{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/scripting-interpreter/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Elastic Endpoint"],"_cs_severities":["high"],"_cs_tags":["defense-evasion","execution","scripting-interpreter","base64","command-line"],"_cs_type":"advisory","_cs_vendors":["Elastic"],"content_html":"\u003cp\u003eThis rule identifies the execution of scripting interpreters (Python, PowerShell, Node.js, and Deno) with unusually long command lines containing base64 encoded payloads. The rule focuses on scenarios where the initial \u003ccode\u003eprocess.command_line\u003c/code\u003e field is ignored due to its excessive length, but the complete command line is still available in \u003ccode\u003eprocess.command_line.text\u003c/code\u003e. Attackers leverage this technique to evade traditional command-line inspection and execute malicious content across Windows, macOS, and Linux systems. This approach allows attackers to embed and execute code without writing it to disk, making it harder to detect. The rule is designed to detect this behavior, allowing for closer inspection of the executed commands and their intent.\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 (e.g., via phishing or exploiting a vulnerability).\u003c/li\u003e\n\u003cli\u003eThe attacker uses PowerShell, Python, Node.js, or Deno to execute commands.\u003c/li\u003e\n\u003cli\u003eA long, base64-encoded string is crafted, designed to evade detection.\u003c/li\u003e\n\u003cli\u003eThe interpreter is invoked with the encoded string passed as an argument, exceeding typical command-line limits.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003eprocess.command_line\u003c/code\u003e field is truncated due to its length, but the full command line is available in \u003ccode\u003eprocess.command_line.text\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe interpreter decodes and executes the payload from the \u003ccode\u003eprocess.command_line.text\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe decoded payload performs malicious actions such as downloading malware, establishing persistence, or exfiltrating data.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves their objective, such as gaining control of the system or stealing sensitive information.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation can lead to a wide range of malicious activities, including malware installation, data theft, privilege escalation, and system compromise. Due to the defense evasion capabilities, it is difficult to identify and prevent. The impact includes potential data breaches, financial losses, and reputational damage. The rule\u0026rsquo;s detection helps defenders identify this attack vector and prevent further exploitation of affected systems.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Long Base64 Encoded Command via Scripting Interpreter\u003c/code\u003e to your SIEM to detect this behavior.\u003c/li\u003e\n\u003cli\u003eInvestigate any alerts generated by this rule, focusing on the \u003ccode\u003eprocess.command_line.text\u003c/code\u003e field to understand the full command being executed.\u003c/li\u003e\n\u003cli\u003eReview parent processes and execution chains of the interpreter to understand the initial attack vector.\u003c/li\u003e\n\u003cli\u003eImplement controls to restrict the execution of scripting interpreters from untrusted sources.\u003c/li\u003e\n\u003cli\u003eMonitor process execution logs for command lines exceeding a certain length threshold.\u003c/li\u003e\n\u003cli\u003eImprove logging coverage to capture the full command line even when it exceeds standard limits.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-03T17:00:00Z","date_published":"2024-01-03T17:00:00Z","id":"/briefs/2024-01-03-long-base64-interpreter-cmdline/","summary":"Detection of oversized command lines used by Python, PowerShell, Node.js, or Deno interpreters containing base64 decoding or encoded-command patterns, indicating potential evasion and malicious execution.","title":"Long Base64 Encoded Command via Scripting Interpreter","url":"https://feed.craftedsignal.io/briefs/2024-01-03-long-base64-interpreter-cmdline/"}],"language":"en","title":"CraftedSignal Threat Feed — Scripting-Interpreter","version":"https://jsonfeed.org/version/1.1"}