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Windows Process UAC Bypass via Windows Media Player osksupport.dll (osk.exe → cmd.exe)

Alerts on osk.exe spawning cmd.exe under mmc event viewer with high/system integrity, consistent with a UAC bypass attempt.

FreeReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
Christian Burkard (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2021-08-23
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 where Windows Media Player osk.exe is launched and a cmd.exe process appears with an mmc.exe parent that includes the event viewer snap-in. The combination of the specific executable path and high/system integrity targets behavior commonly associated with UAC bypass attempts. It relies on process creation telemetry capturing process Image, parent Image/command line, and the integrity level of the spawned process.

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
Suspicious UAC Bypass via ms-settings Shell Command Hijack (via registry_set)
Windows Process UAC Bypass via Windows Media Player osksupport.dll (osk.exe → cmd.exe)
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.