Delayed reviews let stale access, copied roles, and excess permissions survive across plants, vendors, and cloud systems. In manufacturing, that is especially dangerous because access often spans multiple operational environments and temporary staff changes quickly. The longer the review cycle, the more likely it is that access no longer matches business need when someone finally checks it.
Why This Matters for Security Teams
Delayed access reviews are not just an audit hygiene problem in manufacturing. They let stale accounts, copied entitlements, and vendor access persist across plants, OT environments, cloud services, and shared support systems long after the business need has changed. That matters because manufacturing access is often time-sensitive, cross-functional, and temporary by design, which makes old permissions easy to overlook and hard to spot once they drift.
The risk is amplified when those permissions belong to non-human identities and service accounts, where the real blast radius is often hidden until something fails. NHIMG research shows that 97% of NHIs carry excessive privileges and only 5.7% of organisations have full visibility into their service accounts, which is why the Ultimate Guide to NHIs treats lifecycle control as foundational. OWASP also flags identity sprawl and privilege creep in the OWASP Non-Human Identity Top 10 as a recurring security failure mode.
In practice, many security teams encounter unnecessary production exposure only after a contractor, engineer, or integration still has access that should have been removed months earlier.
How It Works in Practice
Manufacturing environments create review delays for predictable reasons: shift changes, seasonal staffing, plant-specific exceptions, and operational pressure to avoid interrupting production. When access reviews happen quarterly or semi-annually, the review becomes a retrospective paperwork exercise instead of a live control. By the time an approver confirms that an account is still valid, the role may already have changed, the vendor may have rotated staff, or the service account may be embedded in a workflow that no one wants to disturb.
That gap is especially dangerous for NHIs because access often survives without an obvious human owner. A robot cell integration account, an MES-to-ERP connector, or a CI/CD token can keep working indefinitely unless someone actively checks ownership, purpose, scope, and expiry. NHIMG recommends treating the review as part of lifecycle management, not as a separate compliance event, and the NHI Lifecycle Management Guide is explicit that review cadence should be tied to change events, not calendar convenience.
- Review by business function, plant, vendor, and system tier instead of by directory list alone.
- Separate human access from service accounts, API keys, certificates, and machine-to-machine tokens.
- Require an owner for every privileged account and every integration credential.
- Compare current access to current job duty, current contract status, and current machine purpose.
- Revoke or step up to JIT access when the need is temporary rather than permanent.
NIST’s Cybersecurity Framework 2.0 supports this approach by linking access governance to ongoing risk management rather than one-time approval. These controls tend to break down when manufacturing identities are duplicated across OT, IT, and vendor-managed tooling because ownership and usage data are fragmented across systems.
Common Variations and Edge Cases
Tighter review cycles often increase operational overhead, so organisations have to balance faster revocation against production continuity and maintenance windows. That tradeoff is most visible in plants that run legacy OT systems, use shared workstations, or depend on third-party service engineers who need emergency access.
Current guidance suggests that the right answer is not simply “review more often,” but “review based on risk and change rate.” High-risk privileged accounts, vendor access, and machine credentials should be reviewed more frequently than low-risk standard accounts. Where there is no universal standard for this yet, best practice is evolving toward event-driven review triggers, such as role change, contract expiry, asset decommissioning, or secrets rotation. For deeper context on how stale secrets and overprivileged NHIs compound this problem, see 52 NHI Breaches Analysis and Top 10 NHI Issues.
In plants with outsourced operations or heavily automated lines, delayed reviews also miss shadow access created by shared credentials, vendor jump hosts, and scripts that were “temporary” but never retired. In those environments, the control fails when review evidence exists but no one can reliably map the entitlement back to the real-world machine, process, or person using it.
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-03 | Addresses stale and overprivileged non-human identities created by delayed reviews. |
| NIST CSF 2.0 | PR.AA-01 | Identity governance depends on timely validation of who or what is authorized. |
| NIST AI RMF | Risk governance applies when automated systems keep access beyond intended use. |
Use risk management processes to identify, monitor, and remediate access drift across automated and human workflows.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on June 24, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
