Teams should inventory each application or authentication scenario and map who needs access, which authentication approach will be used, and how access is currently managed through IAM, IdP, PAM, SSO, or VPN. They should also document workforce patterns and device types, including owned endpoints, BYOD, desktops, laptops, smartphones, tablets, POS terminals, and inventory scanners.
What to inventory before a passwordless migration
Start by inventorying every place authentication happens, not just every login screen. The useful unit is the application or access scenario, then the people, devices, and control paths behind it. That means mapping who needs access, how the session is initiated, and which IAM, IdP, PAM, SSO, or VPN dependency currently brokers the trust decision.
A complete inventory should also capture workforce patterns and endpoint posture because phishing-resistant MFA rarely lands in a uniform environment. An office desktop with managed policies, a BYOD smartphone, and a POS terminal or inventory scanner do not support the same authenticator choices, recovery paths, or exception handling. The migration fails when teams treat all users as if they share one operating model.
For practitioners, the inventory is the design input that prevents you from selecting an authentication method that is secure in theory but unusable or ungovernable in practice.
Why the inventory has to be scenario-based
Phishing-resistant MFA is not a single control you can bolt onto an organisation as a blanket replacement. It changes by scenario because the risk is tied to the combination of application sensitivity, user population, device trust, and current access orchestration. A privileged admin path, a frontline workforce portal, and a contractor VPN entry point may all need different enrollment, enforcement, or fallback models.
This is especially important where the current environment already uses multiple trust brokers. If access is split across IdP sign-in, VPN entry, and PAM-controlled elevation, the team must know where the authenticator is actually being validated and where the real privilege boundary sits. That boundary determines what must be modernised first and where legacy authentication dependencies may remain exposed during the transition.
NIST SP 800-63 Digital Identity Guidelines is the clearest external reference for aligning authenticator choice, assurance, and phishing resistance to the access scenario rather than to a generic user population.
What good migration planning looks like in practice
Use the inventory to separate steady-state users from exception cases. If a device can support modern authenticators, the path should favour phishing-resistant MFA with minimal fallback. If the endpoint is shared, unmanaged, or operationally constrained, the team should decide in advance whether access is allowed, isolated, brokered, or deferred until the device and workflow are brought into scope.
Good planning also means documenting what must remain during coexistence. Many organisations will need a period where some users are on phishing-resistant MFA while others still depend on legacy flows. During that window, the highest-value work is understanding where the weaker path is still accepted, how recovery is performed, and which privileged workflows need tighter controls while the migration is incomplete.
The strongest inventory is one that can answer three questions without guesswork: what is being protected, what device or access context is used, and what happens when the preferred authenticator is unavailable.
Risk and Threat Considerations
The main risk is not just failing to replace passwords, it is leaving hidden authentication paths in place after the new control is deployed. Mixed environments often preserve legacy sign-in, recovery, or admin exceptions that attackers can target, especially where a weaker path still reaches high-value accounts or tools.
Failure mechanism: An incomplete inventory misses one-off applications, shared devices, break-glass paths, or privileged access workflows, so phishing-resistant MFA is rolled out only on the obvious systems while the real exposure remains in the exceptions.
Impact: Attackers can concentrate on the residual password-based or weakly protected path, turning the migration into a partial control rather than a material reduction in account takeover risk.
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, CIS Controls v8, NIST CSF 2.0 and NIST Zero Trust (SP 800-207) set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-63 | IAL/AAL/FAL — Identity Assurance Level / Authenticator Assurance Level / Federation Assurance Level | Phishing-resistant MFA selection depends on authenticator assurance and federation context. |
| Recommendation — Map each scenario to the required AAL and choose authenticators that resist phishing. | ||
| CIS Controls v8 | 6 — Access Control Management | The inventory defines who should access which apps and how access is brokered today. |
| 5 — Account Management | Migration requires knowing where accounts, recovery, and privileged access still rely on passwords. | |
| Recommendation — Inventory access paths and remove weaker authentication from high-risk systems. Identify and manage accounts that still depend on password-based recovery or login. | ||
| NIST CSF 2.0 | PR.AC — Access Control | The question is about controlling access with stronger authentication and managing access paths. |
| ID.AM — Asset Management | Teams must inventory applications, devices, and access scenarios before changing authentication. | |
| Recommendation — Use PR.AC to enforce stronger authentication at each access boundary. Build an inventory of applications, users, and devices before changing authentication methods. | ||
| NIST Zero Trust (SP 800-207) | 4 — Access Control | Phishing-resistant MFA fits zero-trust access decisions that validate each request by context. |
| Recommendation — Treat each application and session as an explicit access decision with verified context. | ||
Practitioner Guidance
What to prioritise: Inventory the authentication paths that can reach privileged functions, external-facing applications, and recovery workflows first. Those are the places where a missed exception creates the largest residual exposure.
What to verify: Confirm not only that a user can enroll in phishing-resistant MFA, but also that the device, policy, and recovery model can support sustained use without falling back to weaker authentication in day-to-day operations.
Common mistake: Treating “passwordless rollout” as a directory project instead of an access-path project. The control only works if you know every place a person can still enter the environment, elevate privilege, or recover access.
Practitioner takeaway: The inventory should expose where trust is actually enforced, because the migration succeeds only when every meaningful access path, including exceptions, is explicitly designed for the new authenticator model.
Related resources from NHI Mgmt Group
- How should security teams implement phishing-resistant MFA for privileged SaaS access?
- How should security teams implement phishing-resistant MFA for CMMC-scoped systems?
- How should security teams implement phishing-resistant MFA across multiple IAM systems?
- How can IAM teams tell whether phishing-resistant MFA is actually improving security?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 19, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
