files, folders, or processes from scanning. This is often achieved by using PowerShell commands to add exclusions. The tactic allows malware to operate without being detected by the built-in antivirus solution. Observed as early as 2018 with Trickbot disabling Windows Defender, this technique remains relevant today. This activity can be performed using \u003ccode\u003eAdd-MpPreference\u003c/code\u003e or \u003ccode\u003eSet-MpPreference\u003c/code\u003e commands in PowerShell, specifying exclusions by path or process name. Detecting these modifications is critical for maintaining the integrity of endpoint security. The scope of targeting ranges from individual workstations to entire networks.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system via an undisclosed method.\u003c/li\u003e\n\u003cli\u003eThe attacker executes PowerShell with administrative privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the \u003ccode\u003eAdd-MpPreference\u003c/code\u003e or \u003ccode\u003eSet-MpPreference\u003c/code\u003e cmdlet to add an exclusion.\u003c/li\u003e\n\u003cli\u003eThe exclusion specifies a file path, folder, or process that should be ignored by Windows Defender.\u003c/li\u003e\n\u003cli\u003eWindows Defender is reconfigured to ignore the specified item.\u003c/li\u003e\n\u003cli\u003eThe attacker deploys or executes malware in the excluded location.\u003c/li\u003e\n\u003cli\u003eThe malware operates without interference from Windows Defender.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data theft or lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to operate undetected on compromised systems, leading to potential data breaches, lateral movement within the network, and deployment of ransomware. While the exact number of victims is unknown, this technique is widely used by various threat actors, impacting organizations across various sectors. The lack of detection can lead to prolonged periods of compromise, increasing the potential damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Windows Defender Exclusions Added via PowerShell\u0026rdquo; to your SIEM to detect suspicious PowerShell commands used to add exclusions.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging with command line auditing to capture the necessary event data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eRegularly review Windows Defender exclusion lists to identify any unauthorized or suspicious entries.\u003c/li\u003e\n\u003cli\u003eInvestigate any PowerShell process that uses \u003ccode\u003eAdd-MpPreference\u003c/code\u003e or \u003ccode\u003eSet-MpPreference\u003c/code\u003e with exclusion parameters, as identified by the provided Sigma rule.\u003c/li\u003e\n\u003cli\u003eMonitor for processes and file modifications within excluded directories.\u003c/li\u003e\n\u003cli\u003eConfigure alerts to notify security teams when new Windows Defender exclusions are added.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-defender-exclusion-powershell/","summary":"Adversaries may attempt to bypass Windows Defender's capabilities by using PowerShell to add exclusions for folders or processes, and this activity can be detected by monitoring PowerShell command lines that use `Add-MpPreference` or `Set-MpPreference` with exclusion parameters.","title":"Windows Defender Exclusions Added via PowerShell","url":"https://feed.craftedsignal.io/briefs/2024-01-defender-exclusion-powershell/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR"],"_cs_severities":["low"],"_cs_tags":["persistence","registry_modification","werfault"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers can abuse the Windows Error Reporting (Werfault) service to establish persistence on a compromised system. This is achieved by modifying the ReflectDebugger registry key. When Werfault is executed with the \u003ccode\u003e-pr\u003c/code\u003e parameter, it will execute the debugger specified in the ReflectDebugger registry key. This allows attackers to execute arbitrary code every time the Windows Error Reporting utility is triggered. The technique involves modifying specific registry paths associated with the ReflectDebugger. This behavior has been documented as a persistence mechanism in malware analysis reports.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system through unspecified means.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to modify the Windows Error Reporting ReflectDebugger registry key.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the ReflectDebugger value within one of the following registry paths: \u003ccode\u003eHKLM\\Software\\Microsoft\\Windows\\Windows Error Reporting\\Hangs\\ReflectDebugger\u003c/code\u003e, \u003ccode\u003e\\REGISTRY\\MACHINE\\Software\\Microsoft\\Windows\\Windows Error Reporting\\Hangs\\ReflectDebugger\u003c/code\u003e, or \u003ccode\u003eMACHINE\\Software\\Microsoft\\Windows\\Windows Error Reporting\\Hangs\\ReflectDebugger\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker sets the ReflectDebugger value to a malicious executable or script.\u003c/li\u003e\n\u003cli\u003eThe attacker triggers Werfault.exe with the \u003ccode\u003e-pr\u003c/code\u003e parameter, either manually or through a system event.\u003c/li\u003e\n\u003cli\u003eWerfault.exe executes the attacker-controlled code specified in the ReflectDebugger registry value.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves persistence, as the malicious code is executed each time Werfault is triggered with the \u003ccode\u003e-pr\u003c/code\u003e parameter.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to achieve persistence on the targeted system. This can lead to the execution of arbitrary code, potentially resulting in data theft, further malware installation, or complete system compromise. The impact is limited by the permissions of the Werfault process. While no specific victim counts are available, this technique can affect any Windows system where the attacker can modify the registry.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eWerfault ReflectDebugger Registry Modification\u003c/code\u003e to detect unauthorized modifications to the ReflectDebugger registry key (logsource: \u003ccode\u003eregistry_set\u003c/code\u003e, rule title).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to detect the execution of Werfault with the \u003ccode\u003e-pr\u003c/code\u003e parameter.\u003c/li\u003e\n\u003cli\u003eMonitor registry events for changes to the specific ReflectDebugger paths mentioned in the overview section (\u003ccode\u003eHKLM\\Software\\Microsoft\\Windows\\Windows Error Reporting\\Hangs\\ReflectDebugger\u003c/code\u003e).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-werfault-reflectdebugger-persistence/","summary":"Attackers may establish persistence by modifying the ReflectDebugger registry key associated with Windows Error Reporting to execute arbitrary code when Werfault is invoked with the '-pr' parameter.","title":"Werfault ReflectDebugger Persistence via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-werfault-reflectdebugger-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["persistence","windows","registry modification"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies processes that modify the Windows services registry key directly, bypassing the standard Windows APIs. This behavior can signify an adversary\u0026rsquo;s attempt to establish persistence stealthily by creating new services or altering existing ones in an unexpected manner. The detection logic focuses on changes to the \u003ccode\u003eServiceDLL\u003c/code\u003e and \u003ccode\u003eImagePath\u003c/code\u003e values within specific registry paths associated with service configurations. This rule is designed for data generated by Elastic Defend and also supports Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon Registry Events. The rule helps security analysts identify potentially malicious activity related to service manipulation, which can lead to persistent access and control over compromised systems. The rule excludes known legitimate processes and paths to minimize false positives, focusing on anomalous registry modifications.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through various means (e.g., phishing, exploitation of a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to gain administrative access, allowing them to modify the registry.\u003c/li\u003e\n\u003cli\u003eThe attacker directly modifies the \u003ccode\u003eHKLM\\SYSTEM\\ControlSet*\\Services\\*\\ServiceDLL\u003c/code\u003e or \u003ccode\u003eHKLM\\SYSTEM\\ControlSet*\\Services\\*\\ImagePath\u003c/code\u003e registry keys to point to a malicious DLL or executable.\u003c/li\u003e\n\u003cli\u003eThe attacker\u0026rsquo;s malicious DLL or executable is configured to run as a service, ensuring persistence across system reboots.\u003c/li\u003e\n\u003cli\u003eThe compromised service starts automatically during system startup or manually when triggered by the attacker.\u003c/li\u003e\n\u003cli\u003eThe malicious service executes arbitrary code, providing the attacker with persistent control over the system.\u003c/li\u003e\n\u003cli\u003eThe attacker may use the compromised service to perform further malicious activities, such as data exfiltration or lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to achieve persistence on the compromised system, maintaining access even after reboots or user logoffs. This can lead to long-term control over the system, enabling attackers to perform various malicious activities, including data theft, deployment of ransomware, or use of the system as a foothold for further attacks within the network. The severity is further amplified if critical services are targeted, potentially leading to system instability or denial of service.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon registry event logging to capture the necessary data for this detection (Data Source: Sysmon).\u003c/li\u003e\n\u003cli\u003eDeploy the provided Sigma rules to your SIEM to detect unusual service registry modifications (Sigma rules).\u003c/li\u003e\n\u003cli\u003eTune the Sigma rules by adding exceptions for legitimate software installations or updates that modify service registry keys directly (Sigma rules).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rules, focusing on processes modifying the \u003ccode\u003eServiceDLL\u003c/code\u003e or \u003ccode\u003eImagePath\u003c/code\u003e registry values (Sigma rules).\u003c/li\u003e\n\u003cli\u003eReview endpoint protection policies to ensure that similar unauthorized registry modifications are detected and blocked in the future (Response and remediation).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-unusual-registry-persistence/","summary":"Detection of processes modifying the Windows services registry key directly, potentially indicating stealthy persistence attempts via abnormal service creation or modification.","title":"Unusual Persistence via Services Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-unusual-registry-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["execution","windows","cmd.exe"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne"],"content_html":"\u003cp\u003eThis detection rule identifies unusual parent processes spawning \u003ccode\u003ecmd.exe\u003c/code\u003e on Windows systems. While \u003ccode\u003ecmd.exe\u003c/code\u003e is a legitimate command-line interpreter, adversaries can exploit it by launching it from atypical parent processes to execute malicious commands stealthily. The rule focuses on identifying \u003ccode\u003ecmd.exe\u003c/code\u003e instances spawned by uncommon parent processes like \u003ccode\u003elsass.exe\u003c/code\u003e, \u003ccode\u003ecsrss.exe\u003c/code\u003e, and \u003ccode\u003eregsvr32.exe\u003c/code\u003e, which may indicate unauthorized or suspicious activity. The rule is based on the EQL query language and is designed for data generated by Elastic Defend, Microsoft Defender XDR, and SentinelOne Cloud Funnel, as well as Sysmon event logs. This detection helps in early threat detection by flagging anomalies in process relationships.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system (e.g., through phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes a malicious payload on the system.\u003c/li\u003e\n\u003cli\u003eThe malicious payload spawns \u003ccode\u003ecmd.exe\u003c/code\u003e to execute commands.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003ecmd.exe\u003c/code\u003e process is launched by an unusual parent process, such as \u003ccode\u003elsass.exe\u003c/code\u003e or \u003ccode\u003ecsrss.exe\u003c/code\u003e, instead of typical processes like \u003ccode\u003eexplorer.exe\u003c/code\u003e or \u003ccode\u003ecmd.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003ecmd.exe\u003c/code\u003e process executes malicious commands, such as downloading additional payloads, modifying system configurations, or exfiltrating data.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the \u003ccode\u003ecmd.exe\u003c/code\u003e process to establish persistence on the system by creating scheduled tasks or modifying registry keys.\u003c/li\u003e\n\u003cli\u003eThe attacker performs lateral movement by using \u003ccode\u003ecmd.exe\u003c/code\u003e to access other systems on the network.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data theft, system compromise, or ransomware deployment.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack leveraging an unusual parent process for \u003ccode\u003ecmd.exe\u003c/code\u003e can lead to a range of adverse outcomes, including system compromise, data theft, and ransomware deployment. The impact can vary depending on the attacker\u0026rsquo;s objectives and the level of access they gain. Without proper detection and response, organizations can suffer financial losses, reputational damage, and operational disruption. The severity is dependent on the specific commands executed via the spawned command prompt.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided EQL query to your Elastic Security environment to detect unusual parent processes for \u003ccode\u003ecmd.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture the necessary data for this detection and ensure proper configuration.\u003c/li\u003e\n\u003cli\u003eTune the EQL query for your environment by excluding legitimate parent processes, identified in the \u0026ldquo;False positive analysis\u0026rdquo; section, that may trigger false positives (e.g., \u003ccode\u003eSearchIndexer.exe\u003c/code\u003e, \u003ccode\u003eWUDFHost.exe\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by this rule to determine the nature of the malicious activity and the extent of the compromise.\u003c/li\u003e\n\u003cli\u003eImplement enhanced monitoring and logging for \u003ccode\u003ecmd.exe\u003c/code\u003e and its parent processes to detect similar anomalies in the future.\u003c/li\u003e\n\u003cli\u003eConsider deploying endpoint detection and response (EDR) solutions like Elastic Defend, Microsoft Defender XDR, or SentinelOne Cloud Funnel for enhanced visibility and protection.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-unusual-cmd-parent/","summary":"The detection rule identifies cmd.exe instances spawned by uncommon parent processes, such as lsass.exe, csrss.exe, or regsvr32.exe, which may indicate unauthorized or suspicious activity, thus aiding in early threat detection.","title":"Unusual Parent Process for cmd.exe","url":"https://feed.craftedsignal.io/briefs/2024-01-unusual-cmd-parent/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","SentinelOne Cloud Funnel","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["uac-bypass","privilege-escalation","com","ieinstal"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection rule identifies a User Account Control (UAC) bypass technique that abuses the Internet Explorer Add-On Installer (ieinstal.exe) to launch malicious programs with elevated privileges. Attackers exploit elevated COM interfaces to circumvent UAC, allowing for stealthy code execution. The specific behavior involves executing a program from a temporary directory using ieinstal.exe with the \u003ccode\u003e-Embedding\u003c/code\u003e argument. This bypass can be utilized to perform various malicious activities, including installing malware, modifying system settings, or establishing persistence. The targeted systems are Windows endpoints where UAC is enabled. This technique matters because it allows attackers to gain unauthorized access with elevated permissions, undermining standard Windows security controls.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the system, possibly through phishing or other means.\u003c/li\u003e\n\u003cli\u003eThe attacker drops a malicious executable into a temporary directory, such as \u003ccode\u003eC:\\Users\\\u0026lt;user\u0026gt;\\AppData\\Local\\Temp\\IDC*.tmp\\\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker invokes \u003ccode\u003eieinstal.exe\u003c/code\u003e with the \u003ccode\u003e-Embedding\u003c/code\u003e argument, specifying the path to the malicious executable.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003eieinstal.exe\u003c/code\u003e, running with elevated privileges, launches the malicious executable due to COM object handling.\u003c/li\u003e\n\u003cli\u003eThe malicious executable executes with elevated privileges, bypassing UAC prompts.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages elevated privileges to perform malicious activities, such as installing malware or modifying system settings.\u003c/li\u003e\n\u003cli\u003eThe attacker establishes persistence to maintain elevated access across system reboots.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of this UAC bypass technique allows attackers to execute arbitrary code with elevated privileges, bypassing security controls designed to prevent unauthorized system modifications. This can lead to the installation of malware, data theft, or complete system compromise. The severity of the impact is high, as it grants attackers significant control over the affected system.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;UAC Bypass Attempt via Elevated COM Internet Explorer Add-On Installer\u0026rdquo; to your SIEM to detect potential UAC bypass attempts.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture the necessary events for the Sigma rule to function correctly.\u003c/li\u003e\n\u003cli\u003eMonitor process execution from temporary directories, specifically those matching the pattern \u003ccode\u003eC:\\\\*\\\\AppData\\\\*\\\\Temp\\\\IDC*.tmp\\\\*.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of \u003ccode\u003eieinstal.exe\u003c/code\u003e being executed with the \u003ccode\u003e-Embedding\u003c/code\u003e argument, as this is a key indicator of the UAC bypass attempt.\u003c/li\u003e\n\u003cli\u003eImplement application whitelisting to prevent unauthorized executables from running, particularly those in temporary directories.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-03-uac-bypass-ieinstal/","summary":"This threat brief details a UAC bypass technique leveraging the Internet Explorer Add-On Installer (ieinstal.exe) and Component Object Model (COM) to execute arbitrary code with elevated privileges.","title":"UAC Bypass Attempt via Elevated COM Internet Explorer Add-On Installer","url":"https://feed.craftedsignal.io/briefs/2024-01-03-uac-bypass-ieinstal/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","Elastic Endgame","Windows Security Event Logs","Crowdstrike"],"_cs_severities":["medium"],"_cs_tags":["execution","persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","Crowdstrike"],"content_html":"\u003cp\u003eThe rule detects suspicious usage of \u003ccode\u003emofcomp.exe\u003c/code\u003e, a command-line tool used to compile Managed Object Format (MOF) files. Attackers can abuse MOF files to manipulate the Windows Management Instrumentation (WMI) repository by building malicious WMI scripts for persistence or execution. This can be achieved by creating their own namespaces and classes within WMI or establishing persistence through WMI Event Subscriptions. The rule identifies unusual mofcomp.exe activity by filtering out legitimate processes and focusing on unusual executions, excluding known safe parent processes like \u003ccode\u003eScenarioEngine.exe\u003c/code\u003e and system accounts (\u003ccode\u003eS-1-5-18\u003c/code\u003e). This detection is designed to work with data from Elastic Defend, Microsoft Defender XDR, Crowdstrike, and Windows Security Event Logs. The rule aims to detect potential misuse of WMI for malicious purposes, enhancing the visibility of attacker techniques for execution and persistence.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system (e.g., through phishing or exploitation of a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uploads a malicious MOF file to the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003emofcomp.exe\u003c/code\u003e to compile the malicious MOF file.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003emofcomp.exe\u003c/code\u003e processes the MOF file, creating new namespaces and classes or modifying existing ones in the WMI repository.\u003c/li\u003e\n\u003cli\u003eIf the MOF file creates a WMI Event Subscription, it triggers the execution of a malicious script or binary when a specific event occurs.\u003c/li\u003e\n\u003cli\u003eThe malicious script or binary executes, performing actions such as installing malware, creating backdoors, or exfiltrating data.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence through the WMI Event Subscription, ensuring continued access even after system reboots.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation via malicious MOF files can lead to persistent access, code execution, and system compromise. Attackers can use this technique to install malware, create backdoors, or steal sensitive data. The rule aims to detect early stages of such attacks, preventing significant damage. By establishing persistence, attackers can maintain long-term control over the compromised system, evading traditional detection methods.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rules to your SIEM to detect suspicious \u003ccode\u003emofcomp.exe\u003c/code\u003e activity and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging and command-line auditing on Windows systems to capture necessary events for the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rules, focusing on unusual MOF file paths, parent processes, and user accounts.\u003c/li\u003e\n\u003cli\u003eReview and monitor WMI namespaces and classes for unauthorized modifications or additions following any detected suspicious \u003ccode\u003emofcomp.exe\u003c/code\u003e activity.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-mofcomp-activity/","summary":"This rule detects suspicious mofcomp.exe activity, which attackers may leverage MOF files to manipulate the Windows Management Instrumentation (WMI) repository for execution and persistence by filtering out legitimate processes and focusing on unusual executions, excluding known safe parent processes and system accounts.","title":"Suspicious Mofcomp Activity","url":"https://feed.craftedsignal.io/briefs/2024-01-mofcomp-activity/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","SentinelOne Cloud Funnel","CrowdStrike FDR","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["persistence","defense-evasion","registry-modification","ssp"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers can abuse the Windows Security Support Provider (SSP) mechanism to establish persistence on a compromised system. SSPs are DLLs loaded into the Local Security Authority Subsystem Service (LSASS) process, which handles authentication in Windows. By modifying specific registry keys related to SSP configuration, attackers can force LSASS to load malicious DLLs at startup, effectively creating a persistent backdoor. This technique is often used to maintain unauthorized access to a system even after a reboot. The registry keys of interest are \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\Security Packages\u003c/code\u003e and \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\OSConfig\\Security Packages\u003c/code\u003e. Successful exploitation allows the attacker to intercept and manipulate authentication credentials.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through an exploit or compromised credentials (not detailed in source).\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to gain administrative rights on the system.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the registry key \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\Security Packages\u003c/code\u003e to include a path to a malicious DLL.\u003c/li\u003e\n\u003cli\u003eAlternatively, the attacker modifies the registry key \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\OSConfig\\Security Packages\u003c/code\u003e to include a path to a malicious DLL.\u003c/li\u003e\n\u003cli\u003eThe attacker triggers a system reboot, or restarts the LSASS process, causing the malicious SSP DLL to be loaded.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL intercepts authentication credentials and exfiltrates them or performs other malicious actions.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistent access to the system, even after reboots.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to achieve persistence and potentially compromise sensitive credentials handled by LSASS. This can lead to lateral movement within the network, data exfiltration, and further system compromise. The impact is significant as it bypasses standard security measures and provides a persistent foothold for malicious activities.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Suspicious SSP Registry Modification\u0026rdquo; to your SIEM to detect unauthorized modifications to SSP registry keys.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to provide the necessary data for the Sigma rule to function.\u003c/li\u003e\n\u003cli\u003eContinuously monitor for unexpected processes writing to the \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\Security Packages\u003c/code\u003e and \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\OSConfig\\Security Packages\u003c/code\u003e registry keys.\u003c/li\u003e\n\u003cli\u003eReview and whitelist legitimate software installers that frequently modify these registry entries to reduce false positives as mentioned in the brief.\u003c/li\u003e\n\u003cli\u003eEnsure access controls and permissions are strictly enforced to limit unauthorized modification of critical registry paths related to Security Support Providers.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-ssp-registry-modification/","summary":"Adversaries may modify the Windows Security Support Provider (SSP) configuration in the registry to establish persistence or evade defenses.","title":"Suspicious Modifications to Windows Security Support Provider (SSP) Registry","url":"https://feed.craftedsignal.io/briefs/2024-01-ssp-registry-modification/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Antimalware Service Executable","Windows Defender","Microsoft Security Client","Elastic Defend","CrowdStrike Falcon","Microsoft Defender XDR","Sysmon"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","execution","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","Elastic"],"content_html":"\u003cp\u003eThis detection identifies suspicious execution of the Microsoft Antimalware Service Executable (MsMpEng.exe) from non-standard paths or renamed instances. Attackers may attempt to evade defenses through DLL side-loading or by masquerading as the antimalware process. This technique is used to blend in with legitimate system activity and avoid detection by security tools. This rule is designed to detect instances where MsMpEng.exe is executed from unexpected locations or has been renamed, potentially indicating malicious activity. The rule leverages process monitoring data to identify deviations from the expected execution patterns of the antimalware service. This behavior has been seen associated with ransomware attacks, such as REvil.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system, potentially through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker drops a malicious payload onto the system, placing it in a non-standard directory, such as a temporary folder or a user\u0026rsquo;s profile directory.\u003c/li\u003e\n\u003cli\u003eThe attacker renames or copies the legitimate MsMpEng.exe to the malicious payload\u0026rsquo;s location.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the renamed or copied MsMpEng.exe from the non-standard location. This is intended to mimic legitimate activity and evade detection.\u003c/li\u003e\n\u003cli\u003eThe malicious MsMpEng.exe then loads a malicious DLL through DLL side-loading, which executes arbitrary code within the context of the antimalware process.\u003c/li\u003e\n\u003cli\u003eThe malicious code performs actions such as disabling security controls, escalating privileges, or establishing persistence.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the compromised system to move laterally within the network, compromising additional systems.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data exfiltration or ransomware deployment.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to complete system compromise, including the disabling of security controls, data theft, and ransomware deployment. This can result in significant financial losses, reputational damage, and disruption of business operations. Identifying and responding to this type of attack is critical to prevent further damage. The Sophos article references the REvil ransomware attack which impacted hundreds of businesses.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture process execution events, including image path and command-line arguments, which are essential for detecting this behavior.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rules provided in this brief to your SIEM to detect suspicious MsMpEng.exe execution from unusual paths or renamed instances.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by these rules to determine the legitimacy of the MsMpEng.exe execution and identify any potential malicious activity.\u003c/li\u003e\n\u003cli\u003eMonitor process execution events for instances where the process name is \u0026ldquo;MsMpEng.exe\u0026rdquo; but the executable path is outside the standard Windows Defender or Microsoft Security Client directories.\u003c/li\u003e\n\u003cli\u003eReview the references provided for additional context and guidance on investigating this type of activity.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-windefend-unusual-path/","summary":"Detects suspicious execution of the Microsoft Antimalware Service Executable (MsMpEng.exe) from non-standard paths or renamed instances, which may indicate an attempt to evade defenses through DLL side-loading or masquerading.","title":"Suspicious Microsoft Antimalware Service Executable Execution","url":"https://feed.craftedsignal.io/briefs/2024-01-windefend-unusual-path/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["defense-evasion","execution","credential-access","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne"],"content_html":"\u003cp\u003eThe Windows Subsystem for Linux (WSL) enables users to run Linux binaries natively on Windows, creating an opportunity for adversaries to evade detection by executing malicious Linux commands without triggering traditional Windows security alerts. This technique involves leveraging WSL\u0026rsquo;s bash shell to perform actions that might otherwise be flagged if executed directly within the Windows environment. This alert focuses on detecting suspicious behaviors indicative of malicious use of WSL, such as unauthorized access to sensitive files, use of network tools, or unusual command-line arguments. This can be used to facilitate lateral movement, data exfiltration, or other malicious activities. The Qualys blog post \u0026ldquo;Implications of Windows Subsystem for Linux for Adversaries \u0026amp; Defenders\u0026rdquo; (2022-03-22) describes this attack vector in detail.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system.\u003c/li\u003e\n\u003cli\u003eThe attacker enables WSL if it is not already enabled.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003ewsl.exe\u003c/code\u003e to start a Linux environment.\u003c/li\u003e\n\u003cli\u003eInside the WSL environment, the attacker uses \u003ccode\u003ebash\u003c/code\u003e to execute malicious commands.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to access sensitive files such as \u003ccode\u003e/etc/shadow\u003c/code\u003e or \u003ccode\u003e/etc/passwd\u003c/code\u003e to gather credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker uses network tools like \u003ccode\u003ecurl\u003c/code\u003e to download or upload malicious payloads.\u003c/li\u003e\n\u003cli\u003eThe attacker executes scripts to establish persistence within the WSL environment.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the compromised WSL environment to move laterally to other systems or exfiltrate data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation via WSL can lead to a variety of negative outcomes, including unauthorized access to sensitive information, credential compromise, and lateral movement within the network. While specific victim counts are unavailable, this technique can significantly increase the attack surface and reduce the effectiveness of traditional Windows-based security measures, affecting organizations across various sectors.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture \u003ccode\u003ewsl.exe\u003c/code\u003e and \u003ccode\u003ebash.exe\u003c/code\u003e executions (reference: Sysmon Event ID 1 setup in rule setup section).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Suspicious WSL Activity\u0026rdquo; to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eMonitor process command lines for suspicious arguments used with \u003ccode\u003ewsl.exe\u003c/code\u003e, such as access to \u003ccode\u003e/etc/shadow\u003c/code\u003e or \u003ccode\u003e/etc/passwd\u003c/code\u003e (reference: Sigma rule selection criteria).\u003c/li\u003e\n\u003cli\u003eInvestigate and whitelist legitimate uses of WSL within your environment to reduce false positives (reference: False positive analysis in the rule description).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-wsl-bash-exec/","summary":"Adversaries may leverage the Windows Subsystem for Linux (WSL) to execute malicious Linux commands, bypassing traditional Windows security measures, detected by monitoring process execution and command-line arguments.","title":"Suspicious Execution via Windows Subsystem for Linux","url":"https://feed.craftedsignal.io/briefs/2024-01-wsl-bash-exec/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","process-injection","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies potentially malicious attempts to evade endpoint security solutions by monitoring the parent processes of security executables. Adversaries may employ process hollowing or other code injection techniques to inject malicious code into legitimate processes, such as \u003ccode\u003eesensor.exe\u003c/code\u003e or \u003ccode\u003eelastic-endpoint.exe\u003c/code\u003e, to avoid detection. The rule flags unexpected parent processes based on deviations from expected behavior, excluding known benign paths and arguments to minimize false positives. This activity is important for defenders as successful evasion can lead to significant compromise of systems and data. The rule supports various data sources, including Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, and Sysmon, providing broad coverage across different security ecosystems.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system through an unknown vector.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to inject malicious code into a legitimate endpoint security process (\u003ccode\u003eesensor.exe\u003c/code\u003e or \u003ccode\u003eelastic-endpoint.exe\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe malicious code is injected using process hollowing or similar techniques.\u003c/li\u003e\n\u003cli\u003eThe endpoint security process is launched by a suspicious parent process outside of known legitimate paths (e.g., not in \u003ccode\u003eC:\\Program Files\\Elastic\\*\u003c/code\u003e or \u003ccode\u003eC:\\Windows\\System32\\*\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe injected code executes within the context of the endpoint security process, potentially disabling or bypassing security controls.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the compromised endpoint security process to perform further malicious activities, such as lateral movement or data exfiltration.\u003c/li\u003e\n\u003cli\u003eThe endpoint security solution\u0026rsquo;s ability to detect and respond to threats is impaired, allowing the attacker to operate undetected.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation via process injection can lead to a significant degradation of endpoint security posture. Attackers can disable or bypass security controls, allowing them to perform malicious activities such as data theft, ransomware deployment, or lateral movement undetected. The impact can range from individual system compromise to widespread network breaches, depending on the scope of the attack.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSuspicious Endpoint Security Parent Process\u003c/code\u003e to your SIEM to detect anomalous parent-child process relationships involving endpoint security executables.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to provide detailed process execution data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by reviewing the parent process executable path, command-line arguments, and historical activity.\u003c/li\u003e\n\u003cli\u003eAdd legitimate but unusual parent process paths to the Sigma rule\u0026rsquo;s exclusion list to reduce false positives, as described in the rule\u0026rsquo;s \u003ccode\u003eFalse positive analysis\u003c/code\u003e section.\u003c/li\u003e\n\u003cli\u003eCorrelate alerts from this rule with other security events from data sources like Elastic Endgame, Microsoft Defender XDR, or Sysmon, as recommended in the rule\u0026rsquo;s \u003ccode\u003ePossible investigation steps\u003c/code\u003e section.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-03-suspicious-endpoint-parent/","summary":"This rule detects suspicious parent processes of endpoint security solutions such as Elastic Defend, Microsoft Defender, and SentinelOne, indicating potential process hollowing or code injection attempts to evade detection.","title":"Suspicious Endpoint Security Parent Process Detected","url":"https://feed.craftedsignal.io/briefs/2024-01-03-suspicious-endpoint-parent/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["solarwinds","defense-evasion","registry-modification","supply-chain"],"_cs_type":"advisory","_cs_vendors":["SolarWinds","Microsoft","SentinelOne","Crowdstrike","Elastic"],"content_html":"\u003cp\u003eThis threat brief focuses on the detection of SolarWinds processes attempting to disable services by modifying their registry start type. This activity is associated with defense evasion tactics, potentially linked to initial access via supply chain compromise, similar to the SUNBURST campaign. The behavior involves SolarWinds binaries, such as \u003ccode\u003eSolarWinds.BusinessLayerHost*.exe\u003c/code\u003e and \u003ccode\u003eNetFlowService*.exe\u003c/code\u003e, manipulating registry entries related to service start configurations. This technique can be used to impair or disable security tools and services, allowing attackers to operate more freely within a compromised environment.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial compromise of the SolarWinds Orion platform, potentially through a supply chain attack.\u003c/li\u003e\n\u003cli\u003eDeployment of a malicious module or payload within the SolarWinds environment.\u003c/li\u003e\n\u003cli\u003eExecution of a SolarWinds process, such as \u003ccode\u003eSolarWinds.BusinessLayerHost*.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe SolarWinds process modifies the registry to change the start type of a service.\u003c/li\u003e\n\u003cli\u003eThe registry modification targets the \u003ccode\u003eHKLM\\SYSTEM\\ControlSet*\\Services\\*\\Start\u003c/code\u003e path.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003eStart\u003c/code\u003e value is set to \u0026ldquo;4\u0026rdquo; or \u0026ldquo;0x00000004\u0026rdquo;, which disables the targeted service.\u003c/li\u003e\n\u003cli\u003eDisabling critical security services allows the attacker to evade detection and further compromise the system.\u003c/li\u003e\n\u003cli\u003eAttacker achieves persistence and performs lateral movement, exfiltrating data or deploying ransomware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to the disabling of critical security services, such as antivirus, endpoint detection and response (EDR) agents, or other monitoring tools. This can significantly reduce the visibility of malicious activity within the network, potentially leading to data breaches, ransomware deployment, or other severe security incidents. The SolarWinds supply chain compromise affected numerous organizations globally, underscoring the potential impact of this type of attack.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSolarWinds Process Disabling Services via Registry\u003c/code\u003e to your SIEM to detect registry modifications by SolarWinds processes aimed at disabling services.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to provide the necessary data for the Sigma rule to function effectively.\u003c/li\u003e\n\u003cli\u003eReview and harden access controls for SolarWinds processes to restrict their ability to modify critical system settings.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the affected service and the timeline of events surrounding the registry modification.\u003c/li\u003e\n\u003cli\u003eUtilize threat intelligence platforms to stay informed about known SolarWinds-related attack patterns and indicators of compromise (IOCs).\u003c/li\u003e\n\u003cli\u003eMonitor endpoints for unusual behavior by SolarWinds processes, including network connections, file modifications, and process creations.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-solarwinds-service-disable/","summary":"A SolarWinds binary is modifying the start type of a service to be disabled via registry modification, potentially to disable or impair security services.","title":"SolarWinds Process Disabling Services via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-solarwinds-service-disable/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows Work Folders","Microsoft Defender XDR","SentinelOne Cloud Funnel","CrowdStrike"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","masquerading","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eWindows Work Folders is a Microsoft file server role that allows users to sync work files between their PCs and a central server. The WorkFolders.exe process, when called, will automatically execute any Portable Executable (PE) named control.exe as an argument before accessing the synced share. Attackers can abuse this functionality by placing a malicious executable renamed to control.exe in a location synced by Work Folders, and then triggering WorkFolders.exe. This can lead to the execution of arbitrary code in a manner that bypasses application control policies, as WorkFolders.exe is a signed Microsoft binary. This technique has been observed in the wild and documented by security researchers. This allows attackers to execute code from locations outside the standard Windows directories, evading traditional detection mechanisms.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the target system through an unspecified means (e.g., phishing, exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker places a malicious executable and renames it to \u003ccode\u003econtrol.exe\u003c/code\u003e in a directory accessible to Work Folders.\u003c/li\u003e\n\u003cli\u003eThe attacker configures Windows Work Folders to synchronize the directory containing the malicious \u003ccode\u003econtrol.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe victim system synchronizes with the Work Folders server, copying the malicious \u003ccode\u003econtrol.exe\u003c/code\u003e to the local machine.\u003c/li\u003e\n\u003cli\u003eThe attacker triggers the \u003ccode\u003eWorkFolders.exe\u003c/code\u003e process.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003eWorkFolders.exe\u003c/code\u003e executes the \u003ccode\u003econtrol.exe\u003c/code\u003e binary from the synced folder.\u003c/li\u003e\n\u003cli\u003eThe malicious \u003ccode\u003econtrol.exe\u003c/code\u003e executes, performing attacker-defined actions such as establishing persistence, escalating privileges, or deploying additional malware.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves code execution in a potentially elevated context, leveraging a signed Microsoft binary (\u003ccode\u003eWorkFolders.exe\u003c/code\u003e) to bypass security controls.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to execute arbitrary code on a victim\u0026rsquo;s machine, potentially bypassing application control and other security measures. This can lead to a range of malicious activities, including data theft, system compromise, and lateral movement within the network. Given the legitimate use of Work Folders, identifying malicious executions can be challenging, potentially allowing attackers to maintain a persistent foothold. The lack of specific victim counts or industry targeting details in the source material limits a complete assessment of impact scope.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor process creations where \u003ccode\u003eWorkFolders.exe\u003c/code\u003e is the parent process and \u003ccode\u003econtrol.exe\u003c/code\u003e is the child process, but \u003ccode\u003econtrol.exe\u003c/code\u003e is not located in a standard Windows system directory (Sigma rule: \u0026ldquo;Detect Suspicious WorkFolders Control Execution\u0026rdquo;).\u003c/li\u003e\n\u003cli\u003eInvestigate any instances where \u003ccode\u003econtrol.exe\u003c/code\u003e is executed from unusual or user-writable locations, especially if \u003ccode\u003eWorkFolders.exe\u003c/code\u003e is involved (see Attack Chain step 6).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) on Windows systems to capture the necessary data for the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eReview the Microsoft documentation on Windows Information Protection (WIP) and consider implementing it to encrypt data on PCs using Work Folders.\u003c/li\u003e\n\u003cli\u003eImplement application control policies that restrict the execution of \u003ccode\u003econtrol.exe\u003c/code\u003e to authorized locations (e.g., \u003ccode\u003eC:\\Windows\\System32\u003c/code\u003e).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-03-workfolders-control-execution/","summary":"Attackers can abuse Windows Work Folders to execute a masqueraded control.exe file from untrusted locations, potentially bypassing application controls for defense evasion and privilege escalation.","title":"Signed Proxy Execution via MS Work Folders","url":"https://feed.craftedsignal.io/briefs/2024-01-03-workfolders-control-execution/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","masquerading","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies the execution of a process with a single-character process name that differs from the original file name. Adversaries often employ this technique during staging, to execute temporary utilities, or to bypass security detections relying on process names. This behavior is typically observed in Windows environments where attackers attempt to masquerade their activities by renaming legitimate utilities to short, less conspicuous names, making it harder to identify malicious processes based on their name alone. The detection leverages process creation events from Elastic Defend, Microsoft Defender XDR, Crowdstrike, and Sysmon to identify such anomalies. The rule was initially created on 2020-11-15 and last updated on 2026-05-04.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through various means (e.g., phishing, exploitation of vulnerabilities).\u003c/li\u003e\n\u003cli\u003eThe attacker renames a legitimate utility (e.g., \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e) to a single-character name such as \u003ccode\u003ea.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe renamed utility \u003ccode\u003ea.exe\u003c/code\u003e is executed, potentially without parameters initially, to test execution.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the renamed utility \u003ccode\u003ea.exe\u003c/code\u003e to execute commands, download additional payloads, or perform reconnaissance.\u003c/li\u003e\n\u003cli\u003eThe commands executed by \u003ccode\u003ea.exe\u003c/code\u003e might involve further obfuscation techniques to evade detection, such as base64 encoding or encryption.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the renamed utility to establish persistence by creating scheduled tasks or modifying registry keys.\u003c/li\u003e\n\u003cli\u003eThe attacker moves laterally within the network, using the compromised host as a staging point.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data exfiltration or ransomware deployment.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack using this technique can lead to significant compromise of the target system. By renaming legitimate utilities, attackers can bypass standard security measures that rely on process names for detection. This can result in delayed detection, allowing the attacker to perform further malicious activities such as data theft, installation of malware, or lateral movement within the network. While specific numbers are unavailable, this technique has been observed across various organizations, making it a relevant threat for defenders.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable process creation logging via Sysmon or Elastic Defend to provide the necessary data for detection.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Suspicious Renamed Utility Execution\u0026rdquo; to your SIEM and tune it based on your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by examining the parent process and command-line arguments.\u003c/li\u003e\n\u003cli\u003eReview the osquery queries in the brief for additional context gathering during incident response.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-renamed-utility-short-name/","summary":"This rule detects the execution of renamed utilities with a single-character process name, differing from the original filename, a common technique used by adversaries for staging, executing temporary utilities, or bypassing security detections.","title":"Renamed Utility Executed with Short Program Name","url":"https://feed.craftedsignal.io/briefs/2024-01-renamed-utility-short-name/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR"],"_cs_severities":["medium"],"_cs_tags":["command and control","rmm","msi","windows","remote access"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eThis detection identifies a suspicious sequence of events where an MSI installer is executed, followed by the launch of remote management software (RMM) such as ScreenConnect, Syncro, or VNC. Attackers may leverage this technique to gain unauthorized access to systems by first installing malicious software via an MSI package, and then using the RMM software to establish a remote connection. The rule specifically looks for msiexec.exe being run with an install argument (/i) followed by the execution of known RMM tools within a short timeframe. This behavior is often indicative of malicious actors attempting to establish persistent remote access to compromised machines. The detection is designed for Windows environments and covers a range of data sources including Elastic Defend, Sysmon, SentinelOne, Microsoft Defender XDR, and Crowdstrike.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system through various means (e.g., social engineering, compromised website, or existing malware).\u003c/li\u003e\n\u003cli\u003eThe attacker deploys a malicious MSI installer to the victim machine. This can be done through phishing attachments or drive-by downloads.\u003c/li\u003e\n\u003cli\u003eThe user executes the MSI installer (msiexec.exe) with an installation argument (/i or -i). The parent process is typically explorer.exe or sihost.exe, indicating user-initiated installation.\u003c/li\u003e\n\u003cli\u003eThe MSI installer executes, potentially installing malware or modifying system settings.\u003c/li\u003e\n\u003cli\u003eWithin one minute of the MSI installation, a remote management software (RMM) client is launched, such as ScreenConnect.ClientService.exe, Syncro.Installer.exe, tvnserver.exe, or winvnc.exe.\u003c/li\u003e\n\u003cli\u003eThe RMM client attempts to establish an outbound connection to a remote server controlled by the attacker, often using pre-configured access keys.\u003c/li\u003e\n\u003cli\u003eThe attacker gains remote access to the compromised system via the RMM client. In the case of ScreenConnect, the attacker may use a guest link with a known session key.\u003c/li\u003e\n\u003cli\u003eThe attacker performs malicious activities, such as data exfiltration, lateral movement, or installing additional malware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to gain persistent remote access to compromised systems. This can lead to data theft, financial fraud, or disruption of services. Depending on the scope of the initial access, the attacker may be able to move laterally within the network, compromising additional systems. The use of RMM software can mask malicious activity as legitimate remote support, making detection more difficult.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable process creation logging via Sysmon or Windows Security Event Logs to capture the execution of msiexec.exe and RMM tools.\u003c/li\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Remote Management Access Launch After MSI Install\u0026rdquo; Sigma rule to your SIEM and tune the timeframe (maxspan) to suit your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by this rule, focusing on the source of the MSI file and the destination of the RMM connection.\u003c/li\u003e\n\u003cli\u003eBlock the execution of unauthorized RMM software on your network based on process name, as identified in the rule (ScreenConnect.ClientService.exe, Syncro.Installer.exe, tvnserver.exe, winvnc.exe).\u003c/li\u003e\n\u003cli\u003eMonitor network connections for RMM software connecting to unusual or external IPs.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-rmm-after-msi/","summary":"Detects an MSI installer execution followed by the execution of commonly abused Remote Management Software like ScreenConnect, potentially indicating abuse where an attacker triggers an MSI install then connects via a guest link with a known session key.","title":"Remote Management Access Launch After MSI Install","url":"https://feed.craftedsignal.io/briefs/2024-01-rmm-after-msi/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["command-and-control","file-download","windows","desktopimgdownldr"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThe \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e utility, a legitimate Windows tool for configuring lock screen and desktop images, can be misused by adversaries to download arbitrary files from remote locations. This is achieved by leveraging the \u003ccode\u003e/lockscreenurl\u003c/code\u003e argument followed by an HTTP or HTTPS URL. This technique allows attackers to bypass traditional download restrictions and can be used to retrieve malicious payloads, tools, or scripts directly onto a compromised system. This method is particularly effective because \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e is a signed Microsoft binary, potentially evading initial detection based on process name or file reputation. The detection rule was initially created in September 2020 and updated in May 2026. This technique is valuable for attackers seeking to transfer files without using common tools like \u003ccode\u003ecertutil\u003c/code\u003e, \u003ccode\u003epowershell\u003c/code\u003e, or \u003ccode\u003ebitsadmin\u003c/code\u003e.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the target system through an existing vulnerability, credential compromise, or social engineering.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e with the \u003ccode\u003e/lockscreenurl\u003c/code\u003e argument, specifying a URL from which to download a malicious file.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e initiates an HTTP or HTTPS request to the specified URL.\u003c/li\u003e\n\u003cli\u003eThe remote server responds with the file content, which \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e saves to disk.\u003c/li\u003e\n\u003cli\u003eThe attacker then executes the downloaded file (e.g., a malicious script or executable).\u003c/li\u003e\n\u003cli\u003eThe malicious code performs actions such as establishing persistence, escalating privileges, or deploying further malware.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the compromised system to move laterally within the network, accessing sensitive data and systems.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data exfiltration, ransomware deployment, or disruption of services.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to download and execute arbitrary files on a Windows system, leading to potential compromise of the host and the network. This can result in data theft, system damage, or ransomware infection. Due to the legitimate nature of the \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e utility, this technique can bypass security controls and detection mechanisms, increasing the likelihood of successful exploitation. While the exact number of victims is unknown, any Windows system where an attacker can execute commands is potentially vulnerable.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Remote File Download via Desktopimgdownldr Utility\u0026rdquo; to your SIEM to detect the execution of \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e with the \u003ccode\u003e/lockscreenurl\u003c/code\u003e argument.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e to identify suspicious command-line arguments.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to ensure sufficient data is available for the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of \u003ccode\u003edesktopimgdownldr.exe\u003c/code\u003e downloading files from external URLs to determine if they are malicious.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of unauthorized or unknown executables in sensitive environments.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-desktopimgdownldr-remote-file-copy/","summary":"The desktopimgdownldr utility can be abused to download remote files, potentially bypassing standard download restrictions and acting as an alternative to certutil for malware or tool deployment.","title":"Remote File Download via Desktopimgdownldr Utility","url":"https://feed.craftedsignal.io/briefs/2024-01-desktopimgdownldr-remote-file-copy/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["lateral-movement","data-staging","windows","hidden-share"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection rule identifies attempts to copy files to hidden network shares in Windows environments, which can be indicative of lateral movement or data staging by malicious actors. Attackers may leverage hidden shares, typically used for legitimate administrative purposes, to move laterally within a network or to stage data for exfiltration without being easily detected. The rule focuses on detecting the use of command-line tools such as cmd.exe and powershell.exe with arguments that specify the copying of files to network paths that match a hidden share pattern (e.g., \u003ccode\u003e\\\\\\\\*\\\\\\\\*$\u003c/code\u003e). This activity helps identify suspicious file transfer operations that deviate from normal administrative or user behavior. The rule was last updated on 2026/05/04.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a compromised host within the network.\u003c/li\u003e\n\u003cli\u003eThe attacker uses cmd.exe or powershell.exe to execute a file copy command.\u003c/li\u003e\n\u003cli\u003eThe command line includes arguments to copy files to a hidden network share (e.g., \u003ccode\u003e\\\\\\\\\u0026lt;server\u0026gt;\\\\\u0026lt;hidden_share\u0026gt;$\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003ecopy\u003c/code\u003e, \u003ccode\u003emove\u003c/code\u003e, \u003ccode\u003ecp\u003c/code\u003e, or \u003ccode\u003emv\u003c/code\u003e commands are used to transfer the file.\u003c/li\u003e\n\u003cli\u003eThe target hidden share is accessed using the compromised account\u0026rsquo;s credentials.\u003c/li\u003e\n\u003cli\u003eThe file is successfully copied to the hidden share.\u003c/li\u003e\n\u003cli\u003eThe attacker may then access the copied file from another compromised host.\u003c/li\u003e\n\u003cli\u003eThe attacker proceeds to exfiltrate the staged data or uses the copied files for lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to unauthorized access to sensitive data, lateral movement to other systems within the network, and potential data exfiltration. While the number of victims and specific sectors targeted are not specified, a successful compromise can significantly impact an organization\u0026rsquo;s data security and overall network integrity. The impact includes potential data loss, reputational damage, and disruption of normal business operations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Detect Remote File Copy to Hidden Share\u0026rdquo; Sigma rule to your SIEM and tune for your environment to detect suspicious file copy activities.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process-creation logging to capture the command-line arguments used in file copy operations, activating the rule above.\u003c/li\u003e\n\u003cli\u003eReview and restrict permissions on network shares, especially hidden shares, to ensure only authorized users have access, as described in the investigation guide.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by examining the process details (cmd.exe, powershell.exe) and the network share path, as outlined in the investigation guide.\u003c/li\u003e\n\u003cli\u003eCorrelate events with other logs or alerts from the same host or user to identify any additional suspicious activities, enhancing the detection capabilities.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-03-remote-file-copy-hidden-share/","summary":"This rule detects remote file copy attempts to hidden network shares, which may indicate lateral movement or data staging activity, by identifying suspicious file copy operations using command-line tools like cmd.exe and powershell.exe focused on hidden share patterns.","title":"Remote File Copy to a Hidden Share","url":"https://feed.craftedsignal.io/briefs/2024-01-03-remote-file-copy-hidden-share/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Windows","Microsoft Defender XDR","Commvault","Nvidia Display Driver","Elastic Defend","SentinelOne Cloud Funnel","CrowdStrike FDR"],"_cs_severities":["medium"],"_cs_tags":["persistence","defense-evasion","appinit-dlls","registry","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Commvault","Nvidia","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThe AppInit DLLs mechanism allows dynamic-link libraries (DLLs) to be loaded into every process that creates a user interface (loads user32.dll) on Microsoft Windows operating systems. This mechanism is intended for customization of the user interface and behavior of Windows-based applications. However, attackers can abuse this by adding malicious DLLs to the registry locations associated with AppInit DLLs. This enables them to execute code with elevated privileges, similar to process injection, and maintain a persistent presence on the compromised machine. This technique is often used to maintain access after initial compromise. Detection focuses on registry modifications to the relevant keys, excluding known legitimate processes to minimize false positives. The referenced Elastic rule was last updated on 2026/05/04.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system through a vulnerability, phishing, or other means.\u003c/li\u003e\n\u003cli\u003eThe attacker identifies the AppInit DLLs registry keys: \u003ccode\u003eHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Windows\u003c/code\u003e or \u003ccode\u003eHKEY_LOCAL_MACHINE\\SOFTWARE\\Wow6432Node\\Microsoft\\Windows NT\\CurrentVersion\\Windows\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the \u003ccode\u003eAppInit_DLLs\u003c/code\u003e registry value to include the path to their malicious DLL.\u003c/li\u003e\n\u003cli\u003eThe attacker\u0026rsquo;s DLL is placed on the filesystem, typically in a location where it will persist across reboots.\u003c/li\u003e\n\u003cli\u003eAny new process that loads user32.dll will automatically load the attacker\u0026rsquo;s malicious DLL.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL executes arbitrary code within the context of the newly created process.\u003c/li\u003e\n\u003cli\u003eThe attacker can use this code execution to perform further actions, such as installing backdoors or escalating privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistent access to the system through the malicious DLL loaded into every user interface process.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to execute arbitrary code within the context of any process that loads \u003ccode\u003euser32.dll\u003c/code\u003e. This provides a persistent mechanism for maintaining access to the compromised system. The attacker gains code execution with elevated privileges, similar to process injection. This can lead to data theft, system compromise, or further lateral movement within the network. While no specific victim counts are mentioned, the widespread use of Windows makes this a potentially high-impact vulnerability.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor registry modifications to the \u003ccode\u003eAppInit_DLLs\u003c/code\u003e value in \u003ccode\u003eHKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Windows\u003c/code\u003e and \u003ccode\u003eHKEY_LOCAL_MACHINE\\SOFTWARE\\Wow6432Node\\Microsoft\\Windows NT\\CurrentVersion\\Windows\u003c/code\u003e using the \u0026ldquo;Registry Persistence via AppInit DLL Modification\u0026rdquo; Sigma rule.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to provide the data required for the Sigma rule to function correctly.\u003c/li\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Registry Persistence via AppInit DLL Modification\u0026rdquo; Sigma rule to your SIEM and tune the filter to exclude known-good DLL paths in your environment.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rule, focusing on the parent process and the DLL being loaded.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-appinit-dll-persistence/","summary":"Modification of the AppInit DLLs registry keys on Windows systems allows attackers to execute code in every process that loads user32.dll, establishing persistence and potentially escalating privileges.","title":"Registry Persistence via AppInit DLL Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-appinit-dll-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Crowdstrike"],"_cs_severities":["medium"],"_cs_tags":["persistence","privilege-escalation","appcert-dll"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThe rule detects attempts to maintain persistence by creating or modifying registry keys associated with AppCert DLLs on Windows systems. AppCert DLLs are loaded by every process that uses common API functions to create processes, making them a viable target for persistence. Adversaries can exploit this by inserting malicious DLL paths into the registry, ensuring their code executes persistently across system reboots. This technique is often used for privilege escalation and persistence. The rule specifically looks for changes in the registry path \u003ccode\u003eHKLM\\SYSTEM\\ControlSet*\\Control\\Session Manager\\AppCertDLLs\\*\u003c/code\u003e, as well as the equivalent \u003ccode\u003e\\\\REGISTRY\\\\MACHINE\\\\SYSTEM\\...\u003c/code\u003e path. This activity matters because it can lead to stealthy and persistent malware infections. The rule is designed for use with data from Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, Crowdstrike, and Sysmon. The detection logic was last updated on 2026/05/04.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system (e.g., through phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker obtains necessary privileges to modify the Windows Registry, potentially requiring administrator rights.\u003c/li\u003e\n\u003cli\u003eThe attacker creates or modifies a registry key under \u003ccode\u003eHKLM\\SYSTEM\\ControlSet*\\Control\\Session Manager\\AppCertDLLs\\*\u003c/code\u003e to point to a malicious DLL.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL is placed on the file system, often in a location that appears legitimate or is easily accessible.\u003c/li\u003e\n\u003cli\u003eAny process that uses the standard Windows API to create new processes will load the specified DLL.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL executes its payload, which could include establishing persistence, injecting into other processes, or performing other malicious activities.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence by ensuring the malicious DLL is loaded every time a new process is created.\u003c/li\u003e\n\u003cli\u003eThe final objective is to maintain long-term access to the compromised system, potentially escalating privileges and moving laterally within the network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to achieve persistent code execution on the system. This can lead to complete system compromise, data theft, or further propagation of malware within the network. The use of AppCert DLLs allows the malicious code to run in the context of nearly every process, making detection and removal more challenging. Without proper detection and response mechanisms, an attacker can maintain control of the system indefinitely.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon registry event logging and configure it to monitor the relevant AppCertDLLs registry paths to capture the necessary events for the rules (Data Source: Sysmon).\u003c/li\u003e\n\u003cli\u003eDeploy the provided Sigma rule \u003ccode\u003eDetect AppCert DLL Registry Modification\u003c/code\u003e to your SIEM to detect unauthorized modifications to the AppCertDLLs registry keys (Rule: Detect AppCert DLL Registry Modification).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the rule \u003ccode\u003eDetect AppCert DLL Registry Modification\u003c/code\u003e to determine the legitimacy of the registry modifications, using the provided triage steps as a guide.\u003c/li\u003e\n\u003cli\u003eRegularly scan systems for malicious DLLs located in the file system using updated antivirus and anti-malware tools, focusing on DLLs referenced in the AppCertDLLs registry keys.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-appcert-dll-persistence/","summary":"Detection of registry modifications related to AppCert DLLs, a persistence mechanism where malicious DLLs are loaded by every process using common API functions.","title":"Registry Persistence via AppCert DLL Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-appcert-dll-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["lateral-movement","defense-evasion","rdp","registry-modification"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers may enable Remote Desktop Protocol (RDP) to facilitate lateral movement within a compromised network. By modifying the \u003ccode\u003efDenyTSConnections\u003c/code\u003e registry key to a value of \u003ccode\u003e0\u003c/code\u003e, attackers can enable remote desktop connections, allowing them to access systems remotely. This technique can be employed using remote registry manipulation or tools like PsExec. The modification of the registry key is a common tactic used by ransomware operators and other threat actors to gain unauthorized access to victim servers. This activity can be performed to enable remote access for initial access or to regain access after persistence mechanisms have failed.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system via an exploit or compromised credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a tool like PsExec or leverages remote registry modification capabilities.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the \u003ccode\u003efDenyTSConnections\u003c/code\u003e registry key, setting its value to \u003ccode\u003e0\u003c/code\u003e. This key is typically located in \u003ccode\u003eHKLM\\SYSTEM\\CurrentControlSet\\Control\\Terminal Server\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe system\u0026rsquo;s RDP service is enabled or re-enabled as a result of the registry change.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to connect to the now-enabled RDP service using valid or brute-forced credentials.\u003c/li\u003e\n\u003cli\u003eUpon successful authentication, the attacker gains interactive access to the system via RDP.\u003c/li\u003e\n\u003cli\u003eThe attacker performs reconnaissance, elevates privileges, and moves laterally to other systems.\u003c/li\u003e\n\u003cli\u003eThe attacker deploys ransomware, exfiltrates data, or achieves other objectives.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of the \u003ccode\u003efDenyTSConnections\u003c/code\u003e registry key allows unauthorized remote access to systems, potentially leading to lateral movement, data theft, or ransomware deployment. Organizations could suffer significant financial losses, reputational damage, and operational disruption. The scope of the impact depends on the attacker\u0026rsquo;s objectives and the level of access they gain within the environment.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;RDP Enabled via Registry\u0026rdquo; to detect modifications to the \u003ccode\u003efDenyTSConnections\u003c/code\u003e registry key (rules).\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for suspicious use of \u003ccode\u003ereg.exe\u003c/code\u003e or PowerShell to modify registry keys related to RDP (rules).\u003c/li\u003e\n\u003cli\u003eImplement network segmentation and firewall rules to restrict RDP traffic to authorized hosts (overview).\u003c/li\u003e\n\u003cli\u003eReview the privileges assigned to users and ensure the principle of least privilege is enforced (overview).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to capture registry modifications (setup).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts related to registry modifications on critical systems (overview).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-rdp-registry-enabled/","summary":"An adversary may enable Remote Desktop Protocol (RDP) access by modifying the `fDenyTSConnections` registry key, potentially indicating lateral movement preparation or defense evasion.","title":"RDP Enabled via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-rdp-registry-enabled/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend","CrowdStrike"],"_cs_severities":["medium"],"_cs_tags":["credential-access","webdav","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike"],"content_html":"\u003cp\u003eAttackers can exploit WebDAV by injecting WebDAV paths into files or features opened by a victim user, leading to NTLM credential leakage through forced authentication. This technique relies on the victim\u0026rsquo;s system attempting to authenticate against a malicious WebDAV server when accessing a file or link containing a WebDAV path. This threat is particularly relevant for defenders because it can lead to unauthorized access to sensitive information and potential lateral movement within the network. The attack leverages \u003ccode\u003erundll32.exe\u003c/code\u003e to initiate the WebDAV connection, making it difficult to distinguish from legitimate system processes. The Elastic detection rule identifies rare WebDAV connection attempts to uncover potential credential access attempts.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker crafts a malicious document or link containing a WebDAV path.\u003c/li\u003e\n\u003cli\u003eThe victim user opens the malicious document or clicks the link.\u003c/li\u003e\n\u003cli\u003eThe operating system attempts to resolve the WebDAV path using \u003ccode\u003erundll32.exe\u003c/code\u003e and the \u003ccode\u003eDavSetCookie\u003c/code\u003e function.\u003c/li\u003e\n\u003cli\u003eThe system initiates an authentication attempt with the malicious WebDAV server.\u003c/li\u003e\n\u003cli\u003eThe attacker captures the NTLM credentials during the authentication handshake.\u003c/li\u003e\n\u003cli\u003eThe attacker relays the captured NTLM credentials to access internal resources.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation leads to credential compromise and potential lateral movement within the victim\u0026rsquo;s network. An attacker could gain unauthorized access to sensitive data and systems, potentially leading to data exfiltration, system compromise, or further attacks. This can impact organizations of any size and industry that rely on NTLM authentication. The severity depends on the user\u0026rsquo;s permissions and the resources they can access with their compromised credentials.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rule to your SIEM and tune for your environment to detect suspicious WebDAV connections initiated via \u003ccode\u003erundll32.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on rare or unusual WebDAV destinations.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for \u003ccode\u003erundll32.exe\u003c/code\u003e with command-line arguments containing \u0026ldquo;DavSetCookie\u0026rdquo;, focusing on connections to external domains.\u003c/li\u003e\n\u003cli\u003eConduct regular security awareness training to educate users about the risks of opening unsolicited documents or clicking suspicious links.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-rare-webdav/","summary":"This rule identifies rare connection attempts to a Web Distributed Authoring and Versioning (WebDAV) resource, where attackers may inject WebDAV paths in files opened by a victim to leak NTLM credentials via forced authentication using rundll32.exe.","title":"Rare Connection to WebDAV Target via Rundll32","url":"https://feed.craftedsignal.io/briefs/2024-01-rare-webdav/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["privilege-escalation","persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eAdversaries can exploit the Local Security Authority (LSA) authentication packages in Windows to escalate privileges or establish persistence. This involves modifying specific registry paths to include references to malicious binaries. When the authentication packages are loaded, these binaries are executed with SYSTEM privileges, effectively granting the attacker elevated access. The Elastic detection rule identifies unauthorized registry changes to LSA authentication packages by non-SYSTEM users, signaling potential malicious activity. This technique can be used for long-term persistence or immediate privilege escalation, allowing attackers to perform unauthorized actions on the compromised system. The rule leverages data from Elastic Defend and Microsoft Defender XDR to detect these unauthorized modifications.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system through unspecified means.\u003c/li\u003e\n\u003cli\u003eThe attacker identifies the \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\Authentication Packages\u003c/code\u003e registry key as a target for persistence and privilege escalation.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the registry key to include a path to a malicious binary. This binary will be loaded as an authentication package.\u003c/li\u003e\n\u003cli\u003eThe operating system loads the LSA authentication packages during system startup or user logon.\u003c/li\u003e\n\u003cli\u003eThe malicious binary, now executed with SYSTEM privileges, performs actions dictated by the attacker.\u003c/li\u003e\n\u003cli\u003eThis could involve creating new user accounts with administrative privileges, installing backdoors, or disabling security controls.\u003c/li\u003e\n\u003cli\u003eThe attacker establishes persistence, ensuring that the malicious binary is executed every time the system starts or a user logs on.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of LSA authentication packages allows an attacker to gain SYSTEM-level privileges on the compromised system. This can lead to complete system compromise, data theft, and the installation of persistent backdoors. The rule aims to detect unauthorized changes to these packages, preventing attackers from establishing persistence and escalating privileges.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the provided Sigma rules to your SIEM and tune for your environment to detect unauthorized changes to the LSA authentication packages.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rules, focusing on registry changes made by non-SYSTEM users to the \u003ccode\u003eHKLM\\SYSTEM\\*\\ControlSet*\\Control\\Lsa\\Authentication Packages\u003c/code\u003e registry key.\u003c/li\u003e\n\u003cli\u003eEnable registry auditing to capture changes to sensitive registry keys, including the LSA authentication packages path, to improve detection capabilities.\u003c/li\u003e\n\u003cli\u003eUtilize Elastic Defend and Microsoft Defender XDR for endpoint detection and response, as these data sources are specifically supported by the detection rule.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-lsa-auth-package-abuse/","summary":"Adversaries can abuse the Local Security Authority (LSA) authentication packages by modifying the Windows registry to achieve privilege escalation or persistence by executing binaries with SYSTEM privileges.","title":"Potential LSA Authentication Package Abuse","url":"https://feed.craftedsignal.io/briefs/2024-01-lsa-auth-package-abuse/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["high"],"_cs_tags":["credential-access","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Cisco Systems","Microsoft","SentinelOne"],"content_html":"\u003cp\u003eThis rule identifies the execution of Windows utilities commonly abused to dump LSASS memory or the Active Directory database (NTDS.dit) in preparation for credential access. Attackers often leverage these tools to extract sensitive information, such as user credentials and domain secrets. The utilities of interest include procdump, ProcessDump.exe, WriteMiniDump.exe, RUNDLL32.EXE, RdrLeakDiag.exe, SqlDumper.exe, TTTracer.exe, ntdsutil.exe, and diskshadow.exe. The rule focuses on detecting specific command-line arguments and process names indicative of credential dumping activities. This activity is typically associated with post-exploitation phases, where attackers aim to escalate privileges and move laterally within a network. This detection is crucial for defenders as it can reveal ongoing credential theft attempts, allowing for prompt intervention and mitigation.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to a Windows system through various means, such as phishing, exploiting vulnerabilities, or using compromised credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker executes a privileged process, such as \u003ccode\u003ecmd.exe\u003c/code\u003e or \u003ccode\u003epowershell.exe\u003c/code\u003e, to perform reconnaissance and identify potential targets for credential dumping.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a utility like \u003ccode\u003eprocdump.exe\u003c/code\u003e with the \u003ccode\u003e-ma\u003c/code\u003e flag to dump the LSASS process memory (\u003ccode\u003eprocdump.exe -ma lsass.exe\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eAlternatively, the attacker uses \u003ccode\u003entdsutil.exe\u003c/code\u003e to create an IFM (Install From Media) snapshot of the Active Directory database (\u003ccode\u003entdsutil.exe \u0026quot;ac i ntds\u0026quot; \u0026quot;ifm\u0026quot; \u0026quot;cr fu c:\\\\temp\u0026quot; q q\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe attacker may use \u003ccode\u003ediskshadow.exe\u003c/code\u003e with a script (\u003ccode\u003e/s\u003c/code\u003e) to create shadow copies of the system volume, potentially including the NTDS.dit file.\u003c/li\u003e\n\u003cli\u003eThe attacker stages the dumped credentials or database files in a temporary directory.\u003c/li\u003e\n\u003cli\u003eThe attacker compresses the staged data using archiving tools for easier transfer.\u003c/li\u003e\n\u003cli\u003eFinally, the attacker exfiltrates the compressed data to an external server for further analysis and credential harvesting.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to widespread credential compromise, allowing attackers to gain unauthorized access to sensitive systems and data. Credential theft can enable lateral movement within the network, privilege escalation, and ultimately, data exfiltration or ransomware deployment. The targeted dumping of LSASS memory exposes user credentials, while the extraction of the Active Directory database can compromise the entire domain. The severity of the impact depends on the scope of the compromise and the sensitivity of the affected data.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rules provided in this brief to your SIEM to detect suspicious process execution patterns indicative of credential dumping (Sigma rule: \u0026ldquo;Potential Credential Access via Procdump\u0026rdquo;).\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for the execution of known credential dumping utilities with suspicious command-line arguments using the provided Sigma rules, enabling process creation logging via Sysmon (Sigma rule: \u0026ldquo;Potential Credential Access via NTDSUtil\u0026rdquo;).\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of unauthorized or untrusted binaries, especially those associated with credential dumping, referencing the list of tools described in the Overview.\u003c/li\u003e\n\u003cli\u003eReview and harden Active Directory security configurations to prevent unauthorized access to the NTDS.dit file, using Microsoft\u0026rsquo;s security guidance.\u003c/li\u003e\n\u003cli\u003eRegularly audit and monitor systems for suspicious file creation and modification events, particularly those involving potential credential dumps, and ensure proper file integrity monitoring is enabled.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-potential-credential-access-windows-utilities/","summary":"This rule detects the execution of known Windows utilities often abused to dump LSASS memory or the Active Directory database (NTDS.dit) in preparation for credential access by identifying specific command-line arguments and process names associated with credential dumping activities.","title":"Potential Credential Access via Windows Utilities","url":"https://feed.craftedsignal.io/briefs/2024-01-potential-credential-access-windows-utilities/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Sysmon","Elastic Defend","Elastic Endpoint Security","CrowdStrike Falcon","SentinelOne Cloud Funnel","Windows Security Event Logs","winlogbeat"],"_cs_severities":["medium"],"_cs_tags":["persistence","execution","windows","wmi"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne","Elastic"],"content_html":"\u003cp\u003eWindows Management Instrumentation (WMI) provides a powerful framework for managing Windows systems, but adversaries can abuse its capabilities to establish persistence. By creating WMI event subscriptions, attackers can execute arbitrary code in response to defined system events. This technique involves creating event filters, providers, consumers, and bindings that automatically run malicious code. This can be achieved through tools like \u003ccode\u003ewmic.exe\u003c/code\u003e, which allows the creation of event consumers such as \u003ccode\u003eActiveScriptEventConsumer\u003c/code\u003e or \u003ccode\u003eCommandLineEventConsumer\u003c/code\u003e. Successful exploitation of WMI for persistence allows attackers to maintain unauthorized access to a compromised system, even after reboots or other system changes. This activity has been observed across various environments, highlighting the need for robust detection mechanisms to identify and prevent WMI-based persistence.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system through unspecified means.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003ewmic.exe\u003c/code\u003e to create a WMI event filter that defines a specific event to monitor.\u003c/li\u003e\n\u003cli\u003eA WMI event consumer, such as \u003ccode\u003eActiveScriptEventConsumer\u003c/code\u003e or \u003ccode\u003eCommandLineEventConsumer\u003c/code\u003e, is created using \u003ccode\u003ewmic.exe\u003c/code\u003e specifying the malicious code or script to execute when the event occurs.\u003c/li\u003e\n\u003cli\u003eA WMI binding is established between the event filter and the event consumer using \u003ccode\u003ewmic.exe\u003c/code\u003e, linking the event to the action.\u003c/li\u003e\n\u003cli\u003eThe malicious WMI event subscription is activated, monitoring for the defined event.\u003c/li\u003e\n\u003cli\u003eWhen the specified event occurs, the WMI service triggers the execution of the associated malicious code or script through the event consumer.\u003c/li\u003e\n\u003cli\u003eThe attacker gains persistent access to the system, as the WMI event subscription will re-activate after reboots.\u003c/li\u003e\n\u003cli\u003eThe attacker can then perform additional malicious activities, such as lateral movement or data exfiltration.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of WMI for persistence can allow an attacker to maintain long-term, unauthorized access to a compromised system. This can result in data theft, system compromise, and further malicious activities. While the exact number of victims is not specified in the source, the broad applicability of this technique means that many Windows systems are potentially at risk. If the attack succeeds, the attacker gains a foothold on the system that is difficult to detect and remove, which can lead to significant operational disruption and financial loss.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable process creation logging and monitor for \u003ccode\u003ewmic.exe\u003c/code\u003e with command-line arguments related to creating event consumers, specifically \u003ccode\u003eActiveScriptEventConsumer\u003c/code\u003e or \u003ccode\u003eCommandLineEventConsumer\u003c/code\u003e, to trigger the Sigma rule \u0026ldquo;Detect Suspicious WMIC Process\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eDeploy the provided Sigma rule to your SIEM to detect suspicious WMI event subscription creation.\u003c/li\u003e\n\u003cli\u003eReview the investigation steps outlined in the provided documentation to triage and analyze potential WMI persistence attempts.\u003c/li\u003e\n\u003cli\u003eMonitor Windows Security Event Logs and Sysmon for events related to WMI activity for broader coverage.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-wmi-persistence/","summary":"Adversaries can leverage Windows Management Instrumentation (WMI) to establish persistence by creating event subscriptions that trigger malicious code execution when specific events occur, using tools like wmic.exe to create event consumers.","title":"Persistence via WMI Event Subscription","url":"https://feed.craftedsignal.io/briefs/2024-01-wmi-persistence/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Exchange Server","Elastic Defend","CrowdStrike","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["exchange","activesync","powershell","persistence"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne","Elastic"],"content_html":"\u003cp\u003eThis detection identifies the use of the Exchange PowerShell cmdlet, \u003ccode\u003eSet-CASMailbox\u003c/code\u003e, to add a new ActiveSync allowed device. Attackers may target user email to collect sensitive information by adding unauthorized devices to a user\u0026rsquo;s allowed ActiveSync devices. The rule focuses on detecting suspicious PowerShell activity by monitoring for specific command patterns indicative of unauthorized device additions. This activity can lead to persistent access to sensitive email data, bypassing normal authentication controls. The original Elastic detection rule was created on 2020/12/15 and updated on 2026/05/04. This matters for defenders because it highlights a persistence mechanism that can be difficult to detect through traditional means.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a privileged account with Exchange management permissions.\u003c/li\u003e\n\u003cli\u003eThe attacker uses PowerShell to execute the \u003ccode\u003eSet-CASMailbox\u003c/code\u003e cmdlet.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the \u003ccode\u003eActiveSyncAllowedDeviceIDs\u003c/code\u003e attribute for a target user\u0026rsquo;s mailbox.\u003c/li\u003e\n\u003cli\u003eThe attacker adds a rogue device ID to the list of allowed devices.\u003c/li\u003e\n\u003cli\u003eThe attacker configures a mobile device with the rogue device ID to synchronize with the target mailbox.\u003c/li\u003e\n\u003cli\u003eThe attacker gains persistent access to the target user\u0026rsquo;s email, calendar, and contacts.\u003c/li\u003e\n\u003cli\u003eThe attacker exfiltrates sensitive data from the mailbox.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence even after password changes by continuing to synchronize via the added device.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation could lead to unauthorized access to sensitive email data, including confidential communications, financial information, and personal data. This can result in data breaches, compliance violations, and reputational damage. The scope of the impact depends on the privileges of the compromised account and the sensitivity of the data contained in the targeted mailboxes.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eActiveSyncAllowedDeviceID Added via PowerShell\u003c/code\u003e to your SIEM and tune for your environment to detect suspicious activity.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process-creation logging to capture PowerShell commands for the rule above.\u003c/li\u003e\n\u003cli\u003eReview Exchange audit logs for instances of \u003ccode\u003eSet-CASMailbox\u003c/code\u003e being used to modify \u003ccode\u003eActiveSyncAllowedDeviceIDs\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eImplement multi-factor authentication (MFA) for all accounts, especially those with Exchange management privileges.\u003c/li\u003e\n\u003cli\u003eRegularly audit ActiveSync device configurations to identify unauthorized devices.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-activesync-device-added/","summary":"The rule detects the use of the Exchange PowerShell cmdlet, Set-CASMailbox, to add a new ActiveSync allowed device, potentially allowing attackers to gain persistent access to sensitive email data by adding unauthorized devices.","title":"New ActiveSync Allowed Device Added via PowerShell","url":"https://feed.craftedsignal.io/briefs/2024-01-activesync-device-added/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","CrowdStrike"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","execution","msbuild","proxy-execution","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThe Microsoft Build Engine (MSBuild) is a legitimate tool used by developers to build applications. However, adversaries are known to abuse MSBuild to execute malicious code, leveraging its trusted status to bypass security measures. This technique allows attackers to perform various actions on compromised systems while blending in with legitimate system activity. The observed behavior involves MSBuild being started by system processes like Explorer (explorer.exe) or Windows Management Instrumentation (WMI, wmiprvse.exe). Defenders should be aware of this unusual activity as it signifies a potential defense evasion tactic and unauthorized code execution within the targeted environment. This activity has been observed across environments leveraging Elastic Defend, Microsoft Defender XDR, SentinelOne Cloud Funnel, CrowdStrike, and standard Windows event logging.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system through various means (e.g., phishing, exploitation of vulnerabilities).\u003c/li\u003e\n\u003cli\u003eThe attacker leverages a script or payload that invokes MSBuild.exe.\u003c/li\u003e\n\u003cli\u003eThe script or payload is executed by a system process like explorer.exe or wmiprvse.exe, which is highly unusual for typical MSBuild usage.\u003c/li\u003e\n\u003cli\u003eMSBuild.exe starts with specific command-line arguments that dictate the build process, often involving malicious code.\u003c/li\u003e\n\u003cli\u003eThe malicious code is embedded within an MSBuild project file (.csproj or similar).\u003c/li\u003e\n\u003cli\u003eMSBuild.exe executes the malicious code as part of the build process.\u003c/li\u003e\n\u003cli\u003eThe executed code performs actions such as downloading additional payloads, modifying system configurations, or establishing persistence.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as gaining remote access, exfiltrating data, or deploying ransomware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to a variety of negative outcomes, including unauthorized code execution, system compromise, data theft, and potentially complete system takeover. The use of MSBuild as a proxy execution method allows attackers to evade traditional security controls and blend in with legitimate system activities. This can result in delayed detection and increased dwell time, amplifying the potential damage. Since MSBuild is a trusted Microsoft utility, its abuse can make malicious activity harder to identify and respond to.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Microsoft Build Engine Started by a System Process\u0026rdquo; to your SIEM to detect instances of MSBuild.exe being launched by explorer.exe or wmiprvse.exe (see rules section).\u003c/li\u003e\n\u003cli\u003eEnable process creation logging with command line arguments to capture the full context of MSBuild.exe executions (reference setup instructions in the source URL).\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of MSBuild.exe started by explorer.exe or wmiprvse.exe to determine if they are legitimate or malicious.\u003c/li\u003e\n\u003cli\u003eImplement enhanced monitoring and logging for MSBuild.exe and related processes to detect similar activities in the future, ensuring alerts are configured for rapid response.\u003c/li\u003e\n\u003cli\u003eReview and whitelist any legitimate scripts or administrative tools that leverage MSBuild for authorized tasks to reduce false positives.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-msbuild-system-process/","summary":"Adversaries are leveraging MSBuild, a Microsoft Build Engine, to execute malicious code by initiating it from system processes such as Explorer or WMI to evade defenses and execute unauthorized actions.","title":"MSBuild Started by System Process for Defense Evasion and Execution","url":"https://feed.craftedsignal.io/briefs/2024-01-msbuild-system-process/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Microsoft Defender","Elastic Defend","Elastic Endgame","Trend Micro Security Agent"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","registry-modification","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Trend Micro","Elastic","CrowdStrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers commonly disable or tamper with Microsoft Defender features to evade detection and conceal malicious behavior within compromised Windows environments. This is often achieved by modifying specific registry keys that control the behavior and functionality of Defender components, such as real-time monitoring, exploit protection, and tamper protection itself. Such actions can significantly reduce the effectiveness of endpoint security, allowing malicious activities to proceed undetected. The references point to techniques that disable PUA protection, tamper protection, memory integrity, and real-time protection. This behavior is observed across various attack scenarios, including ransomware deployment and cryptocurrency mining campaigns.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial access is gained through an unspecified vector (e.g., phishing, exploitation of a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker obtains elevated privileges on the system.\u003c/li\u003e\n\u003cli\u003eThe attacker uses an administrative tool like \u003ccode\u003ereg.exe\u003c/code\u003e or PowerShell to modify the registry.\u003c/li\u003e\n\u003cli\u003eThe attacker disables real-time monitoring by setting \u003ccode\u003eHKLM\\SOFTWARE\\Policies\\Microsoft\\Windows Defender\\Real-Time Protection\\DisableRealtimeMonitoring\u003c/code\u003e to 1.\u003c/li\u003e\n\u003cli\u003eThe attacker disables tamper protection by setting \u003ccode\u003eHKLM\\SOFTWARE\\Policies\\Microsoft\\Windows Defender\\Features\\TamperProtection\u003c/code\u003e to 0.\u003c/li\u003e\n\u003cli\u003eThe attacker disables PUA Protection by setting \u003ccode\u003eHKLM\\SOFTWARE\\Policies\\Microsoft\\Windows Defender\\PUAProtection\u003c/code\u003e to 0.\u003c/li\u003e\n\u003cli\u003eWith Defender weakened, the attacker executes malicious payloads, such as ransomware or cryptocurrency miners.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful tampering with Microsoft Defender can lead to a significant degradation of endpoint security posture. This can result in undetected malware infections, data breaches, and system compromise. Disabling Defender features can allow attackers to establish persistence, escalate privileges, and deploy malicious payloads without triggering alerts. The impact can range from individual system compromise to widespread network infection, depending on the attacker\u0026rsquo;s objectives and the extent of the tampering.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Microsoft Windows Defender Tampering - Disable Realtime Monitoring\u0026rdquo; to your SIEM to detect modifications to the \u003ccode\u003eDisableRealtimeMonitoring\u003c/code\u003e registry value.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Microsoft Windows Defender Tampering - Disable Tamper Protection\u0026rdquo; to detect modifications to the \u003ccode\u003eTamperProtection\u003c/code\u003e registry value.\u003c/li\u003e\n\u003cli\u003eMonitor registry modification events, specifically targeting keys associated with Microsoft Defender settings as described in the rule query.\u003c/li\u003e\n\u003cli\u003eInvestigate any process modifying Windows Defender registry settings that are not explicitly authorized, referencing the process exclusions in the rule query.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-defender-tampering/","summary":"Adversaries may disable or tamper with Microsoft Defender features via registry modifications to evade detection and conceal malicious behavior on Windows systems.","title":"Microsoft Defender Tampering via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-defender-tampering/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["group-policy","privilege-escalation","persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eAttackers with domain administrator privileges can abuse Group Policy Objects (GPOs) to deploy malicious payloads across a Windows domain. By creating or modifying scheduled tasks or services via GPOs, an attacker can achieve both privilege escalation and persistence. This involves modifying files such as \u003ccode\u003eScheduledTasks.xml\u003c/code\u003e or \u003ccode\u003eServices.xml\u003c/code\u003e within the SYSVOL share. The modifications are replicated to domain-joined machines when the GPO is applied. This technique allows for remote code execution and control over a significant number of systems from a central point, making it a powerful tool for adversaries targeting enterprise environments. The described rule detects file modifications within specific GPO paths, excluding changes made by the \u003ccode\u003edfsrs.exe\u003c/code\u003e process to reduce false positives. The rule is designed to detect suspicious activities related to scheduled tasks and services within Group Policy settings, helping security teams identify and respond to potential threats originating from compromised domain administrator accounts.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker gains domain administrator privileges through compromised credentials or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eAttacker navigates to the SYSVOL share, typically located at \u003ccode\u003e\\\\\u0026lt;domain\u0026gt;\\SYSVOL\\\u0026lt;domain\u0026gt;\\Policies\\\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eAttacker identifies a GPO to modify or creates a new GPO.\u003c/li\u003e\n\u003cli\u003eAttacker modifies the \u003ccode\u003eScheduledTasks.xml\u003c/code\u003e or \u003ccode\u003eServices.xml\u003c/code\u003e file within the GPO\u0026rsquo;s directory (\u003ccode\u003e\u0026lt;GPO_GUID\u0026gt;\\MACHINE\\Preferences\\ScheduledTasks\\\u003c/code\u003e or \u003ccode\u003e\u0026lt;GPO_GUID\u0026gt;\\MACHINE\\Preferences\\Services\\\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe modified XML file contains instructions to create a scheduled task or service that executes a malicious payload.\u003c/li\u003e\n\u003cli\u003eThe Group Policy Management Console (GPMC) or other tools are used to link the GPO to an organizational unit (OU) containing target computers.\u003c/li\u003e\n\u003cli\u003eTarget machines within the OU receive the updated GPO settings during the next Group Policy refresh cycle (or forced via \u003ccode\u003egpupdate /force\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe scheduled task or service is created on the target machine, executing the attacker\u0026rsquo;s malicious payload and achieving persistence or privilege escalation.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to widespread compromise across the domain. Attackers can execute arbitrary code on numerous systems, potentially leading to data exfiltration, ransomware deployment, or disruption of critical services. The impact can range from minor inconveniences to complete operational shutdown, depending on the nature of the malicious payload and the attacker\u0026rsquo;s objectives. Without proper detection and response mechanisms, such attacks can persist for extended periods, causing significant damage to the organization.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect GPO Scheduled Task/Service Modification via File Event\u003c/code\u003e to detect unauthorized modifications to \u003ccode\u003eScheduledTasks.xml\u003c/code\u003e and \u003ccode\u003eServices.xml\u003c/code\u003e files within GPO paths.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon file creation and modification logging to provide the necessary data for the Sigma rules to function effectively.\u003c/li\u003e\n\u003cli\u003eReview and harden GPO management access controls to limit the potential for abuse by compromised accounts, based on the observed T1484.001 technique.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the deployed rules, focusing on the user accounts and processes involved in the file modifications as described in the overview.\u003c/li\u003e\n\u003cli\u003eMonitor for process execution from unusual locations based on service creation or scheduled task as described in the TTPs.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-gpo-scheduled-task-modification/","summary":"Detection of the creation or modification of new Group Policy based scheduled tasks or services, which can be abused by attackers with domain admin permissions to execute malicious payloads remotely on domain-joined machines, leading to privilege escalation and persistence.","title":"GPO Scheduled Task or Service Creation/Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-gpo-scheduled-task-modification/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Windows Subsystem for Linux","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","execution","windows","wsl"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eThis rule detects attempts to execute programs on the host from the Windows Subsystem for Linux (WSL). Adversaries may enable and use WSL for Linux to avoid detection by executing malicious scripts or binaries, bypassing traditional Windows security mechanisms. The rule identifies suspicious executions initiated by WSL processes, excluding known safe executables, to flag potential misuse for defense evasion. This detection focuses on identifying when a process is spawned by \u003ccode\u003ewsl.exe\u003c/code\u003e or \u003ccode\u003ewslhost.exe\u003c/code\u003e and is not within a known good path. The rule is designed to work with data from Elastic Defend, Crowdstrike, Microsoft Defender XDR, SentinelOne Cloud Funnel, Sysmon, and Windows Security Event Logs.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a Windows system.\u003c/li\u003e\n\u003cli\u003eThe attacker enables the Windows Subsystem for Linux (WSL).\u003c/li\u003e\n\u003cli\u003eThe attacker transfers or creates malicious scripts or binaries within the WSL environment.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the malicious script or binary using a Linux shell within WSL, such as bash.\u003c/li\u003e\n\u003cli\u003eThe WSL environment interacts with the Windows host to execute commands or access resources.\u003c/li\u003e\n\u003cli\u003eThe executed commands perform malicious actions, such as data exfiltration or lateral movement.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages WSL\u0026rsquo;s integration with Windows to evade traditional Windows-based security measures.\u003c/li\u003e\n\u003cli\u003eThe final objective is to compromise the system or network while remaining undetected.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows adversaries to execute malicious code while potentially evading traditional Windows-based security measures. This can lead to system compromise, data theft, or further propagation of malware within the network. The rule\u0026rsquo;s \u003ccode\u003emedium\u003c/code\u003e severity reflects the potential for significant impact, necessitating prompt investigation and response.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eExecution via Windows Subsystem for Linux\u003c/code\u003e to your SIEM to detect potential malicious activity originating from WSL.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) or Windows process creation logs to provide the necessary data for the Sigma rule to function.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on identifying the executed process, parent process (\u003ccode\u003ewsl.exe\u003c/code\u003e or \u003ccode\u003ewslhost.exe\u003c/code\u003e), and associated user account.\u003c/li\u003e\n\u003cli\u003eCorrelate alerts with other security events from Microsoft Defender XDR, SentinelOne, or Crowdstrike to identify related suspicious activities or patterns.\u003c/li\u003e\n\u003cli\u003eImplement exceptions for known administrative scripts or development tools that are frequently executed via WSL to reduce false positives, as outlined in the rule\u0026rsquo;s analysis.\u003c/li\u003e\n\u003cli\u003eMonitor the WSL configuration and installed Linux distributions on affected systems to identify unauthorized changes or installations.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-wsl-child-process-execution/","summary":"This detection identifies attempts to execute programs from the Windows Subsystem for Linux (WSL) to evade detection by flagging suspicious executions initiated by WSL processes and excluding known safe executables.","title":"Execution via Windows Subsystem for Linux","url":"https://feed.craftedsignal.io/briefs/2024-01-wsl-child-process-execution/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Exchange","Elastic Defend"],"_cs_severities":["medium"],"_cs_tags":["collection","execution","powershell","exchange","mailbox"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","Crowdstrike","SentinelOne"],"content_html":"\u003cp\u003eAttackers may target user email to collect sensitive information. The \u003ccode\u003eNew-MailBoxExportRequest\u003c/code\u003e cmdlet is used to export the contents of a primary mailbox or archive to a .pst file. Note that this is done on a per-mailbox basis and this cmdlet is available only in on-premises Exchange. Attackers can abuse this functionality in preparation for exfiltrating contents, which is likely to contain sensitive and strategic data. This activity is typically performed using PowerShell or similar scripting tools and can be difficult to detect without specific monitoring in place. The activity may be part of a larger attack campaign targeting sensitive information.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a compromised system with sufficient privileges to access Exchange PowerShell.\u003c/li\u003e\n\u003cli\u003eThe attacker authenticates to the Exchange server using PowerShell.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the \u003ccode\u003eNew-MailboxExportRequest\u003c/code\u003e cmdlet to initiate the export of a target mailbox to a .pst file. The command may include parameters to filter specific content.\u003c/li\u003e\n\u003cli\u003eThe Exchange server processes the export request, creating a .pst file containing the mailbox data.\u003c/li\u003e\n\u003cli\u003eThe attacker retrieves the exported .pst file from the designated file path.\u003c/li\u003e\n\u003cli\u003eThe attacker may compress and archive the .pst file to reduce its size for exfiltration.\u003c/li\u003e\n\u003cli\u003eThe attacker exfiltrates the .pst file to an external location controlled by the attacker.\u003c/li\u003e\n\u003cli\u003eThe attacker analyzes the .pst file to extract sensitive information such as credentials, financial data, or intellectual property.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows the attacker to gain access to sensitive information contained within the exported mailboxes. This could lead to financial loss, reputational damage, or compromise of intellectual property. Depending on the scope of the export requests, multiple mailboxes may be compromised, impacting a large number of users. The impact is significant because email often contains highly sensitive business communications and data.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation logging to monitor PowerShell execution with command-line arguments (Data Source: Sysmon).\u003c/li\u003e\n\u003cli\u003eImplement the provided Sigma rule to detect the use of \u003ccode\u003eNew-MailboxExportRequest\u003c/code\u003e cmdlet in PowerShell commands.\u003c/li\u003e\n\u003cli\u003eReview the privileges of users with the \u0026ldquo;Mailbox Import Export\u0026rdquo; privilege to ensure that the least privilege principle is being followed.\u003c/li\u003e\n\u003cli\u003eMonitor Windows Security Event Logs for PowerShell activity related to mailbox export requests (Data Source: Windows Security Event Logs).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rules to identify potential malicious activity.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-exchange-mailbox-export/","summary":"Adversaries may use the New-MailboxExportRequest PowerShell cmdlet to export mailboxes in Exchange, potentially leading to sensitive information theft.","title":"Exchange Mailbox Export via PowerShell","url":"https://feed.craftedsignal.io/briefs/2024-01-exchange-mailbox-export/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Crowdstrike"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","registry","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies Windows Registry modifications used to conceal encoded portable executables, a tactic employed by adversaries to evade traditional disk-based detection mechanisms. The rule focuses on detecting registry entries with data strings that match known encoded executable patterns. This technique allows attackers to store malicious code within the registry, making it more difficult to detect using standard file-based scanning methods. The rule is designed to work with Elastic Defend, but also supports data from third-party EDR solutions, including CrowdStrike, Microsoft Defender XDR, and SentinelOne. The detection logic focuses on identifying registry entries with data resembling encoded executables.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to the system (e.g., through compromised credentials or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uses a command-line tool, such as PowerShell or cmd.exe, to interact with the registry.\u003c/li\u003e\n\u003cli\u003eThe attacker encodes a malicious executable using tools like \u003ccode\u003ecertutil\u003c/code\u003e or custom encoding scripts.\u003c/li\u003e\n\u003cli\u003eThe attacker creates or modifies a registry key using \u003ccode\u003ereg.exe\u003c/code\u003e or PowerShell\u0026rsquo;s \u003ccode\u003eSet-ItemProperty\u003c/code\u003e cmdlet.\u003c/li\u003e\n\u003cli\u003eThe encoded executable is written to the registry key\u0026rsquo;s data value. The data string often starts with \u0026ldquo;TVqQAAMAAAAEAAAA*\u0026rdquo;.\u003c/li\u003e\n\u003cli\u003eThe attacker uses another script or command to decode the executable from the registry.\u003c/li\u003e\n\u003cli\u003eThe decoded executable is then executed in memory or written to disk for execution.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as establishing persistence, escalating privileges, or deploying ransomware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to evade traditional disk-based security measures, enabling them to execute malicious code undetected. Attackers can use this technique to establish persistence, escalate privileges, or deploy malware, including ransomware. The rule helps defenders identify systems where this defense evasion technique is being employed.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rules provided in this brief to your SIEM to detect encoded executables stored in the registry.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon registry event logging to provide the necessary data for the provided Sigma rules.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rules to determine if the registry modification is malicious.\u003c/li\u003e\n\u003cli\u003eUse endpoint detection and response (EDR) tools to further analyze suspicious processes associated with the registry modifications.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to prevent the execution of unauthorized executables, even if they are decoded from the registry.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-encoded-executable-registry/","summary":"This rule detects registry write modifications hiding encoded portable executables, indicative of adversary defense evasion by avoiding storing malicious content directly on disk.","title":"Encoded Executable Stored in the Registry","url":"https://feed.craftedsignal.io/briefs/2024-01-encoded-executable-registry/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Microsoft Defender XDR","SentinelOne Cloud Funnel","Crowdstrike"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","windows","registry"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eLocal Security Authority (LSA) protection is a security feature in Windows that prevents unauthorized processes from accessing sensitive information stored in LSASS memory. This protection is enabled through the RunAsPPL registry key. Adversaries may attempt to disable LSA protection by modifying this registry key, allowing them to more easily access credentials stored in LSASS. This technique can be used as part of a broader attack to escalate privileges and move laterally within a network. The rule detects modifications to the \u003ccode\u003eRunAsPPL\u003c/code\u003e registry key that weaken LSA protection. This involves monitoring changes to the registry path \u003ccode\u003e*\\\\SYSTEM\\\\*ControlSet*\\\\Control\\\\Lsa\\\\RunAsPPL\u003c/code\u003e and alerting when the registry data does not contain values that enable protected LSASS modes (\u0026ldquo;1\u0026rdquo;, \u0026ldquo;0x00000001\u0026rdquo;, \u0026ldquo;2\u0026rdquo;, \u0026ldquo;0x00000002\u0026rdquo;).\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access to a system, potentially through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges to an administrator account, if necessary, to gain the required permissions to modify the registry.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the \u003ccode\u003eRunAsPPL\u003c/code\u003e registry key located at \u003ccode\u003eHKLM\\System\\CurrentControlSet\\Control\\Lsa\u003c/code\u003e (or similar path under \u003ccode\u003eControlSet00x\u003c/code\u003e) to a value that disables LSA protection (e.g., setting it to 0). This is often achieved using tools like \u003ccode\u003ereg.exe\u003c/code\u003e or PowerShell.\u003c/li\u003e\n\u003cli\u003eThe attacker may stage the system for a reboot to apply the registry change.\u003c/li\u003e\n\u003cli\u003eAfter the system reboots, LSASS starts without Protected Process Light (PPL) protection, allowing the attacker to access its memory.\u003c/li\u003e\n\u003cli\u003eThe attacker uses credential dumping tools like \u003ccode\u003eMimikatz\u003c/code\u003e to extract credentials from the unprotected LSASS process.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the stolen credentials to move laterally to other systems on the network.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data exfiltration, ransomware deployment, or disruption of services.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful disabling of LSA protection allows attackers to easily extract credentials from LSASS memory. This can lead to widespread compromise of user and service accounts, enabling lateral movement and privilege escalation within the network. The impact could range from data breaches and financial loss to complete system compromise and disruption of critical services.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon registry event logging to detect changes to the \u003ccode\u003eRunAsPPL\u003c/code\u003e registry key (Data Source: Sysmon).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Disabling Lsa Protection via Registry Modification\u0026rdquo; to your SIEM to detect malicious modifications to the \u003ccode\u003eRunAsPPL\u003c/code\u003e registry key.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the process making the change, the user account, and any associated processes (see the \u0026ldquo;investigation_fields\u0026rdquo; in the source).\u003c/li\u003e\n\u003cli\u003eMonitor for unusual process activity after registry modifications, such as the execution of credential dumping tools (e.g., Mimikatz).\u003c/li\u003e\n\u003cli\u003eRegularly review and enforce the principle of least privilege to minimize the number of accounts with permissions to modify sensitive registry keys.\u003c/li\u003e\n\u003cli\u003eUse host isolation when unauthorized LSA-protection weakening is detected and confirmed.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T12:00:00Z","date_published":"2024-01-03T12:00:00Z","id":"/briefs/2024-01-lsass-ppl-disable/","summary":"Adversaries may modify the RunAsPPL registry key to disable LSA protection, which prevents nonprotected processes from reading memory and injecting code, potentially leading to credential access.","title":"Disabling LSA Protection via Registry Modification","url":"https://feed.craftedsignal.io/briefs/2024-01-lsass-ppl-disable/"}],"language":"en","next_url":"/products/microsoft-defender-xdr/page/2/feed.json","title":"CraftedSignal Threat Feed — Microsoft Defender XDR","version":"https://jsonfeed.org/version/1.1"}