Replace Desktop Wallpaper by Powershell — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: low. Source dates: 2021-12-26 / not supplied.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 66ead16a3b97a58d32f2c6e5acf2c3a0244e722abdb6b2c6f5d2c9d4b8a66048

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: Replace Desktop Wallpaper by Powershell
id: c5ac6a1e-9407-45f5-a0ce-ca9a0806a287
status: test
description: |
    An adversary may deface systems internal to an organization in an attempt to intimidate or mislead users.
    This may take the form of modifications to internal websites, or directly to user systems with the replacement of the desktop wallpaper
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1491.001/T1491.001.md
author: frack113
date: 2021-12-26
tags:
    - attack.impact
    - attack.t1491.001
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_1:
        ScriptBlockText|contains|all:
            - 'Get-ItemProperty'
            - 'Registry::'
            - 'HKEY_CURRENT_USER\Control Panel\Desktop\'
            - 'WallPaper'
    selection_2:
        ScriptBlockText|contains: SystemParametersInfo(20,0,*,3)
    condition: 1 of selection_*
falsepositives:
    - Unknown
level: low

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1491.001/T1491.001.md