NHIs often exist in more places than a human account and can be created or copied without a clear lifecycle record. Access review becomes harder because reviewers need context about purpose, owner, privilege scope, and where the credential is embedded. Without that context, the review is administrative rather than governance-driven.
Why This Matters for Security Teams
Access review is already difficult for human accounts, but NHIs add a different problem: there are far more of them, they are often embedded in code, CI/CD pipelines, vaults, and third-party integrations, and their purpose is rarely obvious from the account name alone. The result is that reviewers are asked to validate entitlements without enough lifecycle or ownership context, which turns certification into a paperwork exercise instead of a control.
NHIMG research shows the scale of the issue: NHIs can outnumber human identities by 25x to 50x in modern enterprises, and only 5.7% of organisations report full visibility into their service accounts in the Ultimate Guide to NHIs. That lack of visibility means reviewers may be approving stale, duplicated, or over-privileged access without real evidence that the credential is still needed. The OWASP Non-Human Identity Top 10 frames this as an identity-class governance problem, not just a secrets hygiene problem.
In practice, many security teams discover the real inventory only after a breach, an audit finding, or a failed application dependency rather than through intentional identity governance.
How It Works in Practice
Human access review usually starts with a person, a manager, and a job function. NHI review starts with a credential that may belong to an application, a workload, a bot, or a pipeline step, and that credential may be copied across multiple systems. That means the reviewer needs to answer different questions: What is this identity for? Which workload owns it? Where is it used? What breaks if it is removed? If those answers are missing, the review cannot reliably determine whether access is justified.
Current guidance suggests treating NHIs as lifecycle-managed assets rather than static accounts. The NHI Lifecycle Management Guide emphasizes ownership, inventory, rotation, and offboarding as the basis for review. That is important because review outcomes depend on evidence: vault location, issuing system, last rotation date, expected runtime, and the consuming application. Without that evidence, a reviewer can only guess whether the access is still needed.
- Maintain a complete NHI inventory with owner, purpose, and system-of-record fields.
- Link each credential to one workload or approved business function.
- Tag entitlements by environment, privilege scope, and expiry date.
- Require automated attestations for credentials embedded in code, pipelines, or secrets managers.
- Revoke or rotate credentials that lack a named owner or a verified runtime dependency.
For many organisations, the best practice is evolving toward policy-based review using inventory data, runtime signals, and vault telemetry, rather than annual spreadsheet certification alone. NHIMG’s research on Top 10 NHI Issues highlights how duplication, overuse, and poor offboarding make manual review unreliable. These controls tend to break down when NHIs are duplicated across environments because ownership and blast radius become impossible to verify quickly.
Common Variations and Edge Cases
Tighter NHI review often increases operational overhead, requiring organisations to balance stronger governance against deployment speed and application uptime. That tradeoff becomes sharper when credentials are shared by multiple services, when legacy systems cannot support per-workload identities, or when third-party integrations expect long-lived API keys.
There is no universal standard for this yet, but current guidance suggests handling edge cases differently from human access. A shared service account should be treated as an exception with compensating controls, not as a normal recurring approval item. In high-churn engineering environments, review should focus on whether the credential is still active, where it is used, and whether it has a justified owner, rather than forcing reviewers to assess each downstream permission manually. The 2025 State of NHIs and Secrets in Cybersecurity report also shows why this matters operationally: 60% of NHIs are overused, which means one exposed identity can have a much larger blast radius than a single human account.
For audit teams, the practical goal is not perfect human-style certification. It is enough evidence to prove the NHI still has a valid business purpose, a named owner, and a bounded privilege scope at the time of review.
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-01 | Covers inventory and visibility gaps that make NHI reviews harder. |
| NIST CSF 2.0 | PR.AA-01 | Identity governance depends on knowing and validating identity lifecycle state. |
| NIST AI RMF | Governance and accountability are needed when autonomous systems create access complexity. |
Use AI RMF governance practices to assign accountability and review criteria for machine identities.
