Novel OAuth Client ID Spoofing Targets Cloud
🔒 Cyber-attackers are increasingly using OAuth client ID spoofing to access cloud environments by abusing Microsoft Entra ID (formerly Azure AD). Proofpoint researchers found threat actors issuing ROPC token requests to the OAuth 2.0 endpoint, producing AADSTS error codes that reveal valid usernames and authentication controls. The technique produces blank or spoofed application IDs in Entra sign‑in logs, making detection difficult and enabling large-scale campaigns targeting millions of accounts.
