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Detection rules › Sigma

Active Directory Computers Enumeration With Get-AdComputer

Status
test
Severity
low
Log source
product windows, category ps_script
Author
frack113
Source
github.com/SigmaHQ/sigma

Detects usage of the "Get-AdComputer" to enumerate Computers or properties within Active Directory.

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1018 Remote System Discovery, T1087.002 Account Discovery: Domain Account

Event coverage

ProviderEventTitle
PowerShellEvent ID 4104Creating Scriptblock text (MessageNumber of MessageTotal).

Rule body yaml

title: Active Directory Computers Enumeration With Get-AdComputer
id: 36bed6b2-e9a0-4fff-beeb-413a92b86138
status: test
description: Detects usage of the "Get-AdComputer" to enumerate Computers or properties within Active Directory.
references:
    - https://learn.microsoft.com/en-us/powershell/module/activedirectory/get-adcomputer
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1018/T1018.md
    - https://github.com/redcanaryco/atomic-red-team/blob/02cb591f75064ffe1e0df9ac3ed5972a2e491c97/atomics/T1087.002/T1087.002.md
author: frack113
date: 2022-03-17
modified: 2023-07-08
tags:
    - attack.discovery
    - attack.t1018
    - attack.t1087.002
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_cmdlet:
        ScriptBlockText|contains: 'Get-AdComputer '
    selection_option:
        ScriptBlockText|contains:
            - '-Filter '
            - '-LDAPFilter '
            - '-Properties '
    condition: all of selection_*
falsepositives:
    - Unknown
level: low

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_cmdlet

selection_cmdlet:
    ScriptBlockText|contains: 'Get-AdComputer '

Stage 2: selection_option

selection_option:
    ScriptBlockText|contains:
        - '-Filter '
        - '-LDAPFilter '
        - '-Properties '

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
ScriptBlockTextmatch
  • -Filter
  • -LDAPFilter
  • -Properties
  • Get-AdComputer corpus 2 (sigma 2)