What breaks when machine identities are not included in passwordless plans?

Why This Matters for Security Teams

Passwordless initiatives often succeed for humans first and fail quietly for everything else. If machine identities are left out, service accounts, API keys, certificates, CI/CD runners, and device trust still depend on legacy secrets and ad hoc exemptions. That creates a split control plane: humans authenticate with stronger methods while workloads remain exposed to lateral movement, token theft, and brittle trust chains. NHI Mgmt Group notes that 90% of IT leaders say properly managing NHIs is essential for a successful zero-trust implementation, which is why passwordless planning cannot stop at the user login layer.

The risk is not theoretical. Breach cases such as the Schneider Electric credentials breach and JetBrains GitHub plugin token exposure show how machine secrets can turn a narrow compromise into broad access. The NIST Cybersecurity Framework 2.0 treats identity as a core control surface, but many teams still scope passwordless to workforce SSO and MFA only. In practice, many security teams discover the machine gap only after an exposed token or certificate has already been used to pivot across systems.

How It Works in Practice

A complete passwordless program has to define how non-human subjects authenticate, present proof, and are revoked. For machines, that usually means certificate-based or workload-identity-based trust rather than a password replacement. The key question is not whether a device or service can avoid typing a secret, but whether it can prove what it is at runtime, under policy, and with short-lived trust. Current guidance suggests aligning this with zero standing privilege and reducing long-lived secrets wherever possible.

In practice, teams should inventory every machine path that touches production or sensitive data: service-to-service calls, build agents, mobile endpoints, IoT devices, signed software updates, and automation bots. Then map each one to an identity primitive such as certificates, federated workload identity, or attested device credentials. NHI Mgmt Group research shows only 5.7% of organisations have full visibility into their service accounts, which means many passwordless projects start with incomplete scope and miss the very identities that keep systems running.

• Use distinct controls for humans and non-humans instead of assuming one SSO pattern fits both.
• Issue short-lived credentials or certificates where possible, and revoke them automatically when workloads end.
• Bind secrets and tokens to workload identity, not to static infrastructure addresses or shared accounts.
• Continuously review signed communications, CI/CD trust, and API access paths for fallback credentials.

The NIST Cybersecurity Framework 2.0 is useful for structuring this inventory and governance work, while the NHIMG guide to non-human identities is a practical reference for lifecycle, rotation, and visibility gaps. These controls tend to break down in hybrid estates where legacy protocols, embedded devices, and shared service accounts cannot yet support certificate-based trust or automated revocation.

Common Variations and Edge Cases

Tighter passwordless controls often increase integration overhead, so organisations have to balance rollout speed against coverage gaps. That tradeoff is especially visible in environments with OT, embedded systems, or third-party managed services, where replacing passwords may require firmware changes, new trust brokers, or contract updates.

There is no universal standard for this yet, but current guidance suggests treating exceptions as temporary and documented. A device that cannot do modern authentication should not silently inherit the same trust as a strongly bound workload. Instead, place it behind segmented access, constrained network policy, or brokered access with aggressive monitoring. The same principle applies to signed code and automation pipelines: if a machine identity cannot be represented in the passwordless design, it becomes an exception that attackers can target.

This is where passwordless programs often drift into false completeness. The strongest human login flow does little if API keys remain in source control, certificates never rotate, or build systems keep standing access to production. The NHIMG research on the JetBrains GitHub plugin token exposure is a reminder that tooling trust chains are part of identity design, not a side issue. In mixed environments, the safe answer is to phase coverage by identity type, not by convenience.

Related resources from NHI Mgmt Group

• How do passwordless controls affect machine and service access?
• What breaks when passwordless is rolled out to only part of an application estate?
• What breaks when passwordless authentication is deployed without lifecycle controls?
• Why do ephemeral credentials still leave risk in machine access models?