Execution of Powershell Script in Public Folder — Sigma Rule

Rule metadata and linked tags

Author: Max Altgelt (Nextron Systems). Source status: test; severity: high. Source dates: 2022-04-06 / 2022-07-14.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 2d09260a64eba1cca6711e41cc8a7a8bab44a317496f2912b84f273fe55704cd

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Execution of Powershell Script in Public Folder
id: fb9d3ff7-7348-46ab-af8c-b55f5fbf39b4
status: test
description: This rule detects execution of PowerShell scripts located in the "C:\Users\Public" folder
references:
    - https://www.mandiant.com/resources/evolution-of-fin7
author: Max Altgelt (Nextron Systems)
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

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://www.mandiant.com/resources/evolution-of-fin7