Suspicious Get-ADReplAccount

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

The DSInternals PowerShell Module exposes several internal features of Active Directory and Azure Active Directory. These include FIDO2 and NGC key auditing, offline ntds.dit file manipulation, password auditing, DC recovery from IFM backups and password hash calculation.

Known false positives

Legitimate PowerShell scripts

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1003.006` OS Credential Dumping: DCSync

Telemetry coverage

Provider	Record / event type
PowerShell	Event ID 4104: Creating Scriptblock text (MessageNumber of MessageTotal).

Rule body

title: Suspicious Get-ADReplAccount
id: 060c3ef1-fd0a-4091-bf46-e7d625f60b73
status: test
description: |
    The DSInternals PowerShell Module exposes several internal features of Active Directory and Azure Active Directory.
    These include FIDO2 and NGC key auditing, offline ntds.dit file manipulation, password auditing, DC recovery from IFM backups and password hash calculation.
references:
    - https://www.powershellgallery.com/packages/DSInternals
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1003.006/T1003.006.md#atomic-test-2---run-dsinternals-get-adreplaccount
author: frack113
date: 2022-02-06
tags:
    - attack.credential-access
    - attack.t1003.006
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - Get-ADReplAccount
            - '-All '
            - '-Server '
    condition: selection
falsepositives:
    - Legitimate PowerShell scripts
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    ScriptBlockText|contains|all:
        - Get-ADReplAccount
        - '-All '
        - '-Server '

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`ScriptBlockText`	match	`-All` `-Server` `Get-ADReplAccount` corpus 2 (sigma 2)	`field:"ScriptBlockText" kind:match`