title: Active Directory Replication from Non Machine Account
id: 17d619c1-e020-4347-957e-1d1207455c93
description: Detects potential abuse of Active Directory Replication Service (ADRS) from a non machine account to request credentials.
status: experimental
date: 2019/07/26
modified: 2020/08/23
author: Roberto Rodriguez @Cyb3rWard0g
references:
    - https://threathunterplaybook.com/notebooks/windows/06_credential_access/WIN-180815210510.html
tags:
    - attack.credential_access
    - attack.t1003          # an old one
    - attack.t1003.006
logsource:
    product: windows
    service: security
detection:
    selection:
        EventID: 4662
        AccessMask: '0x100'
        Properties|contains:
            - '1131f6aa-9c07-11d1-f79f-00c04fc2dcd2'
            - '1131f6ad-9c07-11d1-f79f-00c04fc2dcd2'
            - '89e95b76-444d-4c62-991a-0facbeda640c'
    filter:
        - SubjectUserName|endswith: '$'
        - SubjectUserName|startswith: 'MSOL_' #https://docs.microsoft.com/en-us/azure/active-directory/hybrid/reference-connect-accounts-permissions#ad-ds-connector-account
    condition: selection and not filter
fields:
    - ComputerName
    - SubjectDomainName
    - SubjectUserName
falsepositives:
    - Unknown
level: critical