Prioritise hardware based WebAuthn when the protected systems are high value, the threat model includes phishing, or account takeover would be costly. OTP apps and push approvals improve convenience and can be stronger than passwords, but they still depend on channels that can be intercepted or socially engineered. Hardware keys reduce that risk by binding authentication to a unique key pair.
When hardware based passwordless methods earn the priority
Hardware based WebAuthn becomes the better default when the authentication decision must hold up under active attack, not just routine use. It is most justified where phishing, AiTM interception, push fatigue, help desk social engineering, or credential replay would have outsized impact. In those settings, the question is less convenience and more whether the method can resist real takeover attempts.
OTP and push approvals can still improve security compared with passwords alone, but they remain vulnerable to channel abuse. A code can be relayed, a push can be accepted by mistake, and a recovery path can become the weakest link. Hardware based methods change the trust model by requiring possession of a key that signs the challenge for the specific origin.
For teams deciding where to place the stronger method, the practical threshold is usually the combination of asset value and compromise cost. If a successful login would expose administrative consoles, financial workflows, production data, or sensitive internal systems, then the incremental resistance of a hardware key usually outweighs the additional user friction.
Why OTP and push are weaker in high consequence environments
OTP and push are not the same control, but they share a common limitation: the user still approves a login event through a channel that can be manipulated. OTP depends on a transmittable secret, while push approvals can be coerced through repetition, social pressure, or poor approval habits. That makes both methods more fragile against phishing and session theft than phishing resistant authentication.
Hardware based WebAuthn reduces that fragility because the private key never leaves the authenticator and the response is bound to the site or application origin. That binding is what changes the risk profile. It means a captured code or an approval click is no longer enough to satisfy the login ceremony in a different context.
Teams should also distinguish between protecting the first login and protecting the full account lifecycle. If password reset, help desk recovery, or step up authentication still rely on weaker channels, attackers may bypass the stronger primary factor by targeting the fallback process instead.
How to choose the right method by threat model and user population
Use hardware keys first for administrators, privileged operators, finance users, executives, and anyone with access to systems where account takeover would create a large blast radius. For lower risk populations, app based OTP or push may be an acceptable transition step, especially where device distribution, budget, or user readiness is still being built out.
Selection should also reflect the attack surface around the account. If users are routinely targeted by phishing, travel often, work across unmanaged devices, or access many external portals, hardware based authentication deserves earlier adoption. If the environment is low consequence and the main objective is to remove passwords quickly, OTP or push may be a reasonable interim control, but not the end state for sensitive access.
Where the organisation has both broad workforce access and a smaller set of high privilege accounts, the best pattern is often mixed. Reserve hardware based methods for the accounts whose compromise would be hardest to detect or recover from, and keep the simpler method only where the residual risk is truly modest.
Risk and Threat Considerations
Authentication weakness becomes materially more dangerous when the attacker only needs one successful approval or one relayed code to obtain durable access. OTP and push methods are attractive because they are widely deployed and easy to social engineer, especially when the attacker can combine phishing, MFA fatigue, or help desk impersonation with stolen credentials.
Failure mechanism: The adversary captures or relays a one time code, coerces an approval, or exploits a recovery path that is weaker than the primary login factor, then uses the resulting session to move into high value systems.
Impact: The result can be full account takeover, privileged access abuse, session theft, and downstream compromise of systems where the authentication event is treated as sufficient proof of trust.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-63 and CIS Controls v8 set the technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-63 | Phishing-Resistant Authentication | Hardware WebAuthn directly addresses phishing-resistant auth and authenticator assurance. |
| Recommendation — Use phishing-resistant authenticators for high-value accounts and reduce reliance on OTP or push approval flows. | ||
| CIS Controls v8 | CIS-6 — Access Control Management | Authentication strength influences account access protection and privileged access exposure. |
| Recommendation — Prioritise stronger authentication for accounts with elevated access and sensitive business impact. | ||
| ISO/IEC 27001:2022 | A.5.15 — Access control | Choosing stronger authentication is part of access control design for sensitive systems. |
| Recommendation — Apply stronger access controls where compromise would materially affect business or security outcomes. | ||
Practitioner Guidance
What to prioritise: Start with the accounts where compromise would cause the hardest recovery, not the accounts with the most users. That usually means privileged users, financial approvers, support staff with reset authority, and any external login path exposed to phishing.
What to verify: Confirm that the fallback and recovery flow is at least as strong as the primary login method. If the user can be reset through email, SMS, or a lightly reviewed help desk process, the stronger authenticator is only partially effective.
Decision rule: If the account protects production administration, sensitive customer data, or high value transactions, make hardware based authentication the standard unless a documented exception exists. If the account is low consequence and recovery risk is controlled, OTP or push may be acceptable temporarily.
Practitioner takeaway: Choose hardware based passwordless methods when the organisation needs phishing resistance and durable trust, not just easier sign in. The more costly the account takeover, the less acceptable it is to rely on an approval channel that can still be tricked.
Related resources from NHI Mgmt Group
- Should API security teams prioritise business logic abuse over signature-based scanning?
- When should teams prioritise one third party over another in a risk-based due diligence program?
- When should security teams prioritise more granular access control over simpler role-based access?
- When should organisations prioritise LLM-based anomaly detection over traditional parameter-tuned methods?
