O-UNC-066 Exploits Microsoft Entra Passkey Enrollment in Vishing Scheme
In April 2026, a threat actor identified as O-UNC-066 initiated a sophisticated vishing campaign targeting Microsoft 365 users across multiple sectors, including food and beverage, technology, healthcare, automotive, construction, and aviation. The attackers impersonated internal security personnel, contacting employees via phone and instructing them to enroll a new Microsoft Entra passkey for enhanced security. Victims were directed to phishing websites that closely mimicked Microsoft's legitimate passkey enrollment process. Unbeknownst to the users, this process allowed the attackers to register their own passkeys, thereby gaining unauthorized access to the victims' Microsoft 365 accounts. Subsequent to gaining access, the attackers engaged in data exfiltration activities, targeting sensitive information stored in SharePoint and OneDrive. ([bleepingcomputer.com](https://www.bleepingcomputer.com/news/security/entra-passkey-enrollment-vishing-targets-microsoft-365-users/?utm_source=openai)) This incident underscores a concerning trend in cyber threats, where attackers exploit legitimate security features to deceive users. The abuse of Microsoft's passkey enrollment process highlights the need for organizations to implement robust user education programs and to remain vigilant against evolving social engineering tactics. ([bleepingcomputer.com](https://www.bleepingcomputer.com/news/security/entra-passkey-enrollment-vishing-targets-microsoft-365-users/?utm_source=openai))
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