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Why do passwordless programmes need to include systems and machines?

Because modern identity estates are not limited to people. Systems and machines also access corporate resources, and if they are left out of the authentication and governance redesign, organisations can improve human login security while leaving persistent machine access under-governed. Passwordless only becomes complete when all identity classes are reviewed against their real access paths.

Why passwordless has to cover systems and machines, not just people

Passwordless programmes are really identity programmes. If the rollout only modernises human sign-in, organisations can still leave service accounts, workloads, scripts, APIs and devices relying on passwords, shared keys or unmanaged secrets. That creates a split estate where one part is hardened and another remains easy to overprivilege, reuse or forget.

What changes when machines are included in the redesign

Machines authenticate differently from people, but they still need a trustworthy way to prove who or what they are. In practice, that means reviewing non-human identities alongside workforce sign-in, then replacing legacy secrets with controls that fit machine use cases such as certificates, federated identity, managed tokens or workload-bound credentials. The goal is not “human passwordless for machines”, but equivalent trust without standing passwords.

That review matters because machine access often sits on the critical path of business processes. A forgotten integration can keep using a long-lived password for months, even after employees have moved to passkeys. The result is not a failed passwordless programme, but an incomplete one.

Why incomplete coverage creates governance blind spots

When systems and machines are excluded, the organisation loses sight of where authentication still exists, who owns it, and how it is rotated or revoked. That makes access reviews harder, incident response slower, and decommissioning less reliable. In other words, passwordless can reduce user friction while leaving the hardest governance problem untouched.

For practitioner context, the same design principle appears in Passwordless and Passkeys Guide, which ties phishing-resistant sign-in to recovery and rollout decisions, and in Workforce Identity Security Guide, which shows how authentication changes must be matched to lifecycle and recovery controls. The same governance logic also applies to machine access, even if the implementation pattern is different.

Risk and Threat Considerations

Leaving systems and machines out of passwordless redesign creates a residual attack surface that is often more durable than human login risk. Long-lived machine secrets are attractive because they are hard to notice, easy to reuse across environments, and often tied to automation that breaks if the secret is changed casually.

Failure mechanism: A passwordless rollout that ignores machine identities leaves legacy credentials, API keys, certificates or shared secrets in place, which preserves standing access and weakens revocation, rotation and blast-radius control.

Impact: An attacker who steals or abuses that residual access can move through production systems, keep persistence through automation, and bypass the security gains achieved on the human side of the programme.

The underlying threat pattern is well captured by the Twilio 0ktapus breach 2022, where credential theft enabled broader compromise, and by the broader authentication guidance in NIST SP 800-63 Digital Identity Guidelines, which reinforces that strong authentication has to be paired with the right assurance and recovery model. For machine access, the same principle is that strength without inventory and lifecycle control still leaves exploitable gaps.

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 addresses the attack and risk surface, while NIST SP 800-63 and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.

Framework Control / Reference Relevance
NIST SP 800-63 Digital Identity Guidelines Strongly governs phishing-resistant authentication and assurance for passwordless sign-in.
Recommendation — Apply the assurance and authenticator guidance to replace passwords with phishing-resistant methods.
NIST SP 800-53 Rev 5 IA-5 — Authenticator Management Machine and human passwordless redesign must manage the lifecycle of remaining authenticators and secrets.
IA-9 — Service Identification and Authentication Machine and service access is central to the question because non-human identities also authenticate.
Recommendation — Inventory, rotate, and revoke authenticators and secrets that still support access. Use service authentication controls for workloads, APIs, and other non-human access paths.
OWASP Non-Human Identity Top 10 NHI-02 — Secret Leakage Residual machine access often persists through leaked or unmanaged secrets.
NHI-07 — Long-Lived Secrets Passwordless programmes fail when machine credentials remain static and durable.
Recommendation — Eliminate exposed secrets and replace them with governed non-human authentication. Replace long-lived machine secrets with short-lived, revocable credentials.

Practitioner Guidance

What to prioritise: Start by inventorying every machine-to-machine and system-to-system access path before calling the programme complete. If a workload, job, integration or device still depends on a password or static secret, treat it as part of the passwordless redesign, not an exception to it.

What to verify: Confirm who owns each non-human credential, how it is rotated, what it can reach, and whether it can be revoked without breaking production. If the access path cannot be described in those terms, the estate is not yet governable.

Common mistake: Teams often measure success only by the number of people who have moved to passkeys or MFA-free sign-in. That misses the bigger question, which is whether every identity class has been re-authenticated, re-approved and re-governed on its actual access path.

Practitioner takeaway: Passwordless is complete only when the organisation removes standing secrets wherever identity is used, because the remaining machine paths usually determine whether the control change is durable or merely cosmetic.