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Windows File Drops Matching Winnti Dropper Artifacts (gthread/sigcmm DLLs, tmp.bat)

Detects Windows file drops of specific DLLs and a Windows Temp batch filename pattern associated with a Winnti dropper scenario.

FreeReviewedSigma · High · v2
Product
windows
Category
file_event
Author
Alexander Rausch (SigmaHQ), DRL 1.1
Published
2020-06-24
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Defense Evasion

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags Windows file creation events where filenames end with specific Winnti dropper artifacts: gthread-3.6.dll, sigcmm-2.4.dll, or a temporary batch file path ending with \Windows\Temp\tmp.bat. Such targeted drops are indicative of malware staging or execution preparation on a host. The detection relies on file event telemetry that includes the created or written file path and supports suffix matching on the target filename.

Reporting behind it

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Suspicious PS1Bot PowerShell Payload Written to ProgramData (via file_event)
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Windows File Drops Matching Winnti Dropper Artifacts (gthread/sigcmm DLLs, tmp.bat)
Pivot detection · T1027 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. v1
    No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.