huntrule

Windows Process Creation: wlrmdr.exe with -u Flag or Uncommon Child Process Execution

Flags wlrmdr.exe launched with -u or uncommon children spawned with specific flags, using process creation telemetry.

FreeReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
frack113, manasmbellani (SigmaHQ), DRL 1.1
Published
2022-02-16
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 identifies executions where wlrmdr.exe is launched with the -u command-line flag, which can pass attacker-controlled values to ShellExecute. It also flags cases where wlrmdr.exe spawns child processes using a set of uncommon argument flags, excluding events where the parent is winlogon.exe, empty, or null. The detection relies on Windows process creation telemetry including ParentImage, Image/OriginalFileName, and CommandLine contents.

Reporting behind it

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Windows Process Creation: wlrmdr.exe with -u Flag or Uncommon Child Process Execution
Pivot detection · T1218 · 9 related

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