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Windows CMSTP UAC Bypass Attempt via Autoelevate COM Object DllHost Execution

Detects DllHost.exe spawning CMSTP-related autoelevate COM objects by matching known Processid values and high/system integrity.

FreeReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
Nik Seetharaman, Christian Burkard (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2019-07-31
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

Priv Esc → 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 process creation events where the parent process is DllHost.exe with command lines that include specific COM Processid values tied to CMSTP-enabled autoelevate COM objects. UAC bypass techniques matter because they aim to obtain elevated execution without prompting the user. The detection relies on process creation telemetry, focusing on the parent image and parent command-line content plus high/system integrity levels.

Reporting behind it

Related detections9 linkedT1548.002 — drag to rearrange
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Suspicious UAC Bypass via control.exe App Paths or Shell Open Command Hijack
Malicious UAC Bypass via COMAutoApprovalList Registry Modification (via registry_set)
Suspicious UAC Bypass via COMAutoApprovalList Registry Modification (via registry_set)
Malicious UAC Bypass via explorer.exe NOUACCHECK Argument
Windows CMSTP UAC Bypass Attempt via Autoelevate COM Object DllHost Execution
Pivot detection · T1548.002 · 9 related

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