What breaks when organisations rely on manual access reviews and ad hoc privilege removal?

Why This Matters for Security Teams

Manual access reviews are often treated as a safety net, but for non-human identities the net usually has holes. Service accounts, API keys, and agent credentials change too quickly for periodic attestation to keep up, especially when teams rely on email approvals and spreadsheet-based cleanup. That delay matters because privilege does not expire just because a reviewer signed off last quarter.

The practical risk is straightforward: excessive access remains active long after the business need ends, and the organisation loses confidence in the evidence trail. NHIMG research shows that 97% of NHIs carry excessive privileges, and only 5.7% of organisations have full visibility into their service accounts in the Ultimate Guide to NHIs. That is why a review process alone is not a control if revocation is slow or incomplete. The baseline expectation in OWASP Non-Human Identity Top 10 and NIST SP 800-53 Rev. 5 is that access decisions and revocation must be actionable, not merely documented. In practice, many security teams discover the gap only after an audit request or an incident has already exposed stale privilege.

How It Works in Practice

The failure mode is usually not the review itself but the gap between review and enforcement. Teams identify excess privilege during an access certification, then route removal through tickets, approvals, and manual owner checks. By the time access is removed, the account may have already been used for data access, lateral movement, or automated task chaining. For NHI operations, that lag is especially dangerous because identities are often shared across pipelines, deployments, and scheduled jobs.

Current best practice is to pair periodic review with continuous control enforcement. That means inventorying every workload identity, mapping ownership, and tying access to lifecycle events such as deployment, decommissioning, or role change. For higher-risk access, organisations increasingly use just-in-time elevation, short-lived secrets, and automated revocation so that privilege exists only when a task requires it. The Ultimate Guide to NHIs - Key Challenges and Risks highlights how gaps in visibility and rotation turn routine administration into persistent exposure.

Operationally, the most effective programs do three things:

• Use authoritative inventory so reviewers see all active NHIs, not only the ones already documented.
• Automate offboarding and revocation at source systems, secrets managers, and CI/CD tools.
• Require evidence that privilege was removed, not just approved for removal.

This aligns with the control intent in NIST and OWASP guidance, but it also reflects what actually works when accounts are ephemeral, shared, or embedded in automation. These controls tend to break down in distributed environments with many unmanaged service accounts because ownership is unclear and revocation cannot be reliably propagated across all systems.

Common Variations and Edge Cases

Tighter revocation often increases operational overhead, requiring organisations to balance risk reduction against deployment speed and service stability. That tradeoff becomes visible in environments that rely on shared runtime accounts, vendor-managed integrations, or legacy applications that cannot tolerate frequent credential changes.

There is no universal standard for this yet, but current guidance suggests treating these cases as exceptions that need compensating controls, not as justification for permanent standing privilege. Where automation is limited, reviewers should demand stronger evidence of business need, shorter review intervals, and explicit expiry dates. Where service accounts cannot be rotated cleanly, organisations should prioritise segmentation, scope reduction, and vault-backed secrets over manual exception handling.

NHIMG’s NHI Lifecycle Management Guide is useful here because it frames revocation as a lifecycle event rather than a one-time administrative task. That matters in environments where temporary access becomes de facto permanent because nobody owns the cleanup. The bigger issue is not whether reviewers noticed the privilege, but whether the organisation can remove it before the next automated action uses it. In many breach investigations, the account was already over-privileged long before the review cycle caught up.

Related resources from NHI Mgmt Group

• What breaks when organisations rely on manual user access reviews and onboarding processes?
• What breaks when organisations rely on manual monitoring for file access governance?
• What breaks when organisations rely on manual access reviews for NHIs?
• What breaks when organisations rely on ad hoc access control for APIs and AI agents?