huntrule

Suspicious PowerShell EncodedCommand Spawned From Command Shell via Process Creation

PremiumReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
HuntRule
Published
2026-09-12
Updated
2026-09-12
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 cmd.exe spawning powershell.exe with an encoded command argument as seen in the KongTuke fake-CAPTCHA infection chain reported by Cisco Talos. Encoded PowerShell launched from a shell is used to run an in-memory downloader that pulls a second stage and beacons to attacker infrastructure. Catching this early breaks the chain before payload retrieval and anti-forensic cleanup occur.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange
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Malicious Emmenhtal JavaScript Loader Spawning Encoded PowerShell
Suspicious Python Interpreter Launching Encoded PowerShell via subprocess
Suspicious PowerShell Download of lib.zip Archive
Suspicious PowerShell Remote Payload Download via IEX DownloadString
Malicious PowerShell Spawned by PHP CGI Process
Suspicious PowerShell EncodedCommand Spawned From Command Shell via Process Creation
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.