huntrule

PowerShell Module: Obfuscated Script Execution via Stdin Pattern

Detects obfuscated PowerShell module payloads using chained set and stdin/input invoke patterns.

FreeReviewedSigma · High · v2
Product
windows
Category
ps_module
Author
Nikita Nazarov, oscd.community (SigmaHQ), DRL 1.1
Published
2020-10-12
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Execution → 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 PowerShell module activity containing a string pattern consistent with obfuscated script execution that chains operations using "set" and then references environment/input execution constructs. Attackers often use this style to hinder static analysis and execute payloads indirectly through stdin-related input handling. The detection relies on telemetry fields that capture the PowerShell payload content and match it against the specified case-insensitive regular expression.

Reporting behind it

Related detections9 linkedT1027 — drag to rearrange
Suspicious PowerShell Invoke-Expression with Replace Obfuscation
Malicious Emmenhtal JavaScript Loader Spawning Encoded PowerShell
Suspicious Python Interpreter Launching Encoded PowerShell via subprocess
Suspicious PS1Bot PowerShell Payload Written to ProgramData (via file_event)
Malicious Non-Interactive Encoded PowerShell Stager (via process_creation)
Suspicious Hidden PowerShell Executing Substring of Dropped File
PowerShell Encoded or Download-Cradle Command Line (via process_creation)
Obfuscated Encoded PowerShell Payload Deployed - PowerShell (via powershell)
Suspicious PowerShell AES Decryption and Reflective Method Invocation in SolarMarker
PowerShell Module: Obfuscated Script Execution via Stdin Pattern
Pivot detection · T1027 · 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.