How do organisations know whether access reviews are working?

Why This Matters for Security Teams

Access reviews are meant to prove that privileges still match business need, but for NHIs the signal is often weaker than teams expect. Service accounts, API keys, and other machine identities accumulate rights through project sprawl, integration changes, and emergency exceptions. When reviews only confirm what is already in the directory, they miss the real question: did the review reduce standing privilege, or simply re-approve it? That gap matters because NHIs are hard to see and easy to over-entitle; NHI Mgmt Group’s Ultimate Guide to NHIs notes that only 5.7% of organisations have full visibility into their service accounts.

The practical test is change over time. A review process that works should shrink the number of exceptions, shorten approval cycles for removals, and expose roles that no longer match actual workload behaviour. Guidance from the OWASP Non-Human Identity Top 10 and Ultimate Guide to NHIs — Key Challenges and Risks both points to the same operational truth: governance only matters if it changes entitlement outcomes. In practice, many security teams discover review failure only after an incident reveals that the same excess access was re-certified quarter after quarter.

How It Works in Practice

effective access reviews combine evidence, ownership, and enforcement. For NHIs, that means reviewing the workload identity itself, not just the owning team or the ticket history. Current best practice is to tie each account or secret to a named service, a business purpose, an expiry date, and a revocation path. If the review cannot answer who owns it, why it exists, when it expires, and what happens when it is no longer needed, the review is too shallow.

The mechanics usually look like this:

• Compare granted rights against the workload’s actual function and recent usage.
• Flag dormant accounts, stale secrets, and permissions that exceed the current task set.
• Require explicit justification for any exception, with a time bound.
• Revoke or downscope rights automatically when the review finds no current need.
• Track whether the same entitlement reappears in the next cycle, which is a sign that the underlying role model is broken.

For control design, pair review outcomes with lifecycle discipline from the NHI Lifecycle Management Guide and with the identity and secret hygiene called out in the 52 NHI Breaches Analysis. If a review approves long-lived secrets without rotation, it is not really validating need. The better pattern is to align reviews with automated removal, JIT credentials where possible, and short-lived access tied to workload identity, a model also echoed in the OWASP guidance. These controls tend to break down in environments with sprawling CI/CD pipelines and shared service accounts because ownership is unclear and revocation can disrupt multiple applications at once.

Common Variations and Edge Cases

Tighter review rules often increase operational overhead, requiring organisations to balance security gain against application uptime and support burden. That tradeoff is especially visible in legacy systems, third-party integrations, and flat infrastructure where one account backs many services. In those cases, a failed review may not mean the reviewer missed something; it may mean the environment cannot express least privilege cleanly yet.

There is no universal standard for how often every NHI should be reviewed. Current guidance suggests matching review frequency to privilege level, change rate, and blast radius. High-risk secrets and admin-grade service accounts deserve more frequent checks than low-impact internal jobs. Emerging practice also distinguishes between a human attestation review and a machine-enforced review outcome. The former can confirm business ownership, but only the latter can prove that access was actually removed.

Exception trends are one of the clearest health signals. If exceptions keep returning in the same form, the organisation likely needs to redesign roles, break apart shared identities, or move to short-lived credentials instead of re-carrying risk through every cycle. That is where access reviews stop being a compliance ritual and become evidence of control effectiveness.

Related resources from NHI Mgmt Group

• How do organisations know whether enterprise GRC architecture is actually working?
• How do organisations know whether AI identity monitoring is actually working?
• How do organisations know whether NHI attestation is actually working?
• How do organisations know whether identity visibility is actually improving?