Spoofed OAuth Client ID Observed Across Multiple Tenants and Authenticating Against 2+ Distinct Tenants

Detects sign-in attempts where the OAuth Client ID (AppId) does not have a corresponding display name (AppDisplayName) in the logs, and the same Client ID is observed across multiple different Azure tenants. This pattern often indicates an adversary using a malicious or spoofed OAuth application to perform multi-tenant abuse, consent phishing, or unauthorized access across different organizational boundaries.