Windows PowerShell execution from C:\Users\Public

title: Windows PowerShell execution from C:\Users\Public
id: 0c047195-2789-4fab-89bb-c8281b858b8a
status: test
description: This rule identifies process creation where PowerShell (powershell.exe or pwsh.exe) is invoked with arguments pointing to scripts or content located in C:\Users\Public. Attackers may use this common writable public directory to stage files and then execute them to run code with the user’s context. The detection relies on Windows process creation telemetry, matching the PowerShell binary name and specific command-line substrings referencing C:\Users\Public and related flags.
references:
  - https://www.mandiant.com/resources/evolution-of-fin7
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_powershell_public_folder.yml
author: Max Altgelt (Nextron Systems), Huntrule Team
date: 2022-04-06
modified: 2022-07-14
tags:
  - attack.execution
  - attack.t1059.001
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - \powershell.exe
      - \pwsh.exe
    CommandLine|contains:
      - -f C:\Users\Public
      - -f "C:\Users\Public
      - -f %Public%
      - -fi C:\Users\Public
      - -fi "C:\Users\Public
      - -fi %Public%
      - -fil C:\Users\Public
      - -fil "C:\Users\Public
      - -fil %Public%
      - -file C:\Users\Public
      - -file "C:\Users\Public
      - -file %Public%
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: fb9d3ff7-7348-46ab-af8c-b55f5fbf39b4
    type: derived