How should security teams make least privilege reviews evidence-based?

Security teams should tie access reviews to observed usage, not just role assignments or manager memory. If an entitlement has not been used for a meaningful period, reviewers should treat it as a candidate for removal unless there is a documented operational need. Evidence-based reviews reduce privilege creep and make certification decisions easier to defend.

Why This Matters for Security Teams

Evidence-based least privilege reviews turn access certification from a memory exercise into an operational control. When reviewers rely on role labels, job titles, or manager approval alone, dormant entitlements stay in place and exceptions become invisible. That is especially risky for non-human identities, where secrets can outlive the workload that created them and over-privileged service accounts can quietly accumulate access. NHI Management Group research on the Ultimate Guide to NHIs — Key Challenges and Risks highlights how credential sprawl and over-privilege are recurring failure modes, while the OWASP Non-Human Identity Top 10 frames excessive privilege as a direct attack path, not just a compliance issue. A review is only defensible when it can show what was actually used, when, and by whom or by what system. In practice, many security teams discover privilege creep only after access has already been abused or inherited into a new workflow, rather than through intentional review design.

How It Works in Practice

The strongest reviews start with usage evidence, then test whether each entitlement is still justified. That means pulling logs from identity providers, cloud control planes, PAM systems, application audit trails, and workload telemetry, then matching them to the entitlement under review. The goal is to answer a simple question: did this identity actually need this access in the last review period, and is there a documented reason it still does?

A practical evidence-based workflow usually includes:

• Map each entitlement to observed activity, not just an assigned role.
• Set a meaningful inactivity threshold by system criticality and business cadence.
• Require reviewers to see logs, tickets, or change records before approving an exception.
• Separate human access from NHI access, because workloads often use short-lived tokens, service accounts, or API keys with very different usage patterns.
• Escalate repeated “no evidence found” cases to removal, not renewal.

For privileged access, this approach aligns well with Zero Trust thinking in NIST SP 800-207 Zero Trust Architecture, where access decisions should reflect current context rather than assumed trust. For NHIs, NHI Management Group’s JetBrains GitHub plugin token exposure example is a reminder that long-lived or unused credentials can become high-value liabilities even when nobody believes they are active. Current guidance suggests reviewers should prefer actual telemetry over manager recollection whenever the two disagree. These controls tend to break down in environments with poor logging, shared admin accounts, or shadow IT integrations because there is no reliable evidence trail to evaluate.

Common Variations and Edge Cases

Tighter evidence requirements often increase review effort, so teams must balance stronger assurance against the overhead of gathering and interpreting usage data. That tradeoff becomes more pronounced in large cloud estates, developer platforms, and agentic AI environments where access may be bursty, ephemeral, or delegated across multiple systems.

A few edge cases matter:

• Low-frequency access is not automatically suspicious. Break-glass accounts, quarterly jobs, and disaster recovery roles may show little activity by design, so the exception process must be explicit.
• Shared service identities need workload-specific evidence. For these, the relevant proof may be deployment records, CI/CD execution logs, or signed workload assertions rather than a named user session.
• Event-driven automation can look idle for long periods and then spike. Best practice is evolving here, and organisations should define activity windows that fit the workload lifecycle rather than forcing human-centric review cycles.
• For AI agents, the evidence standard should include task scope and runtime authorization context, not only credential presence, because an agent may perform many actions with a single short-lived token.

NHI Management Group’s research on the state of NHI security shows that only 1.5 out of 10 organisations are highly confident in securing NHIs, which helps explain why many reviews still rely on weak signals instead of observed behaviour. These reviews are most reliable when organisations accept that “unused” and “unneeded” are not always the same thing, then require evidence before keeping the exception alive.

Related resources from NHI Mgmt Group

• How should security teams implement access reviews to enforce least privilege?
• Why do NHIs complicate zero trust and least privilege efforts?
• How should security teams decide whether JIT access is safe for non-human identities?
• When does least privilege break down for machine identities?