Should organisations prioritise Zero Trust for machine identities before broader IAM changes?

Why This Matters for Security Teams

zero trust is often treated as a broad IAM programme, but machine identities are usually where the highest-risk access paths hide. Service accounts, API keys, workload tokens, and certificates can move laterally, call privileged services, and persist far longer than human sessions. NIST SP 800-207 Zero Trust Architecture makes clear that trust must be continuously evaluated, not assumed from network location or identity type.

This matters because machine identities are not just numerous, they are operationally embedded in CI/CD, orchestration, third-party integrations, and application-to-application calls. NHIMG’s Ultimate Guide to NHIs — Standards notes that 90% of IT leaders say properly managing NHIs is essential for a successful zero-trust implementation, which reflects the real sequencing problem: if machine access is still standing privilege, broader IAM work leaves the most exposed paths intact. In practice, many security teams discover this only after a service account has already been used to pivot between systems, rather than through intentional Zero Trust design.

How It Works in Practice

Prioritising Zero Trust for machine identities means constraining what workloads can do before expanding the same discipline to every other identity class. The practical shift is from static trust to runtime verification. Instead of granting a long-lived credential and hoping the surrounding IAM model compensates, organisations should issue short-lived, purpose-bound credentials, evaluate policy at request time, and bind identity to workload proof rather than a reusable secret.

A strong starting point is workload identity. The Guide to SPIFFE and SPIRE is useful here because it reflects the operational idea that a machine identity should prove what it is, not just present a password-like artefact. In many environments, this is paired with OIDC-based federation, mTLS, or service mesh controls so a service can authenticate, receive a narrowly scoped token, and lose that access automatically when the task ends.

• Use Zero Standing Privilege for service accounts and automation first.
• Replace static secrets with just-in-time, short-lived credentials wherever possible.
• Evaluate access with policy-as-code at request time, not only at provisioning time.
• Separate human IAM cleanup from workload identity containment so the riskiest lateral paths are reduced immediately.

Current guidance suggests that the best sequencing is to lock down high-value machine-to-machine pathways first, then extend the same controls across the broader IAM estate. These controls tend to break down when legacy applications require shared static secrets across multiple environments because the credential cannot be safely scoped, rotated, or revoked per task.

Common Variations and Edge Cases

Tighter control over machine identities often increases operational overhead, so organisations must balance faster containment against integration effort. That tradeoff is real, especially where old applications, vendor-managed agents, or embedded devices cannot easily support ephemeral credentials or workload attestation.

There is no universal standard for sequencing every IAM change, but current guidance suggests three common edge cases. First, if machine identities are already driving production access, Zero Trust for workloads should move ahead of broader human IAM modernisation. Second, if identity sprawl is dominated by SaaS users rather than service accounts, the order may be reversed. Third, in hybrid and multi-cloud estates, policy drift is often the real failure mode, which is why NHIMG’s 2024 Non-Human Identity Security Report is relevant: 35.6% of organisations cite consistent access across hybrid and multi-cloud environments as their top NHI security challenge.

Where teams often get stuck is assuming Zero Trust is a perimeter replacement rather than a credential and authorization redesign. That distinction matters because machine identities can be chained, reused, and over-scoped in ways human sessions usually are not. Broader IAM changes still matter, but they rarely remove the most immediate blast radius unless the machine layer is addressed first.

Related resources from NHI Mgmt Group

• When should organisations prioritise Zero Standing Privilege for non-human identities?
• Why do non-human identities complicate zero trust architecture?
• Why do non-human identities increase zero trust risk?
• Should organisations prioritise machine identities before human access reviews?