{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/products/sentinelone-cloud-funnel/","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":["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":["M365 Defender","Sysmon","Elastic Defend","SentinelOne Cloud Funnel","CrowdStrike Falcon"],"_cs_severities":["medium"],"_cs_tags":["initial-access","rdp","phishing","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers are increasingly using malicious Remote Desktop Protocol (RDP) files to gain initial access to systems. These RDP files, often delivered via spearphishing attachments, contain connection settings that, when opened, can compromise a system. This technique allows adversaries to bypass traditional security measures by leveraging a legitimate tool (mstsc.exe) with a malicious configuration file. The observed activity involves opening RDP files from suspicious locations like Downloads, temporary folders (AppData\\Local\\Temp), and Outlook content cache (INetCache\\Content.Outlook). This campaign has been observed as recently as October 2024, where Midnight Blizzard conducted large-scale spear-phishing using RDP files. Defenders should monitor for the execution of mstsc.exe with RDP files from untrusted locations.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker crafts a spearphishing email containing a malicious RDP file as an attachment.\u003c/li\u003e\n\u003cli\u003eThe victim receives the email and, lured by social engineering, downloads the attached RDP file to a local directory, often the Downloads folder.\u003c/li\u003e\n\u003cli\u003eThe victim double-clicks the RDP file, initiating the execution of \u003ccode\u003emstsc.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003emstsc.exe\u003c/code\u003e reads the connection settings from the RDP file, which may include malicious configurations such as altered gateway settings or credential theft mechanisms.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003emstsc.exe\u003c/code\u003e attempts to establish a remote desktop connection based on the RDP file\u0026rsquo;s settings.\u003c/li\u003e\n\u003cli\u003eIf the connection is successful, the attacker gains unauthorized access to the remote system.\u003c/li\u003e\n\u003cli\u003eThe attacker may then perform reconnaissance, move laterally, and escalate privileges within the compromised network.\u003c/li\u003e\n\u003cli\u003eThe final objective could be data exfiltration, ransomware deployment, or establishing persistent access.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack using malicious RDP files can lead to unauthorized access to sensitive systems and data. The consequences range from data breaches and financial loss to complete system compromise and disruption of operations. The Microsoft Security blog reported a large-scale spear-phishing campaign utilizing RDP files as recently as October 2024. The targets may be across various sectors, with potentially widespread impact depending on the attacker\u0026rsquo;s objectives and the scope of the compromised network.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eRemote Desktop File Opened from Suspicious Path\u003c/code\u003e to your SIEM and tune for your environment, focusing on the specified file paths and \u003ccode\u003emstsc.exe\u003c/code\u003e execution.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging with command-line arguments to capture the execution of \u003ccode\u003emstsc.exe\u003c/code\u003e and the paths of the RDP files being opened.\u003c/li\u003e\n\u003cli\u003eEducate users on the risks associated with opening RDP files from untrusted sources, particularly those received as email attachments.\u003c/li\u003e\n\u003cli\u003eImplement strict email filtering to block or quarantine emails with RDP attachments from external sources.\u003c/li\u003e\n\u003cli\u003eMonitor network connections for unusual RDP traffic originating from systems where suspicious RDP files were executed.\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-rdp-file-attachment/","summary":"Adversaries may abuse RDP files delivered via phishing from suspicious locations to gain unauthorized access to systems.","title":"Remote Desktop File Opened from Suspicious Path","url":"https://feed.craftedsignal.io/briefs/2024-11-rdp-file-attachment/"},{"_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":["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":["M365 Defender","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["execution","command-shell","rundll32"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eAttackers commonly abuse RunDLL32, a legitimate Windows utility, to execute malicious code by hosting it within DLLs. This technique allows adversaries to launch command shells like cmd.exe or PowerShell, effectively bypassing traditional security controls. Defenders should be aware of this technique because it provides a stealthy way for attackers to execute arbitrary commands, potentially leading to further compromise of the system. This activity is detected by monitoring for command shells initiated by RunDLL32, while excluding known benign patterns to reduce false positives. The detection rule was last updated on 2026/05/04 and supports multiple data sources, including Elastic Defend, Microsoft Defender XDR, 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 through an exploit or social engineering.\u003c/li\u003e\n\u003cli\u003eThe attacker uses RunDLL32.exe to execute a malicious DLL.\u003c/li\u003e\n\u003cli\u003eRunDLL32.exe loads the specified DLL into memory.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL contains code to execute a command shell (cmd.exe or powershell.exe).\u003c/li\u003e\n\u003cli\u003eRunDLL32.exe spawns a command shell process.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the command shell to execute commands for reconnaissance.\u003c/li\u003e\n\u003cli\u003eThe attacker may use the command shell to download additional payloads.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the command shell to perform lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to execute arbitrary commands on the compromised system. While the rule is rated \u0026ldquo;low\u0026rdquo; severity, this initial access can lead to credential access (T1552) and further lateral movement within the network. Attackers can potentially gain full control of the system, leading to data theft, system disruption, or other malicious activities.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Command Shell Activity Started via RunDLL32\u0026rdquo; to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to provide the necessary data for this detection.\u003c/li\u003e\n\u003cli\u003eReview the process details of RunDLL32.exe to confirm the parent-child relationship with the command shell, helping to reduce false positives.\u003c/li\u003e\n\u003cli\u003eImplement enhanced monitoring for rundll32.exe and related processes to detect similar activities in the future and improve response times.\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-rundll32-cmd-shell/","summary":"This rule detects command shell activity, such as cmd.exe or powershell.exe, initiated by RunDLL32, a technique commonly abused by attackers to execute malicious code and bypass security controls.","title":"Command Shell Activity Started via RunDLL32","url":"https://feed.craftedsignal.io/briefs/2026-05-rundll32-cmd-shell/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["M365 Defender","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","code-signing","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers may attempt to subvert trust controls by disabling or modifying the code signing policy. This allows them to execute unsigned or self-signed malicious code. This can be achieved by modifying boot configuration data (BCD) settings using the built-in bcdedit.exe utility on Windows. Disabling Driver Signature Enforcement (DSE) allows the loading of untrusted drivers, which can compromise system integrity. The rule identifies commands that can disable the Driver Signature Enforcement feature. The scope of the targeting is broad, as it can affect any Windows system where an attacker gains sufficient privileges to modify the BCD settings. This activity is detected by analyzing process execution events for specific command-line arguments used with bcdedit.exe. The detection 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\u003eThe attacker gains administrative privileges on a Windows system.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003ebcdedit.exe\u003c/code\u003e with arguments to disable driver signature enforcement. Example: \u003ccode\u003ebcdedit.exe /set testsigning on\u003c/code\u003e or \u003ccode\u003ebcdedit.exe /set nointegritychecks on\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003ebcdedit.exe\u003c/code\u003e modifies the Boot Configuration Data (BCD) store.\u003c/li\u003e\n\u003cli\u003eThe system is restarted to apply the changes made to the BCD.\u003c/li\u003e\n\u003cli\u003eThe attacker loads an unsigned or self-signed malicious driver.\u003c/li\u003e\n\u003cli\u003eThe malicious driver executes with kernel-level privileges.\u003c/li\u003e\n\u003cli\u003eThe attacker performs malicious activities such as installing rootkits, bypassing security controls, or stealing sensitive data.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence by ensuring the malicious driver is loaded on subsequent system reboots.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of the code signing policy can lead to the execution of unsigned or self-signed malicious code, which can compromise the integrity and security of the system. Attackers can install rootkits, bypass security controls, or steal sensitive data. The impact can range from individual system compromise to broader network-wide attacks, depending on the attacker\u0026rsquo;s objectives.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Code Signing Policy Modification Through Built-in Tools\u0026rdquo; to your SIEM to detect the execution of \u003ccode\u003ebcdedit.exe\u003c/code\u003e with arguments used to disable code signing (process.args).\u003c/li\u003e\n\u003cli\u003eEnable process creation logging with command line arguments on Windows systems to ensure the Sigma rule can capture the relevant events (logsource).\u003c/li\u003e\n\u003cli\u003eInvestigate any detected instances of code signing policy modification, as this activity is typically not legitimate and can indicate malicious activity. The rule \u003ccode\u003eFirst Time Seen Driver Loaded - df0fd41e-5590-4965-ad5e-cd079ec22fa9\u003c/code\u003e can be used to detect suspicious drivers loaded into the system after the command was executed.\u003c/li\u003e\n\u003cli\u003eEnsure that Driver Signature Enforcement is enabled on all systems.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-04T14:17:05Z","date_published":"2026-05-04T14:17:05Z","id":"/briefs/2024-01-09-code-signing-policy-modification/","summary":"Attackers may attempt to disable or modify code signing policies on Windows systems by using built-in tools like bcdedit.exe in order to execute unsigned or self-signed malicious code.","title":"Code Signing Policy Modification Through Built-in Tools","url":"https://feed.craftedsignal.io/briefs/2024-01-09-code-signing-policy-modification/"},{"_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":["Elastic Defend","SentinelOne Cloud Funnel","Sysmon","Windows Installer"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows","msiexec"],"_cs_type":"advisory","_cs_vendors":["Elastic","SentinelOne","Microsoft"],"content_html":"\u003cp\u003eAdversaries may abuse the Windows Installer service (msiexec.exe) to proxy the execution of malicious payloads, effectively bypassing application control and other security mechanisms. This technique, known as \u0026ldquo;Msiexec\u0026rdquo; proxy execution (T1218.007), involves using msiexec.exe to execute malicious DLLs or scripts. The detection focuses on identifying child processes spawned by MsiExec, particularly those exhibiting network activity. This behavior is atypical for legitimate software installations and updates, making it a strong indicator of potential malicious use. Defenders should be aware of this technique as it allows attackers to blend in with legitimate system processes. The Elastic detection rule, updated on 2026-05-04, aims to identify this suspicious activity across multiple data sources including Elastic Defend, Sysmon, and SentinelOne.\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 through an exploit or social engineering.\u003c/li\u003e\n\u003cli\u003eAttacker leverages msiexec.exe to execute a malicious MSI package with a \u003ccode\u003e/v\u003c/code\u003e parameter, commonly used to pass verbose logging options, potentially hiding malicious commands.\u003c/li\u003e\n\u003cli\u003eThe malicious MSI package contains custom actions that execute arbitrary code.\u003c/li\u003e\n\u003cli\u003eMsiexec.exe spawns a child process (e.g., powershell.exe, cmd.exe, or another executable) to carry out malicious actions.\u003c/li\u003e\n\u003cli\u003eThe child process establishes a network connection to an external server or performs DNS lookups, possibly for command and control (C2) communication or to download additional payloads.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the network connection to download and execute further tools or scripts.\u003c/li\u003e\n\u003cli\u003eThe attacker performs lateral movement within the network.\u003c/li\u003e\n\u003cli\u003eThe final objective could be 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 exploitation allows attackers to bypass application control and execute arbitrary code on the system. This can lead to malware installation, data theft, or complete system compromise. While the exact number of victims is not specified in the provided source, the technique can be applied across various sectors. The impact can range from individual workstation compromises to large-scale breaches affecting entire organizations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eMsiExec Child Process with Unusual Executable and Network Connection\u003c/code\u003e to detect suspicious msiexec.exe child processes initiating network connections based on unusual executable paths.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) and network connection logging (Event ID 3) to provide the necessary data for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rules, focusing on the process tree, command-line arguments, and network destinations.\u003c/li\u003e\n\u003cli\u003eReview and whitelist legitimate software installations and automated deployment tools that use MsiExec and require network access to minimize false positives, as detailed in the \u0026ldquo;False positive analysis\u0026rdquo; section of the source material.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-10-26T12:00:00Z","date_published":"2024-10-26T12:00:00Z","id":"/briefs/2024-10-msiexec-network-connection/","summary":"Detection of MsiExec spawning child processes that initiate network connections, potentially indicating abuse of Windows Installers for malware delivery and defense evasion.","title":"MsiExec Child Process Spawning Network Connections for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-10-msiexec-network-connection/"},{"_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","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":["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":["Elastic Defend","SentinelOne Cloud Funnel","Microsoft Teams","Google Chrome","Mozilla Firefox","Opera","Cisco WebEx","Discord","WhatsApp","Zoom","Brave Browser","Slack","thunderbird.exe"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","persistence","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","SentinelOne","Microsoft","Google","Mozilla","Opera","Cisco","Discord","WhatsApp","Zoom","Brave"],"content_html":"\u003cp\u003eThis detection rule focuses on identifying suspicious child processes of communication applications such as Slack, Cisco Webex, Microsoft Teams, Discord, WhatsApp, Zoom, and Thunderbird on Windows operating systems. Attackers may attempt to masquerade as legitimate processes or exploit vulnerabilities in these applications to execute malicious code. The rule monitors for the creation of child processes by these communication apps and checks if those child processes are unexpected, untrusted, or lack a valid code signature. This detection is crucial because successful exploitation can lead to unauthorized access, data exfiltration, or further compromise of the system. The rule has been actively maintained since August 2023, with updates as recent as May 2026, indicating its relevance and ongoing refinement to address emerging threats.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eUser launches a communication application (e.g., Slack, Teams, Webex).\u003c/li\u003e\n\u003cli\u003eThe communication application executes a vulnerable or compromised component.\u003c/li\u003e\n\u003cli\u003eThe compromised component spawns a child process (e.g., powershell.exe, cmd.exe).\u003c/li\u003e\n\u003cli\u003eThe child process executes a malicious command or script.\u003c/li\u003e\n\u003cli\u003eThe script attempts to download additional payloads from an external source.\u003c/li\u003e\n\u003cli\u003eThe payload executes, establishing persistence through registry modification or scheduled tasks.\u003c/li\u003e\n\u003cli\u003eThe attacker gains remote access to the system.\u003c/li\u003e\n\u003cli\u003eData exfiltration or lateral movement within the network occurs.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to the compromise of sensitive data, installation of malware, and potential lateral movement within the organization\u0026rsquo;s network. By exploiting communication applications, attackers can gain access to internal communications, confidential documents, and user credentials. The number of affected users and the extent of the damage depend on the compromised application and the attacker\u0026rsquo;s objectives. If successful, this attack may lead 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\u003eDeploy the Sigma rule \u003ccode\u003eSuspicious Communication App Child Process\u003c/code\u003e to your SIEM to detect anomalous child processes spawned by communication applications and tune for your environment.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging with command line arguments in Windows to ensure that the Sigma rule has the necessary data to function correctly (logsource: \u003ccode\u003eprocess_creation\u003c/code\u003e, product: \u003ccode\u003ewindows\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the rule and review the command line arguments of the spawned processes to identify potential malicious activity.\u003c/li\u003e\n\u003cli\u003eImplement application whitelisting to restrict the execution of unauthorized applications and reduce the attack surface.\u003c/li\u003e\n\u003cli\u003eEnsure that all communication applications are updated to the latest versions to patch known vulnerabilities and reduce the risk of exploitation.\u003c/li\u003e\n\u003cli\u003eExamine the network activity of the affected system to identify any suspicious outbound connections that may indicate data exfiltration or communication with a command and control server, referencing the setup guide.\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-suspicious-comm-app-child-process/","summary":"The detection rule identifies suspicious child processes spawned from communication applications on Windows systems, potentially indicating masquerading or exploitation of vulnerabilities within these applications.","title":"Suspicious Child Processes from Communication Applications","url":"https://feed.craftedsignal.io/briefs/2024-01-suspicious-comm-app-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":["Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["defense-evasion","command-and-control","windows","msxsl"],"_cs_type":"advisory","_cs_vendors":["Elastic","SentinelOne"],"content_html":"\u003cp\u003eMsXsl.exe is a Windows utility designed to transform XML data using XSLT stylesheets. Adversaries are known to abuse this utility to execute malicious scripts, bypassing application control and other security measures. This behavior is often used as a defense evasion technique to download or execute malicious payloads. This activity has been observed since at least March 2020. The abuse of msxsl.exe allows attackers to establish command and control or exfiltrate sensitive data without being easily detected, as the tool is a signed Microsoft binary. This matters for defenders because it highlights the need to monitor legitimate system utilities for anomalous behavior, specifically network connections to external IP addresses.\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 leverages msxsl.exe to execute a malicious script.\u003c/li\u003e\n\u003cli\u003eMsxsl.exe initiates a network connection to an external IP address.\u003c/li\u003e\n\u003cli\u003eThe script downloads a malicious payload from the external server.\u003c/li\u003e\n\u003cli\u003eThe downloaded payload is executed on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker establishes a command and control channel through the network connection.\u003c/li\u003e\n\u003cli\u003eThe attacker performs data exfiltration via the established C2 channel.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eCompromised systems can be used for further malicious activities, including data theft, lateral movement, and deployment of additional malware. Successful exploitation can lead to sensitive data exfiltration, disruption of services, or complete system compromise. The low risk score does not represent impact, but instead reflects that the behavior is not always malicious, and may be a feature of normal software operation.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon network connection logging to monitor msxsl.exe network activity.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Network Connection via MsXsl\u0026rdquo; to your SIEM and tune for your environment to detect suspicious network connections originating from msxsl.exe.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the destination IP address and the parent process of msxsl.exe.\u003c/li\u003e\n\u003cli\u003eWhitelist legitimate uses of msxsl.exe in your environment based on known good processes or applications to reduce false positives.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-30T10:00:00Z","date_published":"2024-01-30T10:00:00Z","id":"/briefs/2024-01-msxsl-network-connection/","summary":"Msxsl.exe, a legitimate Windows utility, is being abused by adversaries to make network connections to non-local IPs for command and control or data exfiltration, potentially bypassing security measures.","title":"MsXsl.exe Network Connection for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-msxsl-network-connection/"},{"_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","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":["M365 Defender","SentinelOne Cloud Funnel","Elastic Defend","Elastic Endgame"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","ads","file-creation","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","SentinelOne","Elastic"],"content_html":"\u003cp\u003eThis detection focuses on identifying the creation of Alternate Data Streams (ADS) on Windows systems, a technique often employed by adversaries to conceal malicious code or data within seemingly benign files. Attackers leverage scripting engines and command interpreters to write ADS to various file types, including executables, documents, and media files. This activity is uncommon in legitimate workflows, making it a valuable indicator of potential compromise. The rule is designed to trigger on file creation events where the process creating the file is a known script or command interpreter (cmd.exe, powershell.exe, etc.) and the target file has a suspicious extension. The detection excludes common legitimate ADS usage patterns. This technique is used for defense evasion, allowing malware to persist without being easily detected by traditional security measures.\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 a command interpreter (cmd.exe, powershell.exe, etc.) or scripting engine (wscript.exe, cscript.exe) to execute malicious code.\u003c/li\u003e\n\u003cli\u003eThe malicious code creates an Alternate Data Stream (ADS) on a targeted file (e.g., an executable, document, or image). The targeted file\u0026rsquo;s extension could be pdf, dll, exe, dat, etc.\u003c/li\u003e\n\u003cli\u003eThe attacker hides malicious code or data within the ADS, making it less visible to standard file system scans and security tools. The ADS is written to a file path using the \u003ccode\u003eC:\\\\*:\\*\u003c/code\u003e syntax.\u003c/li\u003e\n\u003cli\u003eThe attacker may rename or clean up any staging files to further conceal their activity.\u003c/li\u003e\n\u003cli\u003eThe attacker can then execute the hidden code within the ADS, or use the ADS to store configuration data for later use.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence by using the ADS to store and execute malicious code, bypassing typical file-based security measures.\u003c/li\u003e\n\u003cli\u003eThe ultimate goal is to maintain unauthorized access to the system, potentially leading to data exfiltration, lateral movement, 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 hide malicious code within legitimate files, evading detection by traditional security measures. This can lead to prolonged persistence on compromised systems, enabling data theft, ransomware deployment, or other malicious activities. While the specific number of victims is unknown, this technique is broadly applicable across Windows environments, potentially affecting a wide range of organizations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSuspicious ADS File Creation via Cmd\u003c/code\u003e to detect ADS creation events initiated by cmd.exe.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSuspicious ADS File Creation via PowerShell\u003c/code\u003e to detect ADS creation events initiated by powershell.exe.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 15 (FileCreateStreamHash) to provide detailed information about ADS creation events, as referenced in the rule\u0026rsquo;s setup instructions.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by these rules, focusing on the file paths, creating processes, and command-line arguments involved, as detailed in the rule\u0026rsquo;s triage and analysis notes.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-26T18:00:00Z","date_published":"2024-01-26T18:00:00Z","id":"/briefs/2024-01-ads-file-creation/","summary":"Detects suspicious creation of Alternate Data Streams (ADS) on targeted files using script or command interpreters, indicative of malware hiding in ADS for defense evasion.","title":"Suspicious Alternate Data Stream (ADS) File Creation","url":"https://feed.craftedsignal.io/briefs/2024-01-ads-file-creation/"},{"_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","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","command-and-control","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","SentinelOne"],"content_html":"\u003cp\u003eAttackers often abuse the \u003ccode\u003erundll32.exe\u003c/code\u003e utility to execute malicious Dynamic Link Libraries (DLLs), blending their activity with legitimate system operations. This detection identifies instances where \u003ccode\u003erundll32.exe\u003c/code\u003e establishes outbound network connections, particularly when executed without command-line arguments. Such behavior deviates from typical usage and may indicate command and control (C2) activity or other malicious actions. The rule is designed to detect command and control activity where adversaries are using \u003ccode\u003erundll32.exe\u003c/code\u003e without arguments to make external network connections. The rule uses data from Elastic Defend, Sysmon, and SentinelOne to detect this behavior. The rule specifically excludes connections to well-known private and reserved IP ranges to reduce 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 a Windows system, possibly through phishing or exploiting a software vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to execute a malicious DLL using \u003ccode\u003erundll32.exe\u003c/code\u003e without specifying arguments, which is an anomaly.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003erundll32.exe\u003c/code\u003e is invoked with a command line resembling: \u003ccode\u003erundll32.exe \u0026lt;path_to_dll\u0026gt;\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL initiates an outbound network connection to an external IP address.\u003c/li\u003e\n\u003cli\u003eThe network connection attempts to bypass firewall rules by masquerading as a legitimate system process.\u003c/li\u003e\n\u003cli\u003eThe attacker uses this connection to establish a command and control channel.\u003c/li\u003e\n\u003cli\u003eData exfiltration or further exploitation activities occur over the established C2 channel.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, such as data theft, ransomware deployment, or system compromise.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to establish command and control channels on compromised systems, leading to potential data exfiltration, lateral movement within the network, and deployment of ransomware. This can result in significant financial losses, reputational damage, and disruption of business operations. The impact is broad, affecting any Windows environment where \u003ccode\u003erundll32.exe\u003c/code\u003e is used.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Unusual Network Connection via RunDLL32\u003c/code\u003e to your SIEM and tune for your environment to detect unusual network connections made by \u003ccode\u003erundll32.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation and network connection logging to capture necessary events for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the parent processes of \u003ccode\u003erundll32.exe\u003c/code\u003e and the destination IP addresses of the network connections.\u003c/li\u003e\n\u003cli\u003eReview and harden firewall rules to prevent unauthorized outbound connections from system processes like \u003ccode\u003erundll32.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of unsigned or untrusted DLLs via \u003ccode\u003erundll32.exe\u003c/code\u003e.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-26T10:00:00Z","date_published":"2024-01-26T10:00:00Z","id":"/briefs/2024-01-rundll32-network-connection/","summary":"The rule detects unusual outbound network connections made by rundll32.exe, specifically when executed with minimal arguments, which may indicate command and control activity or defense evasion tactics on Windows systems.","title":"Unusual Network Connection via RunDLL32","url":"https://feed.craftedsignal.io/briefs/2024-01-rundll32-network-connection/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Defender XDR","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["persistence","bits","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic"],"content_html":"\u003cp\u003eThe Background Intelligent Transfer Service (BITS) is a Windows service used for asynchronous, prioritized, and throttled file transfers. Attackers can abuse BITS to establish persistence by using the \u003ccode\u003eSetNotifyCmdLine\u003c/code\u003e method to execute a program after a BITS job completes or enters a specific state. This technique allows adversaries to run arbitrary code with elevated privileges, bypassing traditional security measures. The detection rule identifies suspicious processes initiated by BITS, excluding known legitimate executables like \u003ccode\u003eWerFaultSecure.exe\u003c/code\u003e, \u003ccode\u003eWerFault.exe\u003c/code\u003e, \u003ccode\u003ewermgr.exe\u003c/code\u003e, and \u003ccode\u003edirectxdatabaseupdater.exe\u003c/code\u003e. This behavior can be employed to maintain access to a compromised system, even after a reboot or user logout. Defenders need to monitor BITS activity for unusual command-line executions to detect and prevent potential persistence 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 system through other means (e.g., phishing, exploitation of a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uses the BITSAdmin tool or PowerShell cmdlets to create a new BITS job.\u003c/li\u003e\n\u003cli\u003eThe attacker configures the BITS job to download a malicious payload or execute a malicious script.\u003c/li\u003e\n\u003cli\u003eThe attacker utilizes the \u003ccode\u003eSetNotifyCmdLine\u003c/code\u003e method to set a command that will be executed upon job completion or a specified state change.\u003c/li\u003e\n\u003cli\u003eThe BITS service executes the specified command, which can be a script interpreter (e.g., \u003ccode\u003epowershell.exe\u003c/code\u003e, \u003ccode\u003ecmd.exe\u003c/code\u003e) or a malicious executable.\u003c/li\u003e\n\u003cli\u003eThe malicious command downloads or executes further payloads, establishing persistence on the system.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistent access, allowing them to execute commands, steal data, or perform 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 maintain persistent access to compromised systems. This can lead to data theft, further malware deployment, or complete system compromise. The BITS service runs with elevated privileges, so any command executed via \u003ccode\u003eSetNotifyCmdLine\u003c/code\u003e will also run with those privileges. This persistence mechanism is difficult to detect because BITS is a legitimate Windows service, and its activity can be easily masked as normal system operations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor process creation events for processes spawned by \u003ccode\u003esvchost.exe\u003c/code\u003e with arguments containing \u0026ldquo;BITS\u0026rdquo; but not in the exclusion list (WerFaultSecure.exe, WerFault.exe, wermgr.exe, directxdatabaseupdater.exe) using the \u0026ldquo;Persistence via BITS Job Notify Cmdline\u0026rdquo; rule.\u003c/li\u003e\n\u003cli\u003eImplement the Sigma rule \u0026ldquo;Detect Suspicious BITS Job Creation\u0026rdquo; to identify unusual BITS job creation activities.\u003c/li\u003e\n\u003cli\u003eReview BITS job configurations on systems to identify and remove any unauthorized or suspicious jobs.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture detailed information about process execution, including parent-child relationships and command-line arguments.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-26T10:00:00Z","date_published":"2024-01-26T10:00:00Z","id":"/briefs/2024-01-26-bits-persistence/","summary":"Adversaries can achieve persistence by abusing the Background Intelligent Transfer Service (BITS) SetNotifyCmdLine method to execute a program after a job finishes, leading to arbitrary code execution and system compromise.","title":"Persistence via BITS Job Notify Cmdline","url":"https://feed.craftedsignal.io/briefs/2024-01-26-bits-persistence/"},{"_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":["M365 Defender","SentinelOne Cloud Funnel","Crowdstrike"],"_cs_severities":["medium"],"_cs_tags":["execution","windows","scripting","archive"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers commonly use archive files (ZIP, RAR, 7z) to deliver malicious scripts, such as JScript and VBScript, to Windows systems. This technique allows them to bypass some initial security checks and deliver payloads that can execute arbitrary code. The \u0026ldquo;Windows Script Execution from Archive\u0026rdquo; detection identifies instances where Windows Script Host (wscript.exe) is launched from temporary directories containing extracted archive contents. This activity can indicate a user has opened a malicious archive, leading to potential malware execution. This detection focuses on the parent-child process relationship, where explorer.exe, winrar.exe, or 7zFM.exe spawns wscript.exe to execute scripts from the temp directory.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eA user receives a malicious archive file (e.g., ZIP, RAR, 7z) via email or downloads it from a website.\u003c/li\u003e\n\u003cli\u003eThe user opens the archive file using a file archiver tool like Explorer, WinRAR, or 7-Zip.\u003c/li\u003e\n\u003cli\u003eThe archiver extracts the contents, including a malicious JScript (.js) or VBScript (.vbs) file, to a temporary directory, such as \u003ccode\u003e\\Users\\*\\AppData\\Local\\Temp\\7z*\\\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe user (or the archiver tool) inadvertently executes the extracted script using Windows Script Host (wscript.exe).\u003c/li\u003e\n\u003cli\u003eWscript.exe executes the malicious script, which may perform a variety of actions, such as downloading and executing additional payloads.\u003c/li\u003e\n\u003cli\u003eThe script establishes persistence via registry modification, adding a run key to execute upon system startup.\u003c/li\u003e\n\u003cli\u003eThe script connects to a command-and-control server to receive further instructions.\u003c/li\u003e\n\u003cli\u003eThe attacker gains control of the compromised system and begins lateral movement.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack of this nature can lead to arbitrary code execution on the victim\u0026rsquo;s machine, potentially resulting in data theft, malware installation, or complete system compromise. While the number of affected organizations is not specified, the technique is broadly applicable to any Windows environment where users handle archive files, potentially affecting numerous individuals and organizations across various sectors.\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 capture the execution of wscript.exe and its arguments.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Script Execution from Archive\u0026rdquo; to your SIEM to identify suspicious script execution patterns.\u003c/li\u003e\n\u003cli\u003eMonitor process activity for wscript.exe and other scripting engines executing from temporary directories.\u003c/li\u003e\n\u003cli\u003eConfigure endpoint security solutions to block execution of scripts from common temporary directories.\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-script-exec-archive/","summary":"This rule identifies attempts to execute Jscript/Vbscript files from an archive file, a common delivery method for malicious scripts on Windows systems.","title":"Windows Script Execution from Archive File","url":"https://feed.craftedsignal.io/briefs/2024-01-script-exec-archive/"},{"_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 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","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":["m365_defender","Elastic Defend","SentinelOne Cloud Funnel","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["process_injection","privilege_escalation","defense_evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThe Windows Service Host process (svchost.exe) is a critical system component that hosts multiple Windows services to optimize resource utilization. Certain services running under svchost.exe are not expected to spawn child processes. Attackers may inject malicious code into these \u0026ldquo;childless\u0026rdquo; svchost processes to execute unauthorized commands and evade traditional detection methods. This detection rule identifies anomalies by monitoring child processes of svchost.exe instances associated with services known to be childless, such as \u003ccode\u003eWdiSystemHost\u003c/code\u003e, \u003ccode\u003eLicenseManager\u003c/code\u003e, and \u003ccode\u003eStorSvc\u003c/code\u003e, flagging potential process injection or exploitation attempts. The rule aims to identify deviations from the expected behavior of these services, providing an early warning of potential malicious activity.\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 through an exploit or by leveraging existing credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker injects malicious code into a running svchost.exe process associated with a childless service like \u003ccode\u003eWdiSystemHost\u003c/code\u003e or \u003ccode\u003eStorSvc\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe injected code spawns a child process from the targeted svchost.exe instance. This could involve executing a system utility or a custom payload.\u003c/li\u003e\n\u003cli\u003eThe child process executes commands or performs actions dictated by the injected code, such as establishing a reverse shell or downloading additional payloads.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the spawned process to perform reconnaissance activities, gathering information about the system and network.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges, potentially leveraging vulnerabilities or misconfigurations accessible from the compromised svchost process.\u003c/li\u003e\n\u003cli\u003eThe attacker moves laterally to other systems on the network, using the compromised system as a pivot point.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their final objective, which may include data exfiltration, ransomware deployment, or establishing persistent access.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to privilege escalation, allowing attackers to gain control of the compromised system and potentially the entire network. Attackers can use the compromised system as a staging ground for further attacks, exfiltrate sensitive data, deploy ransomware, or disrupt critical services. The medium severity score reflects the potential for significant impact if the activity is not detected and contained promptly.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eUnusual Svchost Child Process - Childless Service\u003c/code\u003e to your SIEM to detect potential process injection attacks targeting svchost.exe.\u003c/li\u003e\n\u003cli\u003eTune the rule by adding known false positives to the exclusion list, such as \u003ccode\u003eWerFault.exe\u003c/code\u003e, \u003ccode\u003eWerFaultSecure.exe\u003c/code\u003e, and \u003ccode\u003ewermgr.exe\u003c/code\u003e to reduce alert fatigue.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging via Sysmon (Event ID 1) with command line details for better visibility into spawned processes, as described in the \u003ca href=\"https://ela.st/sysmon-event-1-setup\"\u003esetup guide\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the rule, focusing on the process details and parent-child relationships to determine the legitimacy of the spawned process.\u003c/li\u003e\n\u003cli\u003eConsider using endpoint detection and response (EDR) solutions like Elastic Defend for enhanced visibility and automated response capabilities, as the rule is designed for data generated by \u003ca href=\"https://www.elastic.co/security/endpoint-security\"\u003eElastic Defend\u003c/a\u003e.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-04T12:00:00Z","date_published":"2024-01-04T12:00:00Z","id":"/briefs/2024-01-unusual-svchost-child-process/","summary":"This detection identifies unusual child processes of Service Host (svchost.exe) that traditionally do not spawn child processes, potentially indicating code injection or exploitation.","title":"Unusual Service Host Child Process - Childless Service","url":"https://feed.craftedsignal.io/briefs/2024-01-unusual-svchost-child-process/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows","Defender XDR","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows","masquerading"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Intel","IBM"],"content_html":"\u003cp\u003eThis detection identifies process execution from suspicious default Windows directories. Attackers may hide malware in trusted paths to evade defenses, making it difficult for analysts to distinguish between legitimate and malicious activity. The detection focuses on identifying processes running from directories like C:\\PerfLogs, C:\\Users\\Public, and various Windows subdirectories (e.g., C:\\Windows\\Tasks, C:\\Windows\\AppReadiness), where executable files are not typically expected to reside. The detection excludes known legitimate processes like SpeechUXWiz.exe, SystemSettings.exe, TrustedInstaller.exe and other Intel and IBM executables to reduce false positives. This technique is often used to bypass security controls or take advantage of existing exceptions applied to these directories. This activity was observed being used by threat actors in the Siestagraph campaign.\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 drops a malicious executable into a suspicious directory like C:\\Users\\Public or C:\\Windows\\Tasks.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the malware from the unusual directory. This might be achieved using \u003ccode\u003ecmd.exe\u003c/code\u003e or \u003ccode\u003epowershell.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe executed malware establishes persistence by creating a scheduled task or modifying registry keys.\u003c/li\u003e\n\u003cli\u003eThe malware connects to a command-and-control (C2) server to receive further instructions.\u003c/li\u003e\n\u003cli\u003eThe C2 server instructs the malware to perform reconnaissance on the network.\u003c/li\u003e\n\u003cli\u003eThe malware attempts to move laterally to other systems on the network using techniques like pass-the-hash or exploiting vulnerabilities.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as data exfiltration, ransomware deployment, or establishing long-term access to the network.\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, persistence on the system, and further compromise of the network. Attackers can use this technique to bypass security controls and evade detection, potentially leading to data breaches, financial loss, or disruption of services. While the rule itself has a medium severity, the impact of a successful attack using this technique can be severe, depending on the attacker\u0026rsquo;s objectives and the compromised data.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Process Execution from Unusual Directory\u0026rdquo; to your SIEM and tune for your environment to detect suspicious process execution.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule to determine if the process execution is legitimate or malicious.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging, specifically Event ID 4688 with command line process auditing, to ensure the Sigma rule has the necessary data to function effectively.\u003c/li\u003e\n\u003cli\u003eReview and harden permissions on the listed suspicious directories to prevent unauthorized file creation and execution.\u003c/li\u003e\n\u003cli\u003eBlock execution of unsigned or untrusted executables from these directories using application control solutions.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-04T12:00:00Z","date_published":"2024-01-04T12:00:00Z","id":"/briefs/2024-01-process-execution-from-unusual-directory/","summary":"Adversaries may execute processes from unusual default Windows directories to masquerade malware and evade defenses by blending in with trusted paths, making malicious activity harder to detect.","title":"Process Execution from Suspicious Windows Directories","url":"https://feed.craftedsignal.io/briefs/2024-01-process-execution-from-unusual-directory/"},{"_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":["Elastic Defend","SentinelOne Cloud Funnel","PowerShell"],"_cs_severities":["medium"],"_cs_tags":["lateral-movement","powershell","remoting"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies potential lateral movement through the exploitation of Windows PowerShell remoting. PowerShell remoting is a feature that enables administrators and attackers to execute commands on remote Windows systems. The detection focuses on identifying incoming network connections on ports 5985 (HTTP) and 5986 (HTTPS), the default ports used for PowerShell Remoting, followed by the execution of processes spawned by \u003ccode\u003ewsmprovhost.exe\u003c/code\u003e, the Windows Remote Management process host. This activity, when originating from unexpected sources, may indicate unauthorized access and lateral movement within a network. The rule is designed to detect suspicious activity by monitoring network traffic and process execution, flagging potential unauthorized remote executions, and enabling security teams to respond swiftly.\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 network, possibly through phishing or exploiting a vulnerability on an internet-facing system.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages PowerShell remoting to initiate a connection to a target system on ports 5985 or 5986.\u003c/li\u003e\n\u003cli\u003eThe target system accepts the incoming PowerShell Remoting connection.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003ewsmprovhost.exe\u003c/code\u003e process is launched on the target system to facilitate the remote PowerShell session.\u003c/li\u003e\n\u003cli\u003eThe attacker executes commands remotely, spawning child processes from \u003ccode\u003ewsmprovhost.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to escalate privileges or move laterally to other systems within the network using the remote PowerShell session.\u003c/li\u003e\n\u003cli\u003eThe attacker uses tools such as \u003ccode\u003enet.exe\u003c/code\u003e or \u003ccode\u003ePsExec\u003c/code\u003e over the remote PowerShell session to further propagate.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as data exfiltration or deploying ransomware, by leveraging the established remote session.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of PowerShell Remoting for lateral movement can lead to widespread compromise within an organization. An attacker could gain control over multiple systems, potentially leading to data breaches, system outages, or ransomware deployment. The number of affected systems could range from a few critical servers to a significant portion of the network, depending on the attacker\u0026rsquo;s objectives and the organization\u0026rsquo;s security posture. The impact could include financial losses, reputational damage, and disruption of business operations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eIncoming Execution via PowerShell Remoting\u003c/code\u003e to your SIEM to detect suspicious PowerShell remoting activity and tune for your environment.\u003c/li\u003e\n\u003cli\u003eMonitor network connections to ports 5985 and 5986, and investigate any unauthorized or unexpected traffic using the \u003ccode\u003enetwork_connection\u003c/code\u003e log source.\u003c/li\u003e\n\u003cli\u003eInvestigate processes spawned by \u003ccode\u003ewsmprovhost.exe\u003c/code\u003e for unusual or malicious activity using the \u003ccode\u003eprocess_creation\u003c/code\u003e log source.\u003c/li\u003e\n\u003cli\u003eWhitelist authorized administrative IP addresses or user accounts that frequently perform remote management tasks, as mentioned in the false positives analysis.\u003c/li\u003e\n\u003cli\u003eReview and document automated scripts or scheduled tasks that use PowerShell Remoting for system maintenance, then create exceptions for their specific process names or execution paths.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T18:53:23Z","date_published":"2024-01-03T18:53:23Z","id":"/briefs/2024-01-03-powershell-remoting/","summary":"This rule identifies remote execution via Windows PowerShell remoting, which allows a user to run any Windows PowerShell command on one or more remote computers, potentially indicating lateral movement.","title":"Incoming Execution via PowerShell Remoting","url":"https://feed.craftedsignal.io/briefs/2024-01-03-powershell-remoting/"},{"_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":["Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","proxy-execution","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","SentinelOne"],"content_html":"\u003cp\u003eInstallUtil.exe is a legitimate Windows utility used for installing and uninstalling server resources. Adversaries abuse InstallUtil.exe to execute malicious code under the guise of legitimate processes, often to evade detection. This technique allows attackers to proxy execution through a trusted system binary, potentially bypassing application control and security monitoring. The detection rule identifies suspicious network activity by monitoring InstallUtil.exe\u0026rsquo;s outbound connections, flagging potential misuse by alerting on the initial network connection attempt. This activity is detected via the Elastic EQL rule \u0026ldquo;InstallUtil Process Making Network Connections.\u0026rdquo;\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access through an undisclosed method.\u003c/li\u003e\n\u003cli\u003eThe attacker uses InstallUtil.exe to execute a malicious .NET assembly.\u003c/li\u003e\n\u003cli\u003eInstallUtil.exe loads the malicious assembly into its process.\u003c/li\u003e\n\u003cli\u003eThe malicious assembly executes code that establishes an outbound network connection.\u003c/li\u003e\n\u003cli\u003eThe connection is used for command and control (C2) or data exfiltration.\u003c/li\u003e\n\u003cli\u003eThe attacker may use the C2 channel to download and execute further payloads.\u003c/li\u003e\n\u003cli\u003eThe attacker performs 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 arbitrary code execution within the context of a trusted Windows process (InstallUtil.exe), bypassing application control and potentially evading detection. This could result in a compromised system, data exfiltration, or further malicious activities within the network. The scope of impact depends on the attacker\u0026rsquo;s objectives and the level of access gained, potentially affecting entire organizations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable process creation logging and network connection logging via Sysmon or Elastic Defend to provide the data needed for the rules below.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;InstallUtil Network Connection\u0026rdquo; to your SIEM and tune for your environment to detect suspicious outbound network connections from InstallUtil.exe.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rule by examining the parent process of InstallUtil.exe, destination IP addresses, and associated activities.\u003c/li\u003e\n\u003cli\u003eImplement network monitoring and alerting for unusual outbound connections from critical systems to enhance detection of similar threats in the future.\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-installutil-network-connection/","summary":"Detection of InstallUtil.exe making outbound network connections, which can indicate adversaries leveraging it to execute code and evade detection by proxying execution through a trusted system binary.","title":"InstallUtil Process Making Network Connections for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-installutil-network-connection/"},{"_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","SentinelOne Cloud Funnel","Backup Exec","Veeam","Microsoft Power BI Enterprise Gateway","Trend Micro"],"_cs_severities":["medium"],"_cs_tags":["impact","backup deletion","ransomware"],"_cs_type":"advisory","_cs_vendors":["Elastic","Veritas","Veeam","Trend Micro","Microsoft"],"content_html":"\u003cp\u003eThis rule identifies the deletion of backup files, specifically those created by Veeam and Veritas Backup Exec, through unexpected processes on Windows systems. The rule aims to detect potential attempts to inhibit system recovery by adversaries, particularly in the context of ransomware attacks. Attackers often target backup files to eliminate recovery options for victims. This detection focuses on identifying file deletion events where the process responsible for the deletion does not belong to the trusted backup software suite. The rule excludes known legitimate processes and directories like Trend Micro\u0026rsquo;s, Microsoft Exchange Mailbox Assistants, and the Recycle Bin to minimize false positives. The original Elastic detection rule was created in October 2021 and last updated May 4, 2026.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAdversary gains initial access to the target Windows system.\u003c/li\u003e\n\u003cli\u003eThe attacker performs reconnaissance to identify backup file locations.\u003c/li\u003e\n\u003cli\u003eThe attacker uses a non-backup related process (e.g., \u003ccode\u003ecmd.exe\u003c/code\u003e, \u003ccode\u003epowershell.exe\u003c/code\u003e) to delete backup files.\u003c/li\u003e\n\u003cli\u003eThe attacker targets Veeam backup files with extensions \u003ccode\u003eVBK\u003c/code\u003e, \u003ccode\u003eVIB\u003c/code\u003e, and \u003ccode\u003eVBM\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe attacker targets Veritas Backup Exec files with the \u003ccode\u003eBKF\u003c/code\u003e extension.\u003c/li\u003e\n\u003cli\u003eThe deletion events are logged by the endpoint detection system.\u003c/li\u003e\n\u003cli\u003eThe detection rule triggers, identifying the anomalous deletion activity based on file extension and process context.\u003c/li\u003e\n\u003cli\u003eSuccessful deletion of backups impairs the victim\u0026rsquo;s ability to recover from ransomware or other destructive attacks.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful deletion of backup files can severely impact an organization\u0026rsquo;s ability to recover from a ransomware attack or other data loss events. Without viable backups, the victim organization may be forced to pay a ransom or face significant data loss and business disruption. This tactic directly increases the attacker\u0026rsquo;s leverage and potential financial gain. The rule\u0026rsquo;s documentation cites a report from AdvIntel detailing backup removal solutions seen with Conti ransomware.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eUnexpected Veeam Backup File Deletion\u003c/code\u003e to your SIEM and tune for your environment to detect unexpected deletion of Veeam backup files.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eUnexpected Veritas Backup File Deletion\u003c/code\u003e to your SIEM and tune for your environment to detect unexpected deletion of Veritas Backup Exec files.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by these rules to determine the source of the deletion and assess potential impact.\u003c/li\u003e\n\u003cli\u003eEnable endpoint file event logging to capture file deletion events, which are crucial for the Sigma rules.\u003c/li\u003e\n\u003cli\u003eReview process execution chains (parent process tree) for unknown processes to identify the root cause of unexpected file deletions.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T18:12:00Z","date_published":"2024-01-03T18:12:00Z","id":"/briefs/2024-01-03-backup-deletion/","summary":"This detection identifies the deletion of backup files by processes outside of the backup suite, specifically targeting Veritas and Veeam backups, which may indicate an attempt to prevent recovery from ransomware.","title":"Third-party Backup Files Deleted via Unexpected Process","url":"https://feed.craftedsignal.io/briefs/2024-01-03-backup-deletion/"},{"_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","SentinelOne Cloud Funnel","OneDrive","Chrome","Opera","Fiddler","PowerToys","Vivaldi","Zen Browser","WaveBrowser","MicrosoftEdgeCP"],"_cs_severities":["low"],"_cs_tags":["command-and-control","webservice","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","Google","BraveSoftware","Opera","Vivaldi","Wavesor Software","Discord","Telegram","Facebook","Trello","GitHub","Supabase"],"content_html":"\u003cp\u003eThis detection rule, sourced from Elastic, identifies potential command and control (C2) activity by detecting connections to commonly abused web services. Adversaries often leverage popular web services like pastebin, GitHub, Dropbox, and Discord to mask malicious communications within legitimate network traffic. This technique makes it challenging for defenders to distinguish between normal user activity and malicious C2 traffic. The rule focuses on Windows systems and monitors DNS queries to identify processes communicating with a predefined list of services known to be abused by attackers. The rule was last updated on 2026-05-04 and is designed to work with data from Elastic Defend and SentinelOne Cloud Funnel. The goal is to identify anomalous network connections originating from unusual processes.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eA user on a Windows host unknowingly executes a malicious file (e.g., via phishing or drive-by download).\u003c/li\u003e\n\u003cli\u003eThe malicious file executes a process outside of typical program directories (e.g., \u003ccode\u003eC:\\Windows\\Temp\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThis process initiates a DNS query to a domain associated with a commonly abused web service (e.g., \u003ccode\u003epastebin.com\u003c/code\u003e, \u003ccode\u003egithubusercontent.com\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe DNS query resolves to an IP address, and a network connection is established to the web service.\u003c/li\u003e\n\u003cli\u003eThe malicious process uploads or downloads data from the web service, potentially containing commands for the compromised host or exfiltrated data.\u003c/li\u003e\n\u003cli\u003eThe web service acts as an intermediary, relaying commands from the attacker to the compromised host or exfiltrated data from the compromised host to the attacker.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the C2 channel to perform further actions on the compromised host, such as lateral movement or data theft.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack using common web services for C2 can lead to data exfiltration, system compromise, and further propagation within the network. The low severity suggests a focus on detecting early-stage C2 activity, which if left unchecked, could escalate into a significant incident. The usage of popular web services makes detection difficult, requiring careful analysis and tuning to avoid false positives.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Connection to Commonly Abused Web Services\u0026rdquo; to your SIEM and tune it for your environment to minimize false positives.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon DNS query logging to accurately capture DNS requests for improved detection capabilities, activating the \u0026ldquo;DNS Query to Commonly Abused Web Services\u0026rdquo; rule.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by this rule, focusing on the process execution chain and network connections to determine the legitimacy of the activity, referencing the investigation steps described in the rule documentation.\u003c/li\u003e\n\u003cli\u003eReview and update the list of excluded processes in the Sigma rule to reflect your organization\u0026rsquo;s approved software and reduce false positives.\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-common-web-services-c2/","summary":"This rule detects command and control (C2) communications that use common web services to hide malicious activity on Windows hosts by identifying network connections to commonly abused web services from processes outside of known legitimate program locations, indicating potential exfiltration or C2 activity blended with legitimate traffic.","title":"Detection of Command and Control Activity via Common Web Services","url":"https://feed.craftedsignal.io/briefs/2024-01-common-web-services-c2/"},{"_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","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":["M365 Defender","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","proxy-execution","openssh","application-control-bypass"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eThis detection identifies attempts to execute commands through a proxy using the Windows OpenSSH client (ssh.exe or sftp.exe). Attackers may abuse this behavior to evade application control policies by leveraging the trusted Windows OpenSSH binaries. The technique involves using the \u003ccode\u003eProxyCommand\u003c/code\u003e or \u003ccode\u003eLocalCommand\u003c/code\u003e options with the OpenSSH client to execute arbitrary commands on the target system. The rule focuses on detecting command lines containing potentially malicious commands such as PowerShell, schtasks, mshta, msiexec, cmd, or script execution, indicating a possible attempt to bypass security measures. The detection logic is applicable to Windows systems.\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 the Windows OpenSSH client (ssh.exe or sftp.exe) with either the \u003ccode\u003eProxyCommand\u003c/code\u003e or \u003ccode\u003eLocalCommand\u003c/code\u003e option.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003eProxyCommand\u003c/code\u003e or \u003ccode\u003eLocalCommand\u003c/code\u003e parameter specifies a command to be executed locally on the system.\u003c/li\u003e\n\u003cli\u003eThe command includes potentially malicious payloads such as PowerShell commands, scheduled tasks manipulation (schtasks), or execution of other LOLBINs (Living Off the Land Binaries) like mshta or msiexec.\u003c/li\u003e\n\u003cli\u003eThe OpenSSH client executes the specified command.\u003c/li\u003e\n\u003cli\u003eThe malicious command performs actions such as downloading and executing additional payloads, creating scheduled tasks for persistence, or executing arbitrary code.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objectives, such as gaining further access to the system, escalating privileges, or deploying malware.\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 affected system. Attackers can bypass application control mechanisms, execute arbitrary code, and establish persistence. This can result in data theft, system disruption, or further propagation of the attack within the network. The severity of the impact depends on the privileges of the account running the OpenSSH client and the specific actions performed by the malicious commands.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable process creation logging with command line details to capture the execution of ssh.exe and sftp.exe with malicious parameters.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eProxy Execution via Windows OpenSSH\u003c/code\u003e to your SIEM to detect suspicious OpenSSH client executions with malicious commands in the command line.\u003c/li\u003e\n\u003cli\u003eMonitor for the creation of child processes from ssh.exe or sftp.exe, as this can indicate the execution of malicious commands specified in the \u003ccode\u003eProxyCommand\u003c/code\u003e or \u003ccode\u003eLocalCommand\u003c/code\u003e options.\u003c/li\u003e\n\u003cli\u003eReview and restrict the usage of \u003ccode\u003ePermitLocalCommand\u003c/code\u003e in OpenSSH server configurations to prevent attackers from executing commands locally on the system after a connection is established.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T14:22:00Z","date_published":"2024-01-03T14:22:00Z","id":"/briefs/2024-01-openssh-proxy-execution/","summary":"Detection of command execution via proxy using the Windows OpenSSH client (ssh.exe or sftp.exe) to bypass application control using trusted Windows binaries.","title":"Proxy Execution via Windows OpenSSH Client","url":"https://feed.craftedsignal.io/briefs/2024-01-openssh-proxy-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":["Elastic Defend","SentinelOne Cloud Funnel","Windows"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","command-and-control","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThe detection rule identifies unusual instances of dllhost.exe making outbound network connections, which may indicate adversarial command and control activity. Dllhost.exe is a legitimate Windows process used to host DLL services. Adversaries may exploit it for stealthy command and control by initiating unauthorized network connections to non-local IPs. This approach helps in identifying potential threats by focusing on unusual network behaviors associated with this process. The rule aims to detect activity related to defense evasion, where adversaries use system binaries to proxy execution. The detection logic relies on identifying dllhost.exe processes initiating network connections to destinations outside of commonly used private IP ranges.\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 exploitation).\u003c/li\u003e\n\u003cli\u003eThe attacker executes a malicious DLL file on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker uses dllhost.exe to host and execute the malicious DLL.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL initiates a network connection to an external IP address, bypassing traditional process-based network monitoring.\u003c/li\u003e\n\u003cli\u003eThe attacker establishes a command and control (C2) channel via the dllhost.exe process.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the C2 channel to send commands and receive data from the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker performs lateral movement within the network.\u003c/li\u003e\n\u003cli\u003eThe attacker exfiltrates sensitive data from the compromised network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to the establishment of a covert command and control channel, allowing attackers to remotely control the compromised system. This can result in data theft, further compromise of the network, and potential financial loss. The references point to APT29 activity, suggesting sophisticated actors may leverage this technique.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation (Event ID 1) and network connection (Event ID 3) logging to enhance visibility of process execution and network activity (\u003ca href=\"https://ela.st/sysmon-event-1-setup\"\u003ehttps://ela.st/sysmon-event-1-setup\u003c/a\u003e, \u003ca href=\"https://ela.st/sysmon-event-3-setup\"\u003ehttps://ela.st/sysmon-event-3-setup\u003c/a\u003e).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eUnusual Network Connection via DllHost\u003c/code\u003e to your SIEM to detect suspicious outbound connections from dllhost.exe.\u003c/li\u003e\n\u003cli\u003eInvestigate and whitelist legitimate software updates or enterprise applications that use dllhost.exe for network communications to reduce false positives, as described in the rule\u0026rsquo;s analysis notes.\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-unusual-dllhost-network-connection/","summary":"The rule identifies unusual instances of dllhost.exe making outbound network connections to non-local IPs, which may indicate adversarial Command and Control activity and defense evasion.","title":"Unusual Network Connection via DllHost","url":"https://feed.craftedsignal.io/briefs/2024-01-unusual-dllhost-network-connection/"},{"_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":["Defender XDR","Endpoint Security","UEMS_Agent","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","filter-driver","fltMC.exe","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","ManageEngine","Bitdefender","SentinelOne"],"content_html":"\u003cp\u003eThe Filter Manager Control Program (fltMC.exe) is a Windows utility used to manage filter drivers, also known as minifilters. These minifilters are leveraged by various security products, including EDR, antivirus solutions, and data loss prevention tools, to intercept and modify I/O requests. Attackers can abuse fltMC.exe to unload these minifilters, effectively disabling or circumventing the security measures they provide. This allows malicious actors to operate without detection, potentially leading to data breaches, malware infections, or other harmful activities. This technique has been observed being used to disable security products such as Bitdefender, SentinelOne and ManageEngine Endpoint Central.\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., via compromised credentials or exploit).\u003c/li\u003e\n\u003cli\u003eAttacker executes \u003ccode\u003efltMC.exe\u003c/code\u003e with administrative privileges.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003efltMC.exe\u003c/code\u003e attempts to unload a specific filter driver (minifilter).\u003c/li\u003e\n\u003cli\u003eThe operating system processes the request to unload the specified filter driver.\u003c/li\u003e\n\u003cli\u003eIf successful, the targeted minifilter is removed from the active filter stack.\u003c/li\u003e\n\u003cli\u003eSecurity software relying on the unloaded minifilter ceases to function correctly, leaving a security gap.\u003c/li\u003e\n\u003cli\u003eAttacker performs malicious actions, such as deploying malware or exfiltrating sensitive data, without the protection of the disabled filter driver.\u003c/li\u003e\n\u003cli\u003eAttacker 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 allows attackers to disable or circumvent security controls, increasing the likelihood of successful malware infections, data breaches, and other malicious activities. The scope of impact depends on the specific filter driver unloaded and the security products it supports. Disabling a critical EDR minifilter could leave the entire system vulnerable, while disabling a less critical filter might only impact a subset of security features.\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\u003efltMC.exe\u003c/code\u003e with the \u003ccode\u003eunload\u003c/code\u003e argument to identify potential evasion attempts (see Sigma rule \u0026ldquo;Potential Evasion via Filter Manager\u0026rdquo;).\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of \u003ccode\u003efltMC.exe\u003c/code\u003e execution where the parent process is not a known and trusted system management tool.\u003c/li\u003e\n\u003cli\u003eImplement strict access controls to limit the ability of users to execute \u003ccode\u003efltMC.exe\u003c/code\u003e or modify filter driver configurations.\u003c/li\u003e\n\u003cli\u003eReview the list of exclusions in the provided EQL query to identify any legitimate software that may be generating false positives.\u003c/li\u003e\n\u003cli\u003eEnsure that endpoint security solutions are properly configured and monitored to detect and prevent unauthorized filter driver modifications.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to activate the rules above.\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-filter-manager-evasion/","summary":"Adversaries may abuse the Filter Manager Control Program (fltMC.exe) to unload filter drivers, thereby evading security software defenses such as malware detection and file system monitoring.","title":"Potential Defense Evasion via Filter Manager (fltMC.exe)","url":"https://feed.craftedsignal.io/briefs/2024-01-filter-manager-evasion/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","SentinelOne Cloud Funnel","Corretto JDK","UEM Proxy Server","UEM Core","dbeaver.exe","Docker","Chrome","Internet Explorer","PyCharm Community Edition","Firefox","VirtualBox","Puppet","nexpose","Silverfort AD Adapter","Nessus","VMware View","Advanced Port Scanner","DesktopCentral Agent","LanGuard","SAP BusinessObjects","SuperScan","ZSATunnel"],"_cs_severities":["medium"],"_cs_tags":["kerberoasting","credential-access","lateral-movement","windows"],"_cs_type":"threat","_cs_vendors":["Elastic","SentinelOne","Amazon","BlackBerry","DBeaver","Docker","Google","Microsoft","JetBrains","Mozilla","Oracle","Puppet Labs","Rapid7","Silverfort","Tenable","VMware","GFI","SAP","Zscaler"],"content_html":"\u003cp\u003eThis detection identifies unusual processes initiating network connections to the standard Kerberos port (88) on Windows systems. Typically, the \u003ccode\u003elsass.exe\u003c/code\u003e process handles Kerberos traffic on domain-joined hosts. The rule aims to detect processes other than \u003ccode\u003elsass.exe\u003c/code\u003e communicating with the Kerberos port, which could indicate malicious activity such as Kerberoasting (T1558.003) or Pass-the-Ticket (T1550.003). The detection is designed to work with data from Elastic Defend and SentinelOne Cloud Funnel. This can help security teams identify potential credential access attempts and lateral movement within the network.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker compromises a user account or system within the domain.\u003c/li\u003e\n\u003cli\u003eThe attacker executes a malicious binary or script (e.g., PowerShell) on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe malicious process attempts to request Kerberos service tickets (TGS) for various services within the domain. This is done by connecting to the Kerberos port (88) on a domain controller.\u003c/li\u003e\n\u003cli\u003eThe attacker uses tools like \u003ccode\u003eRubeus\u003c/code\u003e or \u003ccode\u003eKerberoast.ps1\u003c/code\u003e to enumerate and request TGS tickets.\u003c/li\u003e\n\u003cli\u003eThe unusual process (not \u003ccode\u003elsass.exe\u003c/code\u003e) sends Kerberos traffic to the domain controller.\u003c/li\u003e\n\u003cli\u003eThe attacker extracts the Kerberos tickets from memory or network traffic.\u003c/li\u003e\n\u003cli\u003eThe attacker cracks the offline TGS tickets to obtain service account passwords (Kerberoasting).\u003c/li\u003e\n\u003cli\u003eThe attacker uses the compromised service account credentials to move laterally within the network or access sensitive data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful Kerberoasting or Pass-the-Ticket attack can lead to unauthorized access to sensitive resources and lateral movement within the network. Attackers can compromise service accounts with elevated privileges, potentially leading to domain-wide compromise. Detection of this behavior can prevent attackers from gaining access to critical assets. While the exact number of victims and sectors targeted are unknown, this technique is widely used by various threat actors in targeted attacks.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Kerberos Traffic from Unusual Process\u0026rdquo; Sigma rule to your SIEM and tune for your environment. Enable network connection logging to capture the necessary traffic.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rule, focusing on the process execution chain and potential malicious binaries.\u003c/li\u003e\n\u003cli\u003eReview event ID 4769 for suspicious ticket requests as mentioned in the rule\u0026rsquo;s documentation.\u003c/li\u003e\n\u003cli\u003eExamine host services for suspicious entries as outlined in the original Elastic detection rule using Osquery.\u003c/li\u003e\n\u003cli\u003eMonitor for processes connecting to port 88, filtering out legitimate Kerberos clients like \u003ccode\u003elsass.exe\u003c/code\u003e, using the \u0026ldquo;Detect Kerberos Traffic from Non-Standard Process\u0026rdquo; Sigma rule.\u003c/li\u003e\n\u003cli\u003eInvestigate processes identified by the rule and compare them to the list of legitimate processes to identify unauthorized connections to the Kerberos port.\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-kerberoasting-unusual-process/","summary":"Detects network connections to the standard Kerberos port from an unusual process other than lsass.exe, potentially indicating Kerberoasting or Pass-the-Ticket activity on Windows systems.","title":"Kerberos Traffic from Unusual Process","url":"https://feed.craftedsignal.io/briefs/2024-01-03-kerberoasting-unusual-process/"},{"_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":["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","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["defense-evasion","proxy-execution","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","SentinelOne"],"content_html":"\u003cp\u003eAttackers frequently exploit built-in system utilities to bypass security measures and execute malicious code. This technique, known as \u0026ldquo;Living off the Land,\u0026rdquo; allows them to blend in with legitimate system activity, making detection more challenging. This threat brief focuses on identifying unusual network connections originating from Windows system utilities that are not typically associated with network communication. This behavior is often indicative of an attacker leveraging these tools for purposes such as downloading payloads, establishing command and control, or exfiltrating data. The utilities of concern include: Microsoft.Workflow.Compiler.exe, bginfo.exe, cdb.exe, cmstp.exe, csi.exe, dnx.exe, fsi.exe, ieexec.exe, iexpress.exe, odbcconf.exe, rcsi.exe and xwizard.exe. Defenders should monitor for network activity from these processes to identify potential malicious activity.\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 or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages a system utility such as \u003ccode\u003ecmstp.exe\u003c/code\u003e to execute malicious code.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003ecmstp.exe\u003c/code\u003e is invoked with a malicious INF file, leading to the execution of arbitrary commands.\u003c/li\u003e\n\u003cli\u003eThe executed code initiates a network connection to an external server.\u003c/li\u003e\n\u003cli\u003eThe connection is used to download a secondary payload, such as a reverse shell or malware.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the downloaded payload to establish a persistent presence on the system.\u003c/li\u003e\n\u003cli\u003eThe attacker performs lateral movement to other systems on the network.\u003c/li\u003e\n\u003cli\u003eThe attacker exfiltrates sensitive data from compromised systems to a remote server.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to a compromised system with unauthorized code execution, data exfiltration, and potential lateral movement within the network. Due to the low severity and the high probability of false positives, this rule should be tuned for specific environments and paired with other detection mechanisms. This may lead to data breaches, financial loss, or reputational damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eImplement the Sigma rules provided in this brief to detect unusual network connections from system utilities within your environment.\u003c/li\u003e\n\u003cli\u003eMonitor process execution events for the utilities listed in the rule query to identify potential abuse of these tools.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 1 (Process Creation) and Event ID 3 (Network Connection) logging for enhanced visibility into process execution and network activity.\u003c/li\u003e\n\u003cli\u003eCorrelate detections from this rule with other security alerts and logs to gain a more complete understanding of the attack.\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-process-network/","summary":"Adversaries may leverage unusual system utilities such as Microsoft.Workflow.Compiler.exe, bginfo.exe, cdb.exe, cmstp.exe, csi.exe, dnx.exe, fsi.exe, ieexec.exe, iexpress.exe, odbcconf.exe, rcsi.exe and xwizard.exe to execute code and evade detection, as identified by network connections originating from these processes.","title":"Unusual System Utilities Initiating Network Connections","url":"https://feed.craftedsignal.io/briefs/2024-01-unusual-process-network/"},{"_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","SolarWinds.BusinessLayerHost.exe","SolarWinds.BusinessLayerHostx64.exe","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["supply-chain","execution","solarwinds"],"_cs_type":"advisory","_cs_vendors":["Elastic","SolarWinds","SentinelOne"],"content_html":"\u003cp\u003eThis detection rule identifies suspicious child processes initiated by SolarWinds.BusinessLayerHost.exe or SolarWinds.BusinessLayerHostx64.exe, excluding known legitimate operations. Adversaries may exploit the trusted SolarWinds processes to execute unauthorized programs with elevated privileges, bypassing security controls. The rule focuses on Windows systems and is designed to detect activity indicative of post-compromise actions following a supply chain attack. This detection is crucial for organizations that utilize SolarWinds software, as malicious actors could leverage compromised SolarWinds installations to gain unauthorized access and execute arbitrary code within the network.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial compromise of the SolarWinds software supply chain (T1195.002).\u003c/li\u003e\n\u003cli\u003eMalicious code is injected into SolarWinds.BusinessLayerHost.exe or SolarWinds.BusinessLayerHostx64.exe.\u003c/li\u003e\n\u003cli\u003eThe compromised SolarWinds process spawns a suspicious child process.\u003c/li\u003e\n\u003cli\u003eThe child process executes a malicious command or binary, attempting to evade detection.\u003c/li\u003e\n\u003cli\u003eThe child process leverages Native APIs (T1106) to perform privileged actions.\u003c/li\u003e\n\u003cli\u003eLateral movement or data exfiltration may occur from the compromised host.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack can lead to the execution of arbitrary code on systems running SolarWinds software. This can result in data theft, system compromise, and further propagation of the attack throughout the network. Organizations in various sectors utilizing SolarWinds products are potentially at risk. The impact may include loss of sensitive data, disruption of critical services, and reputational damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSuspicious SolarWinds Child Process - CommandLine\u003c/code\u003e to detect potentially malicious child processes of SolarWinds.BusinessLayerHost.exe or SolarWinds.BusinessLayerHostx64.exe.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eSuspicious SolarWinds Child Process - Executable\u003c/code\u003e to detect execution of unusual executables as child processes of SolarWinds.BusinessLayerHost.exe or SolarWinds.BusinessLayerHostx64.exe.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging with command line details on Windows systems to ensure the Sigma rules have sufficient data.\u003c/li\u003e\n\u003cli\u003eReview and tune the rules for false positives based on legitimate SolarWinds child processes in your environment, updating the exclusion lists in the rules accordingly, referencing the \u0026ldquo;false_positives\u0026rdquo; section 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-solarwinds-child-process/","summary":"Detection of unusual child processes spawned by SolarWinds processes may indicate malicious program execution, potentially bypassing security controls.","title":"Suspicious SolarWinds Child Process Execution","url":"https://feed.craftedsignal.io/briefs/2024-01-solarwinds-child-process/"},{"_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":["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":["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","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":["Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["low"],"_cs_tags":["psexec","lateral-movement","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eThis detection identifies the execution of PsExec, a dual-use tool commonly employed for both legitimate administration and malicious lateral movement. PsExec, part of the Sysinternals Suite, allows for remote command execution with elevated privileges, often abused by attackers to disable security controls and move laterally within a network. This rule specifically detects the creation of \u003ccode\u003ePsExec.exe\u003c/code\u003e followed by a network connection initiated by the process, which is a strong indicator of potential malicious activity. While PsExec has legitimate uses, its prevalence in attack scenarios necessitates careful monitoring. The rule is designed to work with data from Elastic Defend, 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 within the network (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uploads or transfers the PsExec tool (\u003ccode\u003ePsExec.exe\u003c/code\u003e) to the compromised host, potentially using SMB shares or other file transfer methods.\u003c/li\u003e\n\u003cli\u003eThe attacker executes PsExec with the \u003ccode\u003e-accepteula\u003c/code\u003e flag, which suppresses the license dialog, potentially indicating a first-time execution on the machine.\u003c/li\u003e\n\u003cli\u003ePsExec establishes a network connection to a remote target system, leveraging SMB/Windows Admin Shares (T1021.002) to facilitate remote command execution.\u003c/li\u003e\n\u003cli\u003eThe attacker uses PsExec to execute commands on the remote system, potentially with SYSTEM privileges, to install malware, gather credentials, or perform reconnaissance.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the newly compromised system as a pivot point to move laterally to other systems within the network, repeating the process.\u003c/li\u003e\n\u003cli\u003eThe attacker escalates privileges on multiple systems.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their 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 widespread compromise across the network. Attackers can leverage PsExec to gain control over critical systems, disable security controls, and exfiltrate sensitive data. Lateral movement facilitated by PsExec can enable attackers to rapidly expand their footprint within an organization, impacting numerous systems and services. While the rule\u0026rsquo;s severity is low due to the dual-use nature of PsExec, the potential impact of unchecked lateral movement is significant.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003ePsExec Network Connection\u003c/code\u003e to your SIEM and tune the \u003ccode\u003eprocess.executable\u003c/code\u003e and \u003ccode\u003eprocess.parent.executable\u003c/code\u003e filters for your environment to reduce false positives.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 1 (Process Creation) and Event ID 3 (Network Connection) logging for enhanced visibility into PsExec activity.\u003c/li\u003e\n\u003cli\u003eReview and enforce the principle of least privilege to limit the accounts that can run PsExec and access sensitive systems.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the \u003ccode\u003ePsExec Network Connection\u003c/code\u003e rule promptly to determine if the activity is legitimate or malicious.\u003c/li\u003e\n\u003cli\u003eMonitor network connections originating from systems where PsExec is executed using the \u003ccode\u003ePsExec Outbound Network Connection\u003c/code\u003e Sigma 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-psexec-lateral-movement/","summary":"The rule identifies the use of PsExec.exe making a network connection, indicative of potential lateral movement by adversaries executing commands with SYSTEM privileges on Windows systems to disable defenses.","title":"PsExec Lateral Movement via Network Connection","url":"https://feed.craftedsignal.io/briefs/2024-01-psexec-lateral-movement/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["M365 Defender","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["dns-tunneling","command-and-control","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eAttackers can abuse DNS protocol for command and control and/or data exfiltration by exploiting network rules that allow DNS communication with external resources. This technique, known as DNS tunneling, involves encoding data within DNS queries to transmit commands, malicious files, or exfiltrate sensitive information to attacker-controlled DNS servers. Detection focuses on identifying anomalous patterns of nslookup.exe usage, specifically a high volume of executions with explicit query types originating from a single host within a short timeframe. This activity may bypass traditional security controls that monitor standard network traffic, enabling covert communication channels.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker compromises a host within the network.\u003c/li\u003e\n\u003cli\u003eThe attacker executes \u003ccode\u003enslookup.exe\u003c/code\u003e to perform DNS queries with specific query types (e.g., \u003ccode\u003e-querytype=TXT\u003c/code\u003e, \u003ccode\u003e-qt=A\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eThe attacker encodes data (commands, files, or exfiltrated data) into the DNS query.\u003c/li\u003e\n\u003cli\u003eThe compromised host sends multiple DNS requests to a rogue DNS server controlled by the attacker.\u003c/li\u003e\n\u003cli\u003eThe attacker receives the DNS queries and decodes the data.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the tunneled command to further compromise the internal network.\u003c/li\u003e\n\u003cli\u003eThe attacker exfiltrates data to the attacker-controlled server.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful DNS tunneling allows attackers to establish covert communication channels, bypassing traditional security measures. This can lead to command and control of compromised systems, exfiltration of sensitive data, and further propagation within the network. The impact includes potential data breaches, system compromise, and prolonged attacker presence due to the difficulty in detecting covert DNS traffic.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Suspicious Nslookup DNS Tunneling Activity\u0026rdquo; to your SIEM to detect potential DNS tunneling attempts.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging (Event ID 1) to capture \u003ccode\u003enslookup.exe\u003c/code\u003e executions and their command-line arguments.\u003c/li\u003e\n\u003cli\u003eInspect network traffic logs for unusually high volumes of DNS queries originating from individual hosts.\u003c/li\u003e\n\u003cli\u003eMonitor DNS query logs for encoded or unusual data patterns within DNS query names.\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-dns-tunneling-nslookup/","summary":"Detection of multiple nslookup.exe executions with explicit query types from a single host, potentially indicating command and control activity via DNS tunneling, where attackers abuse DNS for data infiltration or exfiltration.","title":"Potential DNS Tunneling via NsLookup","url":"https://feed.craftedsignal.io/briefs/2024-01-dns-tunneling-nslookup/"},{"_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":["M365 Defender","Elastic Defend","SentinelOne Cloud Funnel","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["lateral-movement","defense-evasion","registry-modification"],"_cs_type":"advisory","_cs_vendors":["Microsoft","SentinelOne","Crowdstrike","Elastic"],"content_html":"\u003cp\u003eThis detection rule identifies modifications to the \u003ccode\u003eNullSessionPipe\u003c/code\u003e registry setting in Windows. This setting defines named pipes that can be accessed without authentication, facilitating anonymous connections. Adversaries may exploit this by modifying the registry to enable lateral movement, allowing unauthorized access to network resources. By adding specific pipes to the \u003ccode\u003eNullSessionPipes\u003c/code\u003e registry key, an attacker can make services accessible without requiring authentication. This rule focuses on flagging modifications that introduce new accessible pipes, which could indicate malicious intent. The targeted configuration is located under \u003ccode\u003eHKLM\\SYSTEM\\CurrentControlSet\\Services\\LanmanServer\\Parameters\u003c/code\u003e. The registry key \u003ccode\u003eNullSessionPipes\u003c/code\u003e is of particular interest when its values change.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial compromise of a system within the network.\u003c/li\u003e\n\u003cli\u003eThe attacker gains elevated privileges on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the Windows Registry, specifically the \u003ccode\u003eHKLM\\SYSTEM\\CurrentControlSet\\Services\\LanmanServer\\Parameters\\NullSessionPipes\u003c/code\u003e key. They add a new pipe name to this key, which will allow unauthenticated access to that named pipe.\u003c/li\u003e\n\u003cli\u003eThe attacker uses \u003ccode\u003ereg.exe\u003c/code\u003e or PowerShell to modify the registry, potentially using commands like \u003ccode\u003ereg add\u003c/code\u003e or \u003ccode\u003eSet-ItemProperty\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eA remote system attempts to connect to the newly accessible named pipe on the compromised system without authenticating.\u003c/li\u003e\n\u003cli\u003eThe attacker exploits the now-accessible service or application associated with the named pipe to execute commands or transfer data.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages this access to move laterally within the network, compromising additional systems.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful modification of the \u003ccode\u003eNullSessionPipes\u003c/code\u003e registry setting can lead to unauthorized access to sensitive resources and lateral movement within the network. By enabling anonymous access to named pipes, attackers can potentially bypass authentication mechanisms and gain control over critical systems. While the direct number of victims is not specified, the impact can be significant, particularly in organizations where shared resources and services rely on secure authentication protocols.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Windows Registry auditing to capture changes to the \u003ccode\u003eNullSessionPipes\u003c/code\u003e registry key. This will allow you to detect unauthorized modifications as described in the overview.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;NullSessionPipe Registry Modification\u0026rdquo; to your SIEM and tune for your environment to identify malicious activity related to named pipe modifications.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule, focusing on the specific named pipes being added or modified in the registry event details, as detailed in the rule\u0026rsquo;s description.\u003c/li\u003e\n\u003cli\u003eRegularly review and validate the legitimacy of existing entries in the \u003ccode\u003eNullSessionPipes\u003c/code\u003e registry key to identify and remove any unauthorized pipes.\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-nullsessionpipe-modification/","summary":"Attackers modify the NullSessionPipe registry setting in Windows to enable anonymous access to named pipes, potentially facilitating lateral movement and unauthorized access to network resources.","title":"NullSessionPipe Registry Modification for Lateral Movement","url":"https://feed.craftedsignal.io/briefs/2024-01-nullsessionpipe-modification/"},{"_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":["Amazon Assistant","TeamViewer","Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","system-binary-proxy-execution","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Amazon","TeamViewer","SentinelOne","Elastic"],"content_html":"\u003cp\u003eMshta.exe is a legitimate Windows utility used to execute Microsoft HTML Application (HTA) files. Adversaries exploit it to run malicious scripts, leveraging its trusted status to bypass security measures. This activity can be difficult to detect because Mshta.exe is a signed Microsoft binary. This detection identifies suspicious network activity by Mshta.exe, excluding known benign processes, to flag potential threats. Legitimate uses of Mshta.exe include software updates, installations, and automation scripts using HTA files. This rule helps identify unauthorized network connections indicative of malicious intent and flags suspicious use of mshta.exe.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access through an unknown method, such as phishing or exploiting a software vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker executes a malicious script, such as VBScript or JavaScript, using Mshta.exe.\u003c/li\u003e\n\u003cli\u003eMshta.exe interprets and executes the script, bypassing application control policies due to its signed status.\u003c/li\u003e\n\u003cli\u003eThe script establishes a network connection to an external command and control (C2) server.\u003c/li\u003e\n\u003cli\u003eThe C2 server provides instructions to the compromised host, such as downloading additional malware.\u003c/li\u003e\n\u003cli\u003eThe downloaded malware executes, performing actions such as data exfiltration or lateral movement.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the compromised host to move laterally within the network, compromising additional systems.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as stealing sensitive 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 execution of arbitrary code, potentially compromising sensitive data, facilitating lateral movement, and establishing a persistent presence within the network. Systems affected by this activity may be used as a beachhead for further attacks, leading to significant data breaches, financial loss, and reputational damage. The number of victims 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 process creation logging to capture the command-line arguments used by Mshta.exe.\u003c/li\u003e\n\u003cli\u003eDeploy the \u0026ldquo;Mshta Network Connection\u0026rdquo; Sigma rule to your SIEM and tune for your environment.\u003c/li\u003e\n\u003cli\u003eImplement application whitelisting to prevent unauthorized execution of Mshta.exe and similar system binaries.\u003c/li\u003e\n\u003cli\u003eMonitor network connections initiated by Mshta.exe, including destination IP addresses, domains, and ports, to identify any connections to known malicious or suspicious endpoints.\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-mshta-network-connections/","summary":"Mshta.exe making outbound network connections may indicate adversarial activity, as it is often used to execute malicious scripts and evade detection by proxying execution of untrusted code.","title":"Mshta Making Network Connections Indicative of Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-mshta-network-connections/"},{"_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":["Elastic Defend","SentinelOne Cloud Funnel","Sysmon"],"_cs_severities":["low"],"_cs_tags":["lolbin","defense-evasion","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic"],"content_html":"\u003cp\u003eAttackers may leverage LOLBINs, signed binaries that are part of the operating system, to perform malicious actions while blending in with legitimate system activity. This technique allows them to evade detection by application allowlists and signature validation. This brief focuses on the abuse of expand.exe, extrac32.exe, ieexec.exe, and makecab.exe to initiate outbound network connections. The LOLBINs are used to execute malicious code, download additional payloads, or establish command and control channels. This activity can be indicative of malware installation, data exfiltration, or other malicious post-exploitation activities. Detection is crucial to identify potentially compromised systems and prevent further damage.\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 (e.g., through phishing or exploitation of a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker executes a signed LOLBIN, such as \u003ccode\u003eexpand.exe\u003c/code\u003e, \u003ccode\u003eextrac32.exe\u003c/code\u003e, \u003ccode\u003eieexec.exe\u003c/code\u003e, or \u003ccode\u003emakecab.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe LOLBIN is used to download or execute a malicious payload from a remote server.\u003c/li\u003e\n\u003cli\u003eThe executed binary establishes a network connection to an external IP address.\u003c/li\u003e\n\u003cli\u003eData exfiltration may occur over the established network connection.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistence on the system by scheduling tasks or modifying registry keys.\u003c/li\u003e\n\u003cli\u003eThe attacker moves laterally within the network, compromising additional systems.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eA successful attack leveraging LOLBINs can result in the installation of malware, data theft, or full system compromise. The use of signed binaries makes it more difficult to detect malicious activity, potentially allowing attackers to operate undetected for extended periods. The financial and reputational damage caused by such attacks can be significant. While the risk score is low, the potential for defense evasion justifies monitoring.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eImplement the provided Sigma rule \u003ccode\u003eNetwork Connection via Signed Binary\u003c/code\u003e to detect suspicious network connections initiated by LOLBINs.\u003c/li\u003e\n\u003cli\u003eMonitor process execution logs for instances of \u003ccode\u003eexpand.exe\u003c/code\u003e, \u003ccode\u003eextrac32.exe\u003c/code\u003e, \u003ccode\u003eieexec.exe\u003c/code\u003e, and \u003ccode\u003emakecab.exe\u003c/code\u003e using process creation logging.\u003c/li\u003e\n\u003cli\u003eReview network connection logs for outbound connections initiated by these processes, excluding connections to internal networks based on the provided list of private IP ranges.\u003c/li\u003e\n\u003cli\u003eInvestigate any detected instances of LOLBINs making external network connections, correlating with other suspicious activities on the affected host, as detailed in the \u0026ldquo;Triage and analysis\u0026rdquo; 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-lolbin-network-connection/","summary":"Adversaries can use Living-Off-The-Land Binaries (LOLBINs) such as expand.exe, extrac32.exe, ieexec.exe, and makecab.exe to establish network connections, potentially bypassing security controls and facilitating malicious activities on Windows systems.","title":"LOLBIN Network Connection for Defense Evasion","url":"https://feed.craftedsignal.io/briefs/2024-01-lolbin-network-connection/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","SentinelOne Cloud Funnel"],"_cs_severities":["medium"],"_cs_tags":["lateral-movement","windows","winrm","remote-execution"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne"],"content_html":"\u003cp\u003eWindows Remote Management (WinRM) is a protocol that allows for remote management and execution of commands on Windows machines. While beneficial for legitimate administrative tasks, adversaries can exploit WinRM for lateral movement by executing commands remotely. This detection rule identifies suspicious activity by monitoring network traffic on specific ports and processes initiated by WinRM (winrshost.exe), flagging potential unauthorized remote executions. The rule is designed for data generated by Elastic Defend, but also supports SentinelOne Cloud Funnel and Sysmon event logs. This detection can help identify attackers moving laterally within a Windows environment.\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 machine within the network (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uses this compromised machine to scan the network for potential targets with WinRM enabled.\u003c/li\u003e\n\u003cli\u003eThe attacker attempts to authenticate to a target machine using stolen credentials or by exploiting a vulnerability in WinRM.\u003c/li\u003e\n\u003cli\u003eUpon successful authentication, the attacker establishes a WinRM session to the target machine over ports 5985 (HTTP) or 5986 (HTTPS).\u003c/li\u003e\n\u003cli\u003eThe attacker executes malicious commands on the target machine using the WinRM remote shell, often leveraging \u003ccode\u003ewinrshost.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe executed commands may include reconnaissance activities (e.g., \u003ccode\u003ewhoami\u003c/code\u003e, \u003ccode\u003enet user\u003c/code\u003e), privilege escalation attempts, or malware deployment.\u003c/li\u003e\n\u003cli\u003eThe attacker may use the compromised target to pivot to other systems, repeating the process and expanding their foothold.\u003c/li\u003e\n\u003cli\u003eThe final objective is typically data exfiltration, system compromise, or deployment of ransomware.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation via WinRM can lead to unauthorized access to sensitive data, system compromise, and lateral movement within the network. Attackers can leverage WinRM to execute arbitrary commands, deploy malware, and ultimately achieve their objectives, such as data theft or ransomware deployment. The impact can range from individual system compromise to widespread network breaches, depending on the attacker\u0026rsquo;s goals and the organization\u0026rsquo;s security posture.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation (Event ID 1) and network connection (Event ID 3) logging to provide the necessary data for the Sigma rules.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Incoming WinRM Remote Shell Execution via Network Connection\u003c/code\u003e to identify suspicious network connections on ports 5985 and 5986.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Suspicious WinRM Processes\u003c/code\u003e to detect suspicious processes spawned by \u003ccode\u003ewinrshost.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eReview and whitelist known administrative IP addresses or users to reduce false positives as noted in the rule documentation.\u003c/li\u003e\n\u003cli\u003eImplement network segmentation to limit the ability of threats to move laterally across the network as described in the remediation steps.\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-winrm-lateral-movement/","summary":"This rule detects incoming execution via Windows Remote Management (WinRM) remote shell on a target host, which could be an indication of lateral movement by monitoring network traffic on ports 5985 or 5986 and processes initiated by WinRM.","title":"Incoming Execution via WinRM Remote Shell","url":"https://feed.craftedsignal.io/briefs/2024-01-winrm-lateral-movement/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","SentinelOne Cloud Funnel","Windows Subsystem for Linux"],"_cs_severities":["medium"],"_cs_tags":["defense-evasion","windows","wsl"],"_cs_type":"advisory","_cs_vendors":["Elastic","Microsoft","SentinelOne"],"content_html":"\u003cp\u003eThe Windows Subsystem for Linux (WSL) allows users to run a Linux environment directly on Windows. Adversaries may exploit WSL to modify host files stealthily, bypassing traditional security measures and evading detection. This can be achieved by using WSL processes, especially those involving the Plan9FileSystem, to perform file operations on the host system. The detection rule identifies suspicious file operations initiated by \u003ccode\u003edllhost.exe\u003c/code\u003e with the Plan9FileSystem CLSID \u0026ldquo;{DFB65C4C-B34F-435D-AFE9-A86218684AA8}\u0026rdquo; to flag potential defense evasion attempts. This technique can be employed to modify system configurations, plant malicious files, or exfiltrate sensitive data, while blending in with legitimate WSL usage. Elastic has observed this activity and published a detection rule to identify such events.\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\u003eWSL is enabled on the target system, if not already enabled.\u003c/li\u003e\n\u003cli\u003eThe attacker executes commands within the WSL environment.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003edllhost.exe\u003c/code\u003e is spawned to facilitate file system operations between WSL and the host.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the Plan9FileSystem to interact with the Windows host file system.\u003c/li\u003e\n\u003cli\u003eMalicious files are created or existing files are modified on the host system using \u003ccode\u003edllhost.exe\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThese files may be placed in locations outside of typical user directories to avoid detection.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as data theft or further system compromise, using the modified files or configurations.\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 sensitive data, modification of critical system files, and the installation of malware on the Windows host. While the exact number of victims and sectors targeted are not specified, this technique allows attackers to bypass traditional security measures, making it difficult to detect malicious activity. The impact could range from data breaches to complete system compromise, depending on the attacker\u0026rsquo;s objectives.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable Sysmon process creation and file creation logging to capture the execution of \u003ccode\u003edllhost.exe\u003c/code\u003e and file modifications (Sysmon Event ID 1 and 11).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Host File System Changes via Windows Subsystem for Linux\u0026rdquo; to your SIEM to detect suspicious file operations involving \u003ccode\u003edllhost.exe\u003c/code\u003e and the Plan9FileSystem CLSID.\u003c/li\u003e\n\u003cli\u003eExclude legitimate WSL development directories and processes from the detection rule to reduce false positives.\u003c/li\u003e\n\u003cli\u003eMonitor for processes and file operations involving \u003ccode\u003edllhost.exe\u003c/code\u003e and the Plan9FileSystem, alerting on unusual activity.\u003c/li\u003e\n\u003cli\u003eReview and whitelist legitimate applications using WSL that may trigger alerts to prevent unnecessary notifications.\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-filesystem-modification/","summary":"This rule detects file creation and modification on the host system from the Windows Subsystem for Linux (WSL), potentially indicating defense evasion by adversaries.","title":"Host File System Changes via Windows Subsystem for Linux","url":"https://feed.craftedsignal.io/briefs/2024-01-wsl-filesystem-modification/"},{"_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":["M365 Defender","Elastic Defend","CrowdStrike FDR","SentinelOne Cloud Funnel","Sysmon"],"_cs_severities":["medium"],"_cs_tags":["execution","defense-evasion","dll-hijacking"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Crowdstrike","SentinelOne","Elastic"],"content_html":"\u003cp\u003eThis detection identifies potential abuse of the Windows Side-by-Side (SxS) feature to execute malicious code. Attackers can place a malicious DLL file within an application\u0026rsquo;s local SxS folder (application.exe.local) and trick the Windows module loader into prioritizing it over legitimate system DLLs. This technique, known as DLL hijacking or DLL redirection, allows adversaries to gain arbitrary code execution within the context of the targeted application. This technique may be used to bypass security controls, escalate privileges, or establish persistence. The detection focuses on file events related to DLLs within these specific SxS folders.\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 identifies a legitimate application with an associated SxS folder (application.exe.local).\u003c/li\u003e\n\u003cli\u003eThe attacker creates or modifies a malicious DLL file.\u003c/li\u003e\n\u003cli\u003eThe attacker places the malicious DLL file in the application\u0026rsquo;s SxS folder (application.exe.local).\u003c/li\u003e\n\u003cli\u003eA legitimate application attempts to load a DLL.\u003c/li\u003e\n\u003cli\u003eDue to the presence of the malicious DLL in the SxS folder, the Windows module loader prioritizes the attacker\u0026rsquo;s DLL.\u003c/li\u003e\n\u003cli\u003eThe malicious DLL is loaded and executed by the application.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves code execution within the context of the application.\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 within the targeted application\u0026rsquo;s context. This can result in privilege escalation, data theft, system compromise, or the establishment of persistence mechanisms. While the number of directly affected organizations is unknown, this technique can be used against a wide range of applications on Windows systems.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor file creation events for DLL files in \u003ccode\u003eC:\\*\\*.exe.local\\*.dll\u003c/code\u003e and \u003ccode\u003e\\\\Device\\\\HarddiskVolume*\\\\*\\\\*.exe.local\\\\*.dll\u003c/code\u003e using the provided Sigma rule to detect potential malicious DLL planting.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon Event ID 11 (File Create) to improve visibility into file creation events, as noted in the \u003ca href=\"https://ela.st/sysmon-event-11-setup\"\u003esetup instructions\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule to determine the legitimacy of the DLL creation event and the involved application.\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-local-sxs-dll-execution/","summary":"This rule detects the creation, modification, or deletion of DLL files within Windows SxS local folders, which could indicate an attempt to execute malicious payloads by abusing shared module loading.","title":"Execution via Local SxS Shared Module","url":"https://feed.craftedsignal.io/briefs/2024-01-03-local-sxs-dll-execution/"},{"_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/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Microsoft Defender XDR","Sysmon","Elastic Endgame","Elastic Defend","SentinelOne Cloud Funnel","Crowdstrike"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","command-line","unicode","obfuscation"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Elastic","SentinelOne","Crowdstrike"],"content_html":"\u003cp\u003eAttackers are increasingly employing Unicode modifier letters to obfuscate command-line arguments, thereby bypassing traditional string-based detection mechanisms. This technique involves replacing standard ASCII characters with visually similar Unicode characters, making it difficult for simple pattern-matching rules to identify malicious commands. The obfuscation targets common Windows utilities such as \u003ccode\u003ereg.exe\u003c/code\u003e, \u003ccode\u003enet.exe\u003c/code\u003e, \u003ccode\u003ecertutil.exe\u003c/code\u003e, \u003ccode\u003ePowerShell.exe\u003c/code\u003e, \u003ccode\u003ecmd.exe\u003c/code\u003e, and others frequently abused in post-exploitation scenarios. Defenders need to implement more sophisticated detection methods that account for Unicode normalization or character range analysis to identify and mitigate this threat. This technique has become more prevalent in the last year as attackers seek to evade common detection strategies.\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, potentially through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eExecution: The attacker executes a command-line utility like \u003ccode\u003ecmd.exe\u003c/code\u003e or \u003ccode\u003epowershell.exe\u003c/code\u003e to perform malicious actions.\u003c/li\u003e\n\u003cli\u003eObfuscation: The command-line arguments are obfuscated by replacing ASCII characters with Unicode modifier letters.\u003c/li\u003e\n\u003cli\u003eDefense Evasion: The obfuscation allows the attacker to evade simple string-based detections that would normally flag the command as malicious.\u003c/li\u003e\n\u003cli\u003ePrivilege Escalation: The attacker may use the obfuscated command to escalate privileges or gain access to sensitive resources.\u003c/li\u003e\n\u003cli\u003ePersistence: The attacker may establish persistence by creating a scheduled task or modifying the registry using obfuscated commands.\u003c/li\u003e\n\u003cli\u003eLateral Movement: The attacker may use the obfuscated command to move laterally to other systems on the network.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful command obfuscation can lead to a significant compromise of Windows systems. Attackers can bypass security controls and execute malicious code undetected, potentially leading to data theft, system disruption, or ransomware deployment. The obfuscation makes it harder for security teams to identify and respond to attacks, increasing the dwell time and potential damage.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule provided below to detect the presence of Unicode modifier letters in command lines (references: Sigma rules).\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture command-line arguments for analysis (references: Sysmon setup instructions).\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts triggered by the Sigma rule and analyze the raw command lines to identify the true intent of the command (references: Triage and Analysis section of the source).\u003c/li\u003e\n\u003cli\u003eConsider implementing Unicode normalization techniques to remove the obfuscation before analyzing command lines.\u003c/li\u003e\n\u003cli\u003eMonitor the listed processes (\u003ccode\u003ereg.exe\u003c/code\u003e, \u003ccode\u003enet.exe\u003c/code\u003e, \u003ccode\u003ecertutil.exe\u003c/code\u003e, etc.) more closely 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-unicode-cmd-obfuscation/","summary":"Adversaries use Unicode modifier letters to obfuscate command-line arguments, evading string-based detections on common Windows utilities like PowerShell and cmd.exe.","title":"Command Obfuscation via Unicode Modifier Letters","url":"https://feed.craftedsignal.io/briefs/2024-01-unicode-cmd-obfuscation/"}],"language":"en","next_url":"/products/sentinelone-cloud-funnel/page/2/feed.json","title":"CraftedSignal Threat Feed — SentinelOne Cloud Funnel","version":"https://jsonfeed.org/version/1.1"}