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Windows Process Creation: Detect Reversed PowerShell Command Tokens in CommandLine

Alerts on suspicious reversed token usage in PowerShell command lines on Windows, excluding -EncodedCommand / -enc.

FreeReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
Teymur Kheirkhabarov (idea), Vasiliy Burov (rule), oscd.community, Tim Shelton (SigmaHQ), DRL 1.1
Published
2020-10-11
Updated
2026-07-30
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 Windows process creation events where PowerShell (powershell.exe or pwsh.exe) is launched with CommandLine content containing specific reversed-character tokens. Reversed strings are commonly used to obscure what the script is doing and may hinder straightforward command inspection. The detection relies on process creation telemetry and the Image and CommandLine fields, while excluding cases that include common encoded-command flags to reduce false positives.

Reporting behind it

Related detections9 linkedT1027 — drag to rearrange
Malicious FIN7 Powertrash Loader Execution via Obfuscated PowerShell (via process_creation)
Suspicious XOR Obfuscated PowerShell from ClickFix Distribution
Suspicious PowerShell Executing Code from Environment Variable (via process_creation)
Suspicious In-Memory Runspace Execution via PowerShell Script Block
Suspicious Encoded PowerShell Using Base64 Stream Decompression Routines (via process_creation)
Suspicious PowerShell In-Memory Execution with AES Decryption
Suspicious Encoded PowerShell Command Execution
Suspicious PEAKLIGHT Memory-Only PowerShell Downloader Flags (via process_creation)
Obfuscated PowerShell Script: Indirect Cmdlet Execution via ExportedCommands Array Index
Windows Process Creation: Detect Reversed PowerShell Command Tokens in CommandLine
Pivot detection · T1027 · 9 related

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