The Critical Attack Surface of Passkey Enrollment Flows

Passkeys: Strong by Design, Vulnerable by Implementation

Passkeys have rapidly gained traction as a superior alternative to traditional passwords, offering robust cryptographic protection against phishing attacks. Major platforms, including Microsoft Entra ID, are increasingly adopting them as default, signaling a critical shift in how enterprises secure user access. This move promises to mitigate credential theft, a long-standing challenge in cybersecurity. However, recent developments highlight a critical paradox: while the underlying cryptography of passkeys remains inherently phishing-resistant, the processes surrounding their enrollment and management have become a fertile ground for sophisticated social engineering and technical exploitation.

The Exploitation of Human and Process Elements

Adversaries are adapting their tactics, no longer needing to crack the cryptographic strength of passkeys. Instead, they are targeting the human element and operational vulnerabilities within passkey lifecycle management. This means exploiting user trust, lack of awareness, or procedural flaws during enrollment and recovery. For enterprise security architects, CISOs, and IAM engineers, understanding these evolving attack vectors is paramount to maintaining a secure identity posture.

Social Engineering and Vishing Campaigns

One of the most pervasive new threats involves social engineering, particularly vishing (voice phishing). Attackers impersonate legitimate IT support or trusted entities, coercing users into enrolling attacker-controlled passkeys onto their accounts. A widespread campaign, dubbed 'Pink' by researchers, specifically targets Microsoft 365 passkey enrollment processes. Threat actors utilize sophisticated phishing kits that mimic legitimate Microsoft Entra ID login pages in real-time, prompting users to "enroll a new passkey." Concurrently, they call the target, guiding them through the seemingly legitimate enrollment steps, ultimately registering the attacker's passkey to the victim's account [7].

This tactic cleverly leverages the very strength of passkeys – their binding to specific devices – against the user. By exploiting the user's trust and unfamiliarity with the new enrollment flows, attackers bypass the phishing-resistant nature of the passkey itself.

Improper Authorization and Cross-Organizational Takeovers

Beyond social engineering, technical vulnerabilities in Identity and Access Management (IAM) platforms can also expose passkey enrollment flows to compromise. A recent cluster of vulnerabilities discovered in the ZITADEL identity platform (CVE-2026-105209, CVSS 9.3) illustrates this risk. This critical improper authorization flaw allowed attackers with minimal user-write permissions in one organization to obtain passkey enrollment codes for users in other organizations on the same instance. By registering their own authenticator, attackers could effectively take over accounts across different organizational boundaries [6, 9].

This incident underscores that while passkeys enhance user authentication, the broader CIAM infrastructure responsible for their management, authorization, and lifecycle remains a critical attack surface. Errors in how organizations and platforms implement enrollment, especially in multi-tenant or multi-organizational environments, can undermine the security benefits of passkeys.

Implications for Enterprise Security Teams

The emergence of these sophisticated attack vectors demands a re-evaluation of enterprise passkey adoption strategies:

• Comprehensive User Education: Enterprises must go beyond simply enabling passkeys. Extensive training is required to educate users on legitimate enrollment procedures, common social engineering tactics, and how to identify suspicious requests. Users need to understand that legitimate passkey enrollments will not typically involve unsolicited phone calls or urgent prompts.

• Enhanced CIAM Governance and Monitoring: Strict governance policies around passkey enrollment, recovery, and revocation are essential. IAM teams must implement robust monitoring for unusual enrollment activities, such as multiple passkeys registered to a single user in a short period, or enrollments originating from atypical locations or devices.

• Secure Enrollment Process Design: Developers and architects integrating passkeys into their systems must scrutinize the security of their enrollment flows. This includes rigorous validation of authorization mechanisms, especially in multi-organizational contexts, to prevent the types of flaws seen in ZITADEL.

• Layered Security Controls: While passkeys are strong, they are not a silver bullet. Enterprises should continue to leverage layered security controls, including conditional access policies, device trust, and anomaly detection, to complement passkey security.

• Vendor Due Diligence: When selecting or utilizing CIAM platforms, enterprises must perform thorough due diligence regarding their passkey implementation, scrutinizing their security architecture, authorization models, and incident response capabilities related to passkey lifecycle management.

Conclusion

Passkeys represent a monumental leap forward in addressing traditional credential-based attacks. However, their true security potential is realized only when implemented and managed with an acute awareness of the evolving threat landscape. The recent surge in social engineering attacks targeting enrollment processes and critical vulnerabilities in CIAM platforms underscore that the weakest link often lies not in the cryptography itself, but in the human and process layers surrounding it. Enterprises must proactively address these emerging attack surfaces to ensure their passkey deployments deliver on their promise of superior authentication security.