Passkeys and device biometrics reduce password reuse and phishing exposure, but they often confirm possession of a device or prior enrolment rather than the true claimant. If the original identity proofing was weak, the stronger factor simply protects the wrong identity more efficiently. IAM teams need assurance, not just convenience.
Why This Matters for Security Teams
Passkeys and device biometrics are a real improvement over passwords, but they do not eliminate identity risk. They mainly strengthen the authentication ceremony on a device, while the harder problem remains upstream: whether the user was correctly proofed, enrolled, and bound to the right account in the first place. NIST’s Cybersecurity Framework 2.0 still treats identity assurance as a governance problem, not just a login feature.
That distinction matters because attackers rarely need to defeat a passkey when they can exploit weak recovery flows, stolen devices, session theft, or a bad initial identity binding. The same pattern shows up in non-human identity failures: stronger controls do not help if the wrong principal was trusted from the start, a point reinforced in NHI Management Group’s Ultimate Guide to NHIs and the 52 NHI Breaches Analysis. In practice, many security teams discover the gap only after account takeover, recovery abuse, or privilege escalation has already occurred, rather than through intentional assurance testing.
How It Works in Practice
Passkeys replace shared secrets with cryptographic proof tied to a device or authenticator, and device biometrics unlock that authenticator locally. That reduces phishing and password reuse, but it does not automatically prove that the person holding the device is the rightful account owner. The security outcome depends on the identity lifecycle around the passkey: proofing, enrollment, recovery, step-up verification, and device re-binding.
Practitioners should think in layers:
Identity proofing: verify the claimant before enrollment, especially for high-value accounts and recovery channels.
Authenticator binding: ensure the passkey is associated with the intended identity, not just a reachable device.
Recovery controls: protect reset flows with stronger checks than the day-to-day login path.
Session governance: monitor for token theft, device compromise, and impossible travel after successful authentication.
Assurance-based access: raise verification requirements when risk changes, instead of treating passkey success as final proof.
This is where guidance from NIST CSF 2.0 and identity programs converge with the broader lessons in Ultimate Guide to NHIs: strong authentication is not the same thing as strong identity assurance. If the enrollment workflow is weak, the organization is simply making it harder for an attacker to abuse the wrong identity. These controls tend to break down when consumer-grade recovery flows are reused for privileged workforce access because the assurance bar becomes inconsistent across the lifecycle.
Common Variations and Edge Cases
Tighter identity assurance often increases enrollment friction and help desk overhead, so organisations have to balance user experience against the risk of account takeover. Current guidance suggests that passkeys are best treated as a stronger authenticator, not a complete identity proofing strategy, and there is no universal standard for every recovery scenario yet.
Some environments need additional safeguards:
Shared or managed devices, where one authenticator may be exposed to multiple users or admins.
High-risk roles, where passkey success should be paired with phishing-resistant step-up checks and transaction approval.
Federated identity, where the relying party inherits assurance decisions made by an external IdP.
Bring-your-own-device programs, where device posture varies and biometrics may mask underlying compromise.
This is also why identity teams should not assume passkeys solve the same problems for every principal type. Human accounts, service accounts, and machine identities all need different assurance models, and NHI Management Group’s Top 10 NHI Issues shows how often privilege and lifecycle gaps dominate real incidents. The practical takeaway is simple: use passkeys to reduce credential theft, but keep testing whether the right identity was enrolled, whether recovery is harder to abuse than login, and whether the access decision still matches risk at runtime.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 address the attack and risk surface, while NIST CSF 2.0 and NIST SP 800-63 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | PR.AA-01 | Identity proofing and authenticator binding are core to assurance. |
| NIST SP 800-63 | IAL/AAL/FAL | Passkeys solve authentication, but assurance depends on proofing levels. |
| OWASP Non-Human Identity Top 10 | NHI-01 | The same binding and lifecycle gaps seen in NHIs apply to human identity assurance. |
Treat passkeys as one control in an identity assurance lifecycle, not as proof that access is always legitimate.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on June 23, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
