{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/products/brave/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["OneDrive","Chrome","Brave","Opera","Discord","Slack","Microsoft 365","SharePoint"],"_cs_severities":["medium"],"_cs_tags":["command-and-control","windows","threat-detection"],"_cs_type":"advisory","_cs_vendors":["Microsoft","Google","Brave Software","Opera","Discord","Slack"],"content_html":"\u003cp\u003eAdversaries may implement command and control (C2) communications that use common web services to hide their activity. This attack technique is typically targeted at an organization and uses web services common to the victim network, which allows the adversary to blend into legitimate traffic activity. These popular services are typically targeted since they have most likely been used before compromise, which helps malicious traffic blend in. This detection focuses on identifying connections from Windows hosts to a predefined list of commonly abused web services from processes running outside of typical program installation directories, indicating a potential C2 channel leveraging legitimate services. The rule aims to detect this behavior by monitoring network connections and DNS requests originating from unusual locations.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eInitial access is achieved via an unknown method (e.g., phishing, exploit).\u003c/li\u003e\n\u003cli\u003eMalware is installed on the victim\u0026rsquo;s system, likely outside typical program directories.\u003c/li\u003e\n\u003cli\u003eThe malware establishes a DNS connection to a commonly abused web service (e.g., pastebin.com, raw.githubusercontent.com) to obscure C2 traffic.\u003c/li\u003e\n\u003cli\u003eThe malware sends encrypted or encoded commands to the web service.\u003c/li\u003e\n\u003cli\u003eThe web service acts as an intermediary, relaying the commands to the attacker\u0026rsquo;s C2 server.\u003c/li\u003e\n\u003cli\u003eThe C2 server responds with instructions, which are then relayed back to the compromised host through the same web service.\u003c/li\u003e\n\u003cli\u003eThe malware executes the received commands, potentially leading to data exfiltration, lateral movement, or other malicious activities.\u003c/li\u003e\n\u003cli\u003eThe attacker maintains persistent access and control over the compromised system using the web service as a hidden C2 channel.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to data theft, system compromise, and further propagation within the network. Since commonly used web services are utilized, the malicious activity can blend in with legitimate network traffic, making it difficult to detect. The impact can range from minor data breaches to complete network compromise, depending on the attacker\u0026rsquo;s objectives and the level of access gained.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Commonly Abused Web Services via DNS\u003c/code\u003e to your SIEM to identify suspicious DNS queries to known C2 web services originating from anomalous processes.\u003c/li\u003e\n\u003cli\u003eEnable DNS query logging on Windows endpoints to provide the data source required for the Sigma rule.\u003c/li\u003e\n\u003cli\u003eReview network connection logs for processes outside standard installation directories communicating with domains listed in the \u003ccode\u003equery\u003c/code\u003e section of the Sigma rule to identify potential C2 activity.\u003c/li\u003e\n\u003cli\u003eImplement network segmentation to limit the potential impact of compromised hosts.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-04T12:00:00Z","date_published":"2024-01-04T12:00:00Z","id":"/briefs/2024-01-04-c2-web-services/","summary":"This rule detects command and control activity using common web services by identifying Windows hosts making DNS requests to a list of commonly abused web services from processes outside of known program locations, potentially indicating adversaries attempting to blend malicious traffic with legitimate network activity.","title":"Detection of Command and Control Activity via Commonly Abused Web Services","url":"https://feed.craftedsignal.io/briefs/2024-01-04-c2-web-services/"},{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Defend","Slack","WebEx","Teams","Discord","WhatsApp","Zoom","Outlook","Thunderbird","Grammarly","Dropbox","Tableau","Google Drive","MSOffice","Okta","OneDrive","Chrome","Firefox","Edge","Brave","GoogleCloud Related Tools","Github Related Tools","Notion"],"_cs_severities":["medium"],"_cs_tags":["masquerading","defense-evasion","initial-access","malware","windows"],"_cs_type":"advisory","_cs_vendors":["Elastic","Slack","Cisco","Microsoft","Discord","Zoom","Mozilla","Grammarly","Dropbox","Tableau","Google","Okta","Brave","GitHub","Notion"],"content_html":"\u003cp\u003eAttackers often attempt to trick users into downloading and executing malicious executables by disguising them as legitimate business applications. This tactic is used to bypass security measures and gain initial access to a system. These malicious executables, often distributed via malicious ads, forum posts, and tutorials, mimic the names of commonly used applications such as Slack, WebEx, Teams, Discord, and Zoom. The executables are typically unsigned or signed with invalid certificates to further evade detection. This allows the attacker to execute arbitrary code on the victim\u0026rsquo;s machine, potentially leading to further compromise. This campaign aims to target end-users who are less security-aware, and this makes social engineering attacks like this very effective.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe user visits a compromised website or clicks on a malicious advertisement.\u003c/li\u003e\n\u003cli\u003eThe user is prompted to download an installer file masquerading as a legitimate business application (e.g., Slack, Zoom, Teams) from a download directory.\u003c/li\u003e\n\u003cli\u003eThe downloaded executable is placed in the user\u0026rsquo;s Downloads folder (e.g., C:\\Users*\\Downloads*).\u003c/li\u003e\n\u003cli\u003eThe user executes the downloaded file.\u003c/li\u003e\n\u003cli\u003eThe executable, lacking a valid code signature, begins execution.\u003c/li\u003e\n\u003cli\u003eThe malicious installer may drop and execute additional malware components.\u003c/li\u003e\n\u003cli\u003eThe malware establishes persistence, potentially using techniques such as registry key modification.\u003c/li\u003e\n\u003cli\u003eThe malware 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 execution of a masqueraded business application installer can lead to a complete system compromise. The attacker gains initial access and can deploy various malware payloads, including ransomware, keyloggers, and data stealers. This can result in data breaches, financial loss, and reputational damage. Although the specific number of victims and sectors targeted are not detailed, the widespread use of the applications being spoofed (Slack, Zoom, etc.) suggests a broad potential impact.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eImplement the Sigma rule \u003ccode\u003ePotential Masquerading as Business App Installer\u003c/code\u003e to detect unsigned executables resembling legitimate business applications in download directories.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging to capture the execution of unsigned executables.\u003c/li\u003e\n\u003cli\u003eEducate users on the risks of downloading and executing files from untrusted sources.\u003c/li\u003e\n\u003cli\u003eImplement application whitelisting to restrict the execution of unauthorized applications.\u003c/li\u003e\n\u003cli\u003eRegularly update endpoint detection and response (EDR) tools to detect and prevent the execution of known malware.\u003c/li\u003e\n\u003cli\u003eMonitor process execution events for processes originating from the Downloads folder that lack valid code signatures.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-02T12:00:00Z","date_published":"2024-01-02T12:00:00Z","id":"/briefs/2024-01-masquerading-business-apps/","summary":"Attackers masquerade malicious executables as legitimate business application installers to trick users into downloading and executing malware, leveraging defense evasion and initial access techniques.","title":"Masquerading Business Application Installers","url":"https://feed.craftedsignal.io/briefs/2024-01-masquerading-business-apps/"}],"language":"en","title":"CraftedSignal Threat Feed — Brave","version":"https://jsonfeed.org/version/1.1"}