Certificate-Based Authentication Enabled — Sigma Rule

Rule metadata and linked tags

Author: Harjot Shah Singh, '@cyb3rjy0t'. Source status: test; severity: medium. Source dates: 2024-03-26 / not supplied.

{
  "product": "azure",
  "service": "auditlogs"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 9f4668b96489278aad27fff1d9aabdb667ffaeccdd403befc75ce91d6343f428

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: Certificate-Based Authentication Enabled
id: c2496b41-16a9-4016-a776-b23f8910dc58
status: test
description: Detects when certificate based authentication has been enabled in an Azure Active Directory tenant.
references:
    - https://posts.specterops.io/passwordless-persistence-and-privilege-escalation-in-azure-98a01310be3f
    - https://goodworkaround.com/2022/02/15/digging-into-azure-ad-certificate-based-authentication/
author: Harjot Shah Singh, '@cyb3rjy0t'
date: 2024-03-26
tags:
    - attack.credential-access
    - attack.persistence
    - attack.privilege-escalation
    - attack.defense-impairment
    - attack.t1556
logsource:
    product: azure
    service: auditlogs
detection:
    selection:
        OperationName: 'Authentication Methods Policy Update'
        TargetResources.modifiedProperties|contains: 'AuthenticationMethodsPolicy'
    condition: selection
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://posts.specterops.io/passwordless-persistence-and-privilege-escalation-in-azure-98a01310be3f
• https://goodworkaround.com/2022/02/15/digging-into-azure-ad-certificate-based-authentication/