Access reviews matter because CMMC readiness depends on proving that only authorised people can reach CUI and that access changes are controlled. If reviews are inconsistent, the organisation may still function, but it cannot reliably demonstrate governance. That becomes a problem during assessment and in prime-contractor scrutiny.
Why This Matters for Security Teams
Access reviews are not a paperwork exercise when CMMC is in scope. They are evidence that the organisation can identify who has access to Controlled Unclassified Information, justify that access, and remove entitlements that no longer match the person’s role. That matters because assessors look for repeatable governance, not informal assurances. The control intent aligns closely with access governance expectations in NIST SP 800-53 Rev 5 Security and Privacy Controls.
Teams often underestimate how many access paths exist outside the core identity system. Shared service accounts, vendor access, cloud entitlements, and application-specific permissions can all create exposure even when the directory looks clean. In CMMC readiness work, access review evidence needs to show both coverage and action: who was reviewed, what was removed, who approved exceptions, and when follow-up occurred. That is especially important where privileged access or machine identities can reach systems that store, process, or transmit CUI.
In practice, many security teams encounter access review failures only after an assessor asks for evidence, rather than through intentional governance.
How It Works in Practice
effective access reviews start with a complete inventory of access-bearing identities and systems. The review scope should include employees, contractors, administrators, service accounts, API keys, and other non-human identities where they can reach CUI or support systems that do. For CMMC readiness, the strongest evidence is not a one-time attestation but a documented process with clear ownership, defined frequency, and remediation tracking.
A practical review usually follows a few steps:
- Define the scope by system, data classification, and business unit.
- Map each user or identity to an approved business need and role.
- Validate privileged access separately, since admin rights carry higher risk.
- Remove dormant, excessive, or unapproved access and record the change.
- Retain review outputs, approvals, exceptions, and remediation tickets as audit evidence.
Security teams should also distinguish between recertification and entitlement cleanup. A review that only re-approves existing access without verifying role fit does not meaningfully reduce risk. Best practice is evolving toward continuous signals, such as HR status changes, joiner-mover-leaver events, and PAM session data, but there is no universal standard for replacing periodic access reviews entirely. Assessors generally expect the organisation to show that reviews are risk-based, not merely calendar-driven.
Where non-human identities are involved, access review scope should be broader than many teams first assume. Secrets, tokens, certificates, and automation accounts can silently retain access long after the original project ends. The OWASP Non-Human Identity Top 10 is useful here because it highlights how machine identities become governance blind spots when ownership, lifecycle, and revocation are weak. These controls tend to break down in fast-moving DevOps environments because access is created through code and automation faster than manual review cycles can track.
Common Variations and Edge Cases
Tighter access review programs often increase administrative overhead, requiring organisations to balance stronger assurance against review fatigue and operational delay. That tradeoff becomes visible in environments with large contractor populations, many business applications, or frequent role changes. In those cases, current guidance suggests using risk-based prioritisation rather than treating every entitlement as equal.
There are several edge cases that matter in CMMC programs. First, inherited access through groups or nested roles can hide the real privilege level unless the review tool expands effective permissions. Second, application owners may approve access that conflicts with corporate policy if identity governance is disconnected from PAM or HR sources of truth. Third, machine identities may not appear in standard user review workflows, which creates an exception gap unless they are explicitly included.
For organisations supporting multiple compliance obligations, access review evidence may also need to map to broader control families, especially when CUI systems overlap with regulated data or externally managed services. The key is consistency: a review process that is documented, repeatable, and able to show remediation is much more defensible than one that depends on individual manager memory. Where ephemeral infrastructure, outsourced operations, or legacy applications lack reliable identity inventory, access review guidance degrades quickly because reviewers cannot confirm what actually has access.
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 surface, NIST CSF 2.0 and NIST SP 800-53 Rev 5 set the technical controls, and DORA define the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | PR.AC | Access governance supports verified, least-privilege access to sensitive data. |
| NIST SP 800-53 Rev 5 | AC-2 | Account lifecycle control underpins periodic access recertification and removal. |
| OWASP Non-Human Identity Top 10 | Machine identities can retain undocumented access outside human review workflows. | |
| DORA | Operational resilience depends on provable access governance and change control. |
Tie access review results to remediation tracking so access risk is reduced and evidence is defensible.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on July 11, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
