[New Rule] OIDC Discovery URL Changed in Entra ID

[terrancedejesus]

Pull Request

Issue link(s):

Summary - What I changed

Adds detection logic via ES|QL for OIDC discovery URL changes. This may indicate post-compromise behavior related to bring-your-own IdP where a compromised account setup an external IdP in Entra to manipulate OIDC auth workflows and bypass MFA. Please see the related issue for more details.

How To Test

Checklist

• Added a label for the type of pr: bug, enhancement, schema, maintenance, Rule: New, Rule: Deprecation, Rule: Tuning, Hunt: New, or Hunt: Tuning so guidelines can be generated
• Added the meta:rapid-merge label if planning to merge within 24 hours
• Secret and sensitive material has been managed correctly
• Automated testing was updated or added to match the most common scenarios
• Documentation and comments were added for features that require explanation

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• Have you signed the contributor license agreement?
• Have you followed the contributor guidelines?

[github-actions]

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