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Windows process creation: WerFault.exe executed with -pr flag

Alerts when WerFault.exe is launched with the -pr argument, potentially indicating ReflectDebugger-based execution.

FreeReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
X__Junior (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2023-06-30
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

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 executions of WerFault.exe where the process creation command line includes the " -pr " argument. The behavior matters because this flag is used to run a file path stored in the ReflectDebugger registry location, which attackers may abuse to masquerade execution flow. Telemetry required is Windows process creation data containing the executable name and the full command line (including original filename metadata).

Reporting behind it

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Windows process creation: WerFault.exe executed with -pr flag
Pivot detection · T1036 · 9 related

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