Defending SaaS-based applications against ShinyHunters OAuth abuse

Microsoft Threat Intelligence observed activity consistent with the ShinyHunters actor abusing OAuth and SaaS ecosystems: voice‑phishing (vishing), supply‑chain compromise, and exploitation of misconfigured guest access to obtain OAuth consents and persist in SaaS environments. The report warns of OAuth token abuse leading to data access/exfiltration and provides defensive guidance (tighten guest access and app consent policies, monitor and revoke suspicious tokens, enforce least privilege and modern authentication). Related Microsoft posts in the same feed reinforce identity hygiene (Entra ID