ROPC

2026-05-135 minVaronismedium

A nuance in the Entra ID Resource Owner Password Credentials (ROPC) protocol allows attackers with compromised credentials to authenticate against a permissive external tenant, generating a 'Sign-in: Success' log in the victim's home tenant. While this cross-tenant authentication does not grant access to the victim's data, it effectively poisons UEBA models and floods the SOC with false positive alerts, creating significant operational disruption and compromising log integrity.

2026-05-135 minTrend Microhigh

Threat actors exploited an exposed Spring Boot Actuator endpoint and plaintext credentials found in a spreadsheet to authenticate via the legacy ROPC flow. This allowed them to bypass MFA, obtain a Microsoft Graph access token, and exfiltrate sensitive data from SharePoint Online without deploying malware.