huntrule

Suspicious PowerShell Encoded Command Execution

PremiumReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
HuntRule
Published
2026-11-03
Updated
2026-11-03
AnalysisDetection

ATT&CK techniques

Execution

  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 detects PowerShell being launched with an encoded command argument combined with a hidden window. In the WithSecure Initial Access Lab 1 attackers pass base64 encoded payloads through EncodedCommand to obscure the executed script. This flag combination is frequently used to conceal malicious commands from logging and analysts.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange
Malicious PowerShell Download Cradle With DownloadString
Suspicious PowerShell Hidden Download Cradle via IEX
Suspicious PowerShell IEX Execution of documentLoger Payload via CharmingCypress
Suspicious PowerShell WebClient DownloadString Payload Retrieval via Script (via ps_script)
Malicious PowerShell Executing Script From Public Directory via WScript
Suspicious PowerShell Executing Payload From Roaming AppData via Command Line (via process_creation)
Suspicious PowerShell Spawning mshta for Malware Execution (via process_creation)
Malicious SolarWinds BusinessLayerHost Spawning Suspicious Child Process (SUNBURST) (via process_creation)
Suspicious word_update.exe Spawning Command Shell in Remcos Chain (via process_creation)
Suspicious PowerShell Encoded Command Execution
Pivot detection · T1059.001 · 9 related

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