Modify Group Policy Settings

Detect malicious GPO modifications can be used to implement many other malicious behaviors.

Detection logic

selection_reg

- Image|endswith: \reg.exe
- OriginalFileName: reg.exe

selection_path

CommandLine|contains: \SOFTWARE\Policies\Microsoft\Windows\System

selection_key

CommandLine|contains:
  - GroupPolicyRefreshTimeDC
  - GroupPolicyRefreshTimeOffsetDC
  - GroupPolicyRefreshTime
  - GroupPolicyRefreshTimeOffset
  - EnableSmartScreen
  - ShellSmartScreenLevel

Condition

all of selection_*

Raw YAML

title: Modify Group Policy Settings
id: ada4b0c4-758b-46ac-9033-9004613a150d
related:
    - id: b7216a7d-687e-4c8d-82b1-3080b2ad961f
      type: similar
status: test
description: Detect malicious GPO modifications can be used to implement many other malicious behaviors.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1484.001/T1484.001.md
author: frack113
date: 2022-08-19
tags:
    - attack.privilege-escalation
    - attack.defense-impairment
    - attack.t1484.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_reg:
        - Image|endswith: '\reg.exe'
        - OriginalFileName: 'reg.exe'
    selection_path:
        CommandLine|contains: '\SOFTWARE\Policies\Microsoft\Windows\System'
    selection_key:
        CommandLine|contains:
            - GroupPolicyRefreshTimeDC
            - GroupPolicyRefreshTimeOffsetDC
            - GroupPolicyRefreshTime
            - GroupPolicyRefreshTimeOffset
            - EnableSmartScreen
            - ShellSmartScreenLevel
    condition: all of selection_*
falsepositives:
    - Legitimate use
level: medium