Suspicious Double Extension Executable Execution via Command Line

PremiumReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
HuntRule
Published
2026-09-21
Updated
2026-09-21

ATT&CK techniques

Persistence → Priv Esc
  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Defense Evasion

  6. Cred Access

  7. Discovery

  8. Lateral Movement

  9. Collection

  10. C2

  11. Exfiltration

  12. Impact

What it detects

This rule detects execution of a file with a doubled .exe.exe extension, a naming anomaly used by Parallax RAT for its startup executable to appear legitimate at a glance. No normal software ships a binary ending in .exe.exe. Detecting it exposes a disguised persistence dropper.

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Suspicious SystemBC Persistence via Run Key to ProgramData Script
Suspicious Interlock RAT Persistence via HKCU Run Key Registration to AppData Payload (via process_creation)
Suspicious Double Extension Executable Execution via Command Line
Pivot detection · T1547.001 · 9 related

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