Credential added to rarely used Azure AD application

Classification:

attack

Tactic:

TA0003-persistence

Technique:

T1098-account-manipulation

VIEW RULE IN DATADOG VIEW SIGNALS

Set up the azure integration.

Goal

Detects when a user adds a secret or certificate to an Azure Active Directory Application that is not regularly updated.

Strategy

Monitor Azure AD Audit logs for the following @evt.name:

• Update application – Certificates and secrets management
• Add service principal credentials

Monitor Microsoft 365 Audit logs for the following @evt.name:

• Update application – Certificates and secrets management
• Add service principal credentials.

An attacker can add a secret or certificate to an application in order to connect to Azure AD as the application and perform API operation leveraging the application permissions that are assigned to it. An attacker may target an application that is seldom changed to avoid detection. Using the New Value detection method, a signal is raised when an application not seen in the previous 7 days has credentials added.

Triage and response

1. Determine if {{@usr.id}} should have made a {{@evt.name}} API call.
2. If the API call was not made by the user:
   • Remove the suspicious key.
   • Invalidate all existing refresh tokens. This ensures the attacker is unable to connect to your tenant.
   • Begin your organization’s Incident Response (IR) process.
3. If the API call was made by the user:
   • Ensure the change was authorized.

Changelog

2 November 2022 - Updated severity.