User Discovery And Export Via Get-ADUser Cmdlet — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2022-09-09 / 2022-11-17.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 7ffd0d4f3bf86c0dd59e138aac19f745d47e9ab14836ea71a33b629198f13635

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: User Discovery And Export Via Get-ADUser Cmdlet
id: 1114e048-b69c-4f41-bc20-657245ae6e3f
related:
    - id: c2993223-6da8-4b1a-88ee-668b8bf315e9
      type: similar
status: test
description: Detects usage of the Get-ADUser cmdlet to collect user information and output it to a file
references:
    - http://blog.talosintelligence.com/2022/09/lazarus-three-rats.html
    - https://www.microsoft.com/en-us/security/blog/2022/10/18/defenders-beware-a-case-for-post-ransomware-investigations/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-09
modified: 2022-11-17
tags:
    - attack.discovery
    - attack.t1033
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\powershell.exe'
              - '\pwsh.exe'
        - OriginalFileName:
              - 'PowerShell.EXE'
              - 'pwsh.dll'
    selection_cli:
        CommandLine|contains|all:
            - 'Get-ADUser '
            - ' -Filter \*'
        CommandLine|contains:
            - ' > '
            - ' | Select '
            - 'Out-File'
            - 'Set-Content'
            - 'Add-Content'
    condition: all of selection_*
falsepositives:
    - Legitimate admin scripts may use the same technique, it's better to exclude specific computers or users who execute these commands or scripts often
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate admin scripts may use the same technique, it's better to exclude specific computers or users who execute these commands or scripts often

Source references

• http://blog.talosintelligence.com/2022/09/lazarus-three-rats.html
• https://www.microsoft.com/en-us/security/blog/2022/10/18/defenders-beware-a-case-for-post-ransomware-investigations/