They often apply human review logic to machine access, which misses the speed and persistence of non-human entitlements. Access reviews work best when they focus on exceptions, stale accounts, and privileged integrations that no longer match the current business process. Otherwise, the evidence becomes outdated before the next cycle.
Why This Matters for Security Teams
Access reviews for machine identities fail when teams treat service accounts, API keys, certificates, and agent credentials like human user accounts. Machines do not have a neat quarterly usage pattern, and their entitlements often outlive the business process that created them. That is why non-human identity governance has to focus on lifecycle, ownership, and revocation, not just spreadsheet attestation. NHI Mgmt Group notes that only 5.7% of organisations have full visibility into their service accounts in the Ultimate Guide to NHIs.
The real risk is that stale machine access tends to persist silently across CI/CD pipelines, integrations, and cloud workloads. The OWASP Non-Human Identity Top 10 treats weak lifecycle control as a core failure mode because access reviews that only ask whether an account exists miss whether it is still needed, still privileged, or still reachable. In practice, many security teams encounter compromise only after a stale secret or overprivileged integration has already been abused, rather than through intentional review.
How It Works in Practice
Effective machine identity reviews start with inventory, ownership, and usage context. That means mapping each identity to a workload, pipeline, integration, or agent; identifying who can approve changes; and checking whether the entitlement is still required by the current process. Reviews should prioritise exceptions, privileged service accounts, stale credentials, and secrets that are embedded in code or deployment tooling. The NHI Lifecycle Management Guide is useful here because lifecycle state is often a better review boundary than a calendar date.
In mature programs, review evidence should include last-used timestamps, rotation age, blast radius, and dependency mapping. That lets reviewers answer a practical question: if this identity were removed today, what would break? For NHI-specific controls, the right frame is usually not “does a manager still approve it?” but “does the workload still need it, and is the entitlement scoped to the minimum viable access?” Current guidance suggests pairing periodic attestation with automated signals from secrets managers, cloud IAM, and deployment systems. The Ultimate Guide to NHIs — Key Challenges and Risks is a good reference for the common failure patterns.
- Review by workload, not by person.
- Flag identities with no recent usage, no owner, or no documented dependency.
- Prioritise privileged integrations, long-lived secrets, and externally exposed credentials.
- Trigger revocation when the process changes, not only when the next review cycle arrives.
These controls tend to break down in fast-moving CI/CD environments because access is created and consumed faster than manual reviewers can validate it.
Common Variations and Edge Cases
Tighter machine access review often increases operational overhead, so organisations have to balance assurance against pipeline friction and service uptime. That tradeoff is real, especially where teams rely on legacy automation, embedded certificates, or third-party integrations that cannot easily be reissued on demand. Best practice is evolving, but the current direction is clear: use continuous signals to reduce the number of items that need manual attestation and reserve human review for exceptions with real risk.
One common edge case is ephemeral compute. Short-lived jobs, containers, and agentic workflows may not leave a useful review trail if the program only snapshots entitlements quarterly. Another is delegated access through third parties, where an apparently harmless connector can become a high-value path into production data. The OWASP guidance and broader NHI lifecycle thinking both point to the same conclusion: if an identity cannot be tied to a current owner, purpose, and revocation path, it should not survive review by default. In practice, the hardest misses show up where credentials are “technically valid” but operationally orphaned.
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 address the attack and risk surface, while NIST CSF 2.0 and NIST AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-03 | Access reviews must catch stale or overprivileged non-human credentials. |
| NIST CSF 2.0 | PR.AC-1 | Machine identity review is an access control governance activity. |
| NIST AI RMF | Autonomous or automated workloads need ongoing governance and accountability. |
Review NHI entitlements by workload and revoke credentials that no longer match purpose.
