Windows PowerShell Token Obfuscation via Process Command Line

title: Windows PowerShell Token Obfuscation via Process Command Line
id: f4ba6f80-92bc-400e-b1ba-ac827d5626a1
related:
  - id: f3a98ce4-6164-4dd4-867c-4d83de7eca51
    type: similar
  - id: deb9b646-a508-44ee-b7c9-d8965921c6b6
    type: derived
status: test
description: This rule flags Windows process creation events where the command line contains patterns consistent with PowerShell token obfuscation as used by Invoke-Obfuscation. Attackers use this behavior to evade signature-based detection by fragmenting or encoding keywords and expressions. The detection relies on process creation telemetry, specifically the process command line, and applies a filter to reduce matches involving ${env:path}.
references:
  - https://github.com/danielbohannon/Invoke-Obfuscation
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_powershell_token_obfuscation.yml
author: frack113, Huntrule Team
date: 2022-12-27
modified: 2026-03-16
tags:
  - attack.stealth
  - attack.t1027.009
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    - CommandLine|re: \w+`(?:\w+|-|.)`[\w+|\s]
    - CommandLine|re: '"(?:\{\d\})+"\s*-f'
    - CommandLine|re: (?i)\$\{`?e`?n`?v`?:`?p`?a`?t`?h`?\}
  filter_main_envpath:
    CommandLine|contains: ${env:path}
  condition: selection and not 1 of filter_main_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1