Should organisations prioritise Zero Trust or least privilege first for NHI risk?

Why This Matters for Security Teams

For NHI risk, the real decision is not zero trust versus least privilege as competing philosophies. Least privilege reduces the identity’s blast radius; Zero Trust tests every request, session, and pathway before allowing access. That pairing matters because NHIs are often over-scoped, reusable, and embedded in automation paths that security teams do not continuously inspect. NHI Mgmt Group research in the Ultimate Guide to NHIs reports that 97% of NHIs carry excessive privileges, which makes broad access the more immediate weakness. NIST also frames Zero Trust as a decision model that should continuously evaluate trust rather than assume it at the network edge in NIST SP 800-207 Zero Trust Architecture.

That is why many teams start with permission reduction before they layer on stronger request-time controls. If a service account can reach too many APIs, no amount of perimeter logic will fully contain the damage from compromise. For a broader NHI baseline, see Top 10 NHI Issues and the OWASP Non-Human Identity Top 10.

In practice, many security teams discover over-privileged NHIs only after a credential is reused across environments and the resulting access path is already active.

How It Works in Practice

The practical sequence is usually: identify the identities with the largest blast radius, reduce what they can touch, and then add Zero Trust controls that re-check context at each use. Least privilege does the first containment job by tightening scopes, separating shared accounts, and removing standing access that was granted for convenience. Zero Trust then improves the decision quality by evaluating the caller, workload, destination, and policy at request time rather than trusting prior network position alone. Current guidance suggests treating these as reinforcing controls, not substitutes.

For NHIs, this means mapping service accounts, API keys, workload tokens, and secrets to actual business tasks. If an identity only needs read access to one queue, it should not inherit write access to sibling systems. Where possible, use JIT credential provisioning and short-lived secrets so access expires with the task. NHI Mgmt Group’s Ultimate Guide to NHIs — Key Challenges and Risks explains why this matters, and the Guide to SPIFFE and SPIRE is useful for workload identity patterns that replace shared secrets with cryptographic proof of identity.

• Start with the NHIs that have cross-environment or admin-like reach.
• Replace broad RBAC grants with task-specific entitlements wherever possible.
• Use JIT, short TTLs, and automatic revocation for secrets and tokens.
• Layer Zero Trust policy checks at the resource, API, or service mesh boundary.

That approach aligns with NIST Cybersecurity Framework 2.0 and reduces the chance that one compromised NHI can move laterally through a service chain. These controls tend to break down when legacy applications require shared credentials, because entitlement cleanup and runtime policy enforcement become difficult to automate.

Common Variations and Edge Cases

Tighter least-privilege controls often increase operational overhead, so organisations have to balance faster containment against deployment friction and service reliability. That tradeoff is especially visible in CI/CD pipelines, shared platform accounts, and vendor-managed integrations, where access is often granted broadly to avoid breaking automation. Best practice is evolving, but there is no universal standard for this yet: some teams prioritise reducing standing privileges first, while others begin with Zero Trust policy enforcement on high-risk paths.

The exceptions are usually temporary, but they still need explicit control. For example, incident response accounts may need elevated access for a short window, and some workloads cannot yet move off long-lived secrets. In those cases, the right answer is not to abandon least privilege, but to document the exception, shrink its duration, and require stronger compensating controls. The Ultimate Guide to NHIs — Standards is a good reference point for aligning policy with current practice, while the OWASP NHI Top 10 helps teams track the failure modes that make both controls necessary.

Where organisations are still building basic inventory and ownership, Zero Trust without least privilege usually becomes a logging exercise rather than a risk reduction programme.

Related resources from NHI Mgmt Group

• When should organisations prioritise Zero Standing Privilege for non-human identities?
• Why do NHIs complicate zero trust and least privilege efforts?
• Why do non-human identities increase zero trust risk?
• Why do non-human identities complicate zero trust architecture?