title: ADCS Certificate Template Configuration Vulnerability with Risky EKU
id: bfbd3291-de87-4b7c-88a2-d6a5deb28668
status: experimental
description: Detects certificate creation with template allowing risk permission subject and risky EKU
references:
    - https://www.specterops.io/assets/resources/Certified_Pre-Owned.pdf
author: Orlinum , BlueDefenZer
date: 2021/11/17
tags:
    - attack.privilege_escalation
    - attack.credential_access
logsource:
    product: windows
    service: security
    definition: Certificate services loaded a template would trigger event ID 4898 and certificate Services template was updated would trigger event ID 4899. A risk permission seems to be comming if template contain specific flag with risky EKU.
detection:
    selection10:
        EventID: 4898
        TemplateContent|contains:
          - '1.3.6.1.5.5.7.3.2'
          - '1.3.6.1.5.2.3.4'
          - '1.3.6.1.4.1.311.20.2.2'
          - '2.5.29.37.0'
    selection11:
        TemplateContent|contains: 'CT_FLAG_ENROLLEE_SUPPLIES_SUBJECT'

    selection20:
        EventID: 4899
        NewTemplateContent|contains:
          - '1.3.6.1.5.5.7.3.2'
          - '1.3.6.1.5.2.3.4'
          - '1.3.6.1.4.1.311.20.2.2'
          - '2.5.29.37.0'
    selection21:
        NewTemplateContent|contains: 'CT_FLAG_ENROLLEE_SUPPLIES_SUBJECT'

    condition: (selection10 and selection11) or (selection20 and selection21)
falsepositives:
    - Administrator activity
    - Proxy SSL certificate with subject modification
    - Smart card enrollement
level: high
