{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/payload-delivery/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Windows"],"_cs_severities":["high"],"_cs_tags":["attack.execution","attack.defense-evasion","csc.exe","payload-delivery"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eAttackers are leveraging the legitimate Csc.exe (C# compiler) to execute malicious code, often as a part of defense evasion or payload delivery. This is achieved by spawning Csc.exe from unusual parent processes such as scripting hosts (cscript.exe, wscript.exe), Office applications (excel.exe, winword.exe), or PowerShell, especially when combined with encoded commands. Observed techniques also include launching Csc.exe from temporary or unusual directories. This activity bypasses traditional application whitelisting and can lead to the execution of arbitrary code. This activity has been associated with WarzoneRAT, DarkVNC, and the delivery of IMAPLoader malware.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker gains initial access, potentially through phishing or exploiting a vulnerability.\u003c/li\u003e\n\u003cli\u003eA script or Office macro executes, initiating a command-line process.\u003c/li\u003e\n\u003cli\u003eThis process then invokes a scripting host (e.g., cscript.exe) or PowerShell.\u003c/li\u003e\n\u003cli\u003eThe scripting host or PowerShell executes a command that downloads or creates a C# source code file.\u003c/li\u003e\n\u003cli\u003eCsc.exe is then invoked, often from a temporary directory, to compile the downloaded/created C# code.\u003c/li\u003e\n\u003cli\u003eThe compiled C# code executes, performing malicious actions.\u003c/li\u003e\n\u003cli\u003eThe malicious code may establish persistence, communicate with a C2 server, or perform data exfiltration.\u003c/li\u003e\n\u003cli\u003eThe final objective might be to deploy ransomware, steal sensitive data, or establish a persistent backdoor.\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 systems, steal data, or deploy malware. Depending on the user\u0026rsquo;s permissions, the attacker could gain elevated privileges. The observed techniques have been associated with ransomware deployment, data theft, and remote access trojans (RATs).\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Csc.EXE Execution Form Potentially Suspicious Parent\u0026rdquo; to detect suspicious parent processes of csc.exe.\u003c/li\u003e\n\u003cli\u003eMonitor process creation events for csc.exe with parent processes like scripting hosts or Office applications.\u003c/li\u003e\n\u003cli\u003eInvestigate any instances of csc.exe being executed from temporary directories or user profile locations by reviewing process_creation logs.\u003c/li\u003e\n\u003cli\u003eEnable Sysmon process creation logging to capture detailed process information, including parent-child relationships, for effective detection.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2024-01-02T15:00:00Z","date_published":"2024-01-02T15:00:00Z","id":"/briefs/2024-01-02-csc-suspicious-parent/","summary":"The Csc.exe (C# compiler) process is being launched by unusual parent processes or from suspicious locations, indicating potential malware execution or defense evasion.","title":"Suspicious CSC.exe Parent Process","url":"https://feed.craftedsignal.io/briefs/2024-01-02-csc-suspicious-parent/"}],"language":"en","title":"CraftedSignal Threat Feed — Payload-Delivery","version":"https://jsonfeed.org/version/1.1"}