They should prioritise both, but machine identities often deserve immediate attention because they are numerous, long-lived, and under-reviewed. If service accounts and keys are unmanaged, human access reviews alone will not close the largest exposure paths.
Why This Matters for Security Teams
Prioritising machine identities first is often the fastest way to reduce hidden exposure, because human access reviews only address one side of the identity estate. NHIs outnumber human identities by 25x to 50x in modern enterprises, and they are frequently long-lived, over-permissioned, and poorly inventoried. NHI Mgmt Group’s Ultimate Guide to NHIs shows that only 5.7% of organisations have full visibility into their service accounts, which means many teams are reviewing people while missing the credentials that actually move data and workloads.
The practical issue is sequencing. Human reviews remain important for joiner, mover, leaver hygiene and privileged role cleanup, but service accounts, API keys, certificates, and automation tokens can persist outside normal HR-driven processes. That is why guidance from the OWASP Non-Human Identity Top 10 and NHI lifecycle guidance increasingly treats machine identity governance as a separate workstream, not a subset of IAM. In practice, many security teams discover the largest access path only after a leaked key, stale service principal, or forgotten integration has already been abused.
How It Works in Practice
Security teams usually get better results by running two tracks in parallel: one for human access reviews and one for NHI discovery, ownership, rotation, and offboarding. The NHI track should start with inventory, because you cannot review what you cannot see. From there, assign business owners, confirm purpose, map each identity to the system it serves, and classify whether it is human-operated, workload-bound, or automation-driven. The NHI Lifecycle Management Guide is useful here because it frames lifecycle controls around creation, use, rotation, and retirement rather than treating credentials as static assets.
- Find machine identities in code, CI/CD, vaults, cloud consoles, and orchestration layers.
- Separate standing privileges from just-in-time access and remove anything without a current owner.
- Rotate secrets on a risk-based schedule, especially where keys never expire or are shared across systems.
- Use PAM, RBAC, and ZSP together, but do not assume RBAC alone can govern autonomous workloads.
Where possible, align review cadence with operational reality: high-risk secrets and privileged service accounts should be reviewed and rotated before broad human attestations are complete. The reason is simple. If the credential is persistent, widely distributed, or embedded in automation, a clean human access review can still leave the main blast radius untouched. Current guidance from the Ultimate Guide to NHIs — Key Challenges and Risks and the OWASP framework both point to this gap: identity risk is not just who has access, but what persists after the review ends. These controls tend to break down when credentials are hard-coded into build pipelines because revocation becomes a deployment problem, not an IAM task.
Common Variations and Edge Cases
Tighter machine identity controls often increase operational overhead, so organisations have to balance faster exposure reduction against engineering friction. That tradeoff is real in environments with legacy service accounts, shared automation users, or vendor-managed integrations. Best practice is evolving, but there is no universal standard for how quickly every NHI must be reviewed; risk-based prioritisation is more defensible than treating all identities equally.
Some environments also require exception handling. For example, third-party integrations may not support short-lived credentials, and some legacy platforms cannot rotate secrets without downtime. In those cases, the safer approach is compensating controls: isolate the workload, reduce privilege scope, add monitoring, and place the identity into a stricter attestation schedule. The 52 NHI Breaches Analysis is a useful reminder that many incidents are not caused by exotic attack chains, but by persistent credentials and missed ownership. The OWASP Non-Human Identity Top 10 also reinforces that standing secrets and weak lifecycle controls deserve priority over cosmetic review programs.
For most organisations, the right answer is not “machine identities instead of human reviews,” but “machine identities first where exposure is greatest, while human reviews continue on schedule.” That is the only way to reduce immediate risk without leaving governance gaps elsewhere.
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 Zero Trust (SP 800-207) set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-03 | Directly addresses rotation and lifecycle gaps in machine identities. |
| NIST CSF 2.0 | PR.AC-4 | Least-privilege access review is central to both human and machine identities. |
| NIST Zero Trust (SP 800-207) | SC-4 | Zero Trust requires continuous verification of identities and access paths. |
Treat NHIs as continuously verified workloads and limit trust to explicit, current context.
Related resources from NHI Mgmt Group
- How should security teams run access reviews for non-human identities?
- How should security teams govern non-human identities that have persistent access?
- How should organisations assign ownership to machine identities?
- How should organisations govern non-human identities as part of operational resilience?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on May 30, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
