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Windows UAC Bypass via Disk Cleanup cleanmgr.exe run from Scheduled Task

Flags scheduled-task executions of cleanmgr.exe with disk-cleanup parameters running at high/System integrity.

FreeReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
Christian Burkard (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2021-08-30
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 matches Windows process creation where cleanmgr.exe is launched with specific arguments for disk cleanup and is executed under elevated integrity. It also correlates the parent process to the Task Scheduler service host (svchost.exe running the Schedule service), which is consistent with UAC bypass techniques that rely on trusted system components. Detection relies on process creation telemetry, including command line content, parent command line, and integrity level values.

Reporting behind it

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Malicious UAC Bypass via explorer.exe NOUACCHECK Argument
Suspicious UAC Bypass via ms-settings Shell Command Hijack (via registry_set)
Windows UAC Bypass via Disk Cleanup cleanmgr.exe run from Scheduled Task
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.