huntrule

Windows explorer.exe spawned with /NOUACCHECK flag for UAC bypass behavior

Alerts on explorer.exe executions that include /NOUACCHECK, indicating potential bypass of UAC checks for child processes.

FreeReviewedSigma · High · v2
Product
windows
Category
process_creation
Author
Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-02-23
Updated
2026-07-31
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

Identifies process creation events where explorer.exe is started with the /NOUACCHECK flag, which can allow child processes to run without UAC checks. Attackers may use this to bypass User Account Control protections during a staged execution via a newly spawned explorer instance. The rule relies on process creation telemetry including the image path and command-line arguments, and it excludes events where the parent command line matches a scheduled-task related svchost invocation.

Reporting behind it

Related detections9 linkedT1548.002 — drag to rearrange
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Malicious DBatLoader DLL Sideloading via easinvoker.exe Loading netutils.dll (via image_load)
Suspicious dllhost.exe Spawned with CLSID and Anomalous Parent (via process_creation)
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Malicious User Account Control Bypass via Auto-Elevating Binary Hijack (via process_creation)
Suspicious Mock Trusted Directory with Trailing Space (via process_creation)
Windows explorer.exe spawned with /NOUACCHECK flag for UAC bypass behavior
Pivot detection · T1548.002 · 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.