huntrule

Windows: Suspicious userinit.exe Child Process Creation

Alerts when userinit.exe spawns an atypical child process, excluding known benign explorer and netlogon command-line patterns.

FreeReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
Florian Roth (Nextron Systems), Samir Bousseaden (idea) (SigmaHQ), DRL 1.1
Published
2019-06-17
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 userinit.exe and the child process command line does not match common benign patterns. Attackers may abuse userinit to spawn unexpected processes for privilege escalation or stealthy execution during user logon. It relies on Windows process creation telemetry, including parent image path and child command-line content, to identify unusual child process relationships.

Reporting behind it

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FlawedGrace spawning threat injection target
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Windows: Suspicious userinit.exe Child Process Creation
Pivot detection · T1055 · 9 related

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