{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/xworm/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Splunk Enterprise","Splunk Enterprise Security","Splunk Cloud"],"_cs_severities":["high"],"_cs_tags":["powershell","cryptography","malware","asyncrat","xworm","vip keylogger"],"_cs_type":"advisory","_cs_vendors":["Splunk"],"content_html":"\u003cp\u003eThis threat brief focuses on detecting suspicious PowerShell activity involving the System.Security.Cryptography namespace, excluding common hashing algorithms like SHA and MD5. The detection leverages Windows PowerShell Script Block Logging (EventCode 4104) to identify scripts using cryptographic functions. This is significant because malware often uses cryptography to decrypt or decode additional malicious payloads, which can lead to further code execution, privilege escalation, or persistence within the compromised environment. The technique is commonly used by malware families like AsyncRAT, XWorm, and VIP Keylogger. Defenders should investigate the parent process of such scripts, the decrypted data, network connections established by the script, and the user context in which the script is executed.\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 executes a PowerShell script on the compromised system.\u003c/li\u003e\n\u003cli\u003eThe PowerShell script utilizes the \u003ccode\u003eSystem.Security.Cryptography\u003c/code\u003e namespace to perform cryptographic operations.\u003c/li\u003e\n\u003cli\u003eThe script decrypts or decodes a malicious payload (e.g., a second-stage executable or configuration file).\u003c/li\u003e\n\u003cli\u003eThe decrypted payload is written to disk or loaded directly into memory.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the decrypted payload, potentially establishing persistence via registry keys or scheduled tasks.\u003c/li\u003e\n\u003cli\u003eThe malware leverages the established persistence mechanism for long-term access.\u003c/li\u003e\n\u003cli\u003eThe attacker performs malicious actions such as data exfiltration, lateral movement, or remote command execution.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation allows attackers to bypass security measures by hiding malicious code within encrypted payloads. This can lead to data theft, system compromise, and further propagation within the network. Malware families like AsyncRAT, XWorm, and VIP Keylogger use this technique to maintain persistence and perform malicious activities undetected. The impact can range from individual workstation compromise to large-scale data breaches depending on the attacker\u0026rsquo;s objectives and the compromised system\u0026rsquo;s role within the organization.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eEnable PowerShell Script Block Logging on all endpoints to generate the necessary logs (EventCode 4104) for detection.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Suspicious PowerShell Cryptography Namespace Usage\u003c/code\u003e to your SIEM to detect the described activity.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by the Sigma rule by examining the parent process, decrypted data, network connections, and the user executing the script.\u003c/li\u003e\n\u003cli\u003eReview and tune the Sigma rule \u003ccode\u003eDetect Suspicious PowerShell Cryptography Namespace Usage\u003c/code\u003e based on your environment\u0026rsquo;s specific needs and known-good PowerShell usage to reduce false positives.\u003c/li\u003e\n\u003cli\u003eImplement application control policies to restrict the execution of unsigned or untrusted PowerShell scripts.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T18:00:00Z","date_published":"2024-01-03T18:00:00Z","id":"/briefs/2024-01-powershell-cryptography/","summary":"The analytic detects suspicious PowerShell script execution involving the cryptography namespace (excluding SHA and MD5) via EventCode 4104, often associated with malware that decrypts or decodes additional malicious payloads leading to further code execution, privilege escalation, or persistence.","title":"Suspicious PowerShell Script Using Cryptography Namespace","url":"https://feed.craftedsignal.io/briefs/2024-01-powershell-cryptography/"}],"language":"en","title":"CraftedSignal Threat Feed — Xworm","version":"https://jsonfeed.org/version/1.1"}