Entra ID ROPC Password Guessing Inferred from AADSTS50126 Errors

Duo Tech@duotech

•updated Jul 14, 2026•1•0•3

Detects potential Resource Owner Password Credential (ROPC) password guessing attempts in Entra ID by monitoring for multiple AADSTS50126 (Invalid Username or Password) errors. Attackers may abuse ROPC to bypass multi-factor authentication requirements or perform brute-force attacks against cloud identities.