How do access reviews need to change for machine identities?

Access reviews for machine identities should focus on purpose, owner, system reach, and whether the entitlement still exists for an active workload or integration. A reviewer cannot certify what they cannot contextualise, so reviews must show the business function behind the account rather than just a role name.

Why This Matters for Security Teams

Machine identity reviews are not a clerical version of user access certification. Service accounts, API keys, certificates, and workload tokens are often embedded in pipelines, integrations, and production automation, so a simple role check can miss whether the entitlement is still needed, still used, or still scoped safely. That is why the review question has to shift from “who has access?” to “what workload uses this access, for what purpose, and under what controls?”

This is especially urgent because NHI sprawl is now a mainstream exposure problem. NHI Mgmt Group notes that Ultimate Guide to NHIs reports only 5.7% of organisations have full visibility into their service accounts, while 97% of NHIs carry excessive privileges. In practice, review programs that were designed for human joiner-mover-leaver workflows often certify stale machine accounts for months because ownership is unclear and no one can prove whether the workload still exists. Current guidance from the OWASP Non-Human Identity Top 10 treats overprivilege and poor lifecycle governance as core NHI risks, not edge cases. In practice, many security teams discover the problem only after a dormant integration is reused or a forgotten token is exposed, rather than through a clean review cycle.

How It Works in Practice

Effective access reviews for machine identities need richer evidence than a name, a role, or a last-login timestamp. Reviewers should see the workload owner, the business function, the integration path, the systems reached, the credential type, and the rotation or expiration status. That allows the reviewer to answer whether the access is still justified by an active workload, and whether the privilege level is consistent with what the automation actually does.

A practical review packet usually includes:

• Workload or application name, plus the human or team accountable for it
• Purpose statement that ties the identity to a live business process
• Resource scope, including APIs, clusters, queues, databases, and third-party services
• Credential age, TTL, rotation history, and whether secrets are stored in a manager
• Evidence of recent use, but not as the only approval signal

For machine identities, “active” does not always mean “recently authenticated.” Some batch jobs run on long intervals, while other workloads only become visible during incident response. That is why reviews should be paired with lifecycle controls, as described in the NHI Lifecycle Management Guide, so access is revoked when the workload is decommissioned, paused, or replaced. The operational goal is to shorten the time between business change and entitlement removal, not to preserve a legacy permission because it “might still be needed.”

Best practice is also moving toward continuous or event-driven review triggers, such as ownership change, pipeline replacement, secret rotation failure, or certificate renewal miss. That aligns with identity governance patterns in the OWASP Non-Human Identity Top 10, which emphasises that static reviews alone do not keep pace with automated estates. These controls tend to break down when machine identities are hard-coded into legacy applications because ownership, usage, and revocation cannot be verified cleanly.

Common Variations and Edge Cases

Tighter review requirements often increase operational overhead, requiring organisations to balance stronger assurance against review fatigue and incomplete asset inventories. That tradeoff is real, especially where hundreds of short-lived integrations, vendor connections, or ephemeral build agents exist.

There is no universal standard for how much runtime evidence is enough for every machine identity. Current guidance suggests using risk-based tiers: high-value production identities should face more frequent review and stronger evidence, while low-risk test workloads may use lighter attestation if they are isolated and auto-expire. The same logic applies to shared credentials, where a single API key may support multiple pipelines. In those cases, the review should target the integration boundary, not just the key itself, because ownership is otherwise too diffuse to certify responsibly.

Another common edge case is certificate-based authentication. A certificate can be technically valid while the workload behind it is already retired, so the review must check both cryptographic validity and business relevance. The broader NHI risk picture in Ultimate Guide to NHIs — Key Challenges and Risks shows why this matters: visibility gaps and excessive privileges often persist even when formal review records look complete. The right test is not whether the identity exists, but whether it should still exist at all.

Related resources from NHI Mgmt Group

• How should security teams run access reviews for non-human identities?
• What does AI change in identity and access governance reviews?
• Who should be accountable for cloud PAM when human, machine, and AI identities all have access?
• How should security teams govern non-human identities that have persistent access?