Azure AD Audit Logs: Certificate-based authentication enabled via AuthenticationMethodsPolicy update

Flags Azure AD audit log events where the Authentication Methods policy is updated to enable certificate-based authentication.

FreeReviewedSigma · Medium · v5
Product
azure
Service
auditlogs
Author
Harjot Shah Singh, '@cyb3rjy0t' (SigmaHQ), DRL 1.1
Published
2024-03-26
Updated
2026-07-31
title: "Azure AD Audit Logs: Certificate-based authentication enabled via AuthenticationMethodsPolicy update"
id: d4148b9c-a43b-45f0-bc74-52f95c5b3ed7
status: test
description: This rule identifies changes in Azure Active Directory where the tenant’s authentication methods policy is updated and includes the AuthenticationMethodsPolicy property. Enabling certificate-based authentication can support passwordless access and persistence, including granting alternate authentication paths that may be difficult to spot in day-to-day activity. It relies on Azure audit log events for the operation name Authentication Methods Policy Update and matches on modifiedProperties containing AuthenticationMethodsPolicy.
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/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/azure/audit_logs/azure_ad_certificate_based_authencation_enabled.yml
author: Harjot Shah Singh, '@cyb3rjy0t', Huntrule Team
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
license: DRL-1.1
related:
  - id: c2496b41-16a9-4016-a776-b23f8910dc58
    type: derived