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HighSigmaHQ frack113 +3

Suspicious DotNET CLR Usage Log Artifact

Detects the creation of Usage Log files by the CLR (clr.dll). These files are named after the executing process once the assembly is finished executing for the first time in the (user) session context.

Detection logic

Detection requirements

Platform: Linux macOS Windows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
Log source product: windows
Log source category: file_event

Known benign triggers

Rundll32.exe with zzzzInvokeManagedCustomActionOutOfProc in command line and msiexec.exe as parent process - https://twitter.com/SBousseaden/status/1388064061087260675

References

Links the source published beside this detection. Reference is the link the source wrote, unmodified. Class is decided by this catalogue from the host and path, not stated by the source. Cited by counts published detections citing the same resource, including this one, and the sources beneath it count the repositories this catalogue ingests, which is not the same as independent research.
Reference	Class	Cited by
bohops.com/2021/03/16/investigating-net-clr-usage-log-tampering-techniques-for-edr-evasion/	Security research	2
github.com/olafhartong/sysmon-modular/blob/fa1ae53132403d262be2bbd7f17ceea7e15e8c78/11_file_create/include_dotnet.xml	Tool	Only this detection cites it
web.archive.org/web/20221026202428/https://gist.github.com/code-scrap/d7f152ffcdb3e0b02f7f394f5187f008	Unclassified	2
web.archive.org/web/20230329154538/https://blog.menasec.net/2019/07/interesting-difr-traces-of-net-clr.html	Unclassified	2

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