NIST SP 800-53 Rev. 5 AC-3(5) — Security-Relevant Information

What this control requires

Organizations must prevent access to security-relevant information except during secure, non-operable system states. This includes information such as access control lists, firewall filtering rules, and cryptographic key management data, which are critical to maintaining system security and privacy. This control supports the Governance capability within the Access Control family.

In plain English

Organizations must prevent access to security-relevant information except during secure, non-operable system states. In practice, this means you can prove you access management-level controls on a defined cadence.

Why it matters

SP 800-53 is the catalogue every U.S. federal authorisation (FedRAMP, FISMA, CMMC) and most regulated industries point at. A missing control surfaces as a Plan of Action & Milestones (POA&M) item that an Authorizing Official must approve before the Authority To Operate is granted or renewed.

This control is rated critical in the source catalogue. Treat gaps here as production incidents in the risk register, not housekeeping.

What an auditor looks for

A 3PAO (FedRAMP) or Independent Assessor (NIST RMF) tests against NIST SP 800-53A assessment procedures. For each control they expect a documented implementation that addresses every assessment objective (Examine, Interview, Test) and an implementation summary in the System Security Plan.

Within Access Control, the assessor will trace your implementation back to the catalogue reference (Control AC-3(5)) and look for objective evidence on the latest two assessment cycles.

How to implement

1. Write a short policy stating intent, scope and named owner.
2. Encode it as a platform guardrail — SCP, Azure Policy initiative, Organisation Policy, or repository policy.
3. Wire a monitoring signal that catches drift (CSPM rule, SIEM rule, scheduled query, Workspace alert) and ticket it.
4. Review on a documented cadence and capture the review in the risk register or compliance tracker.

Operational checklist

• Access. Document the trigger, the owner and the cadence.
• Security-Relevant. Document the trigger, the owner and the cadence.
• Information. Document the trigger, the owner and the cadence.
• Data. Document the trigger, the owner and the cadence.
• Review. Document the trigger, the owner and the cadence.
• Scope: management, access control, information, access control lists, cryptographic key management data, privacy, system, protection.

Evidence to collect

• Identity Scan. IAM / IdP exports — Entra ID, Okta, IAM Identity Center, Workspace directory — showing accounts, roles, MFA state and last sign-in.
• Infra Scan. Continuous infrastructure-posture telemetry — AWS Config, Azure Policy compliance, GCP Organisation Policy, Wiz / Prisma findings.

Identity analytics (Okta, SailPoint, Access Analyzer) demonstrates least-privilege. Focus: Security-Relevant Information.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

• NIST SP 800-171 Rev. 3 3.1.6 — Least Privilege - Privileged Accounts
• CIS Controls v8 6.8 — Define and Maintain Role-Based Access Control
• BSI C5:2020 IDM-08 — Confidentiality of authentication information
• ISO/IEC 27001:2022 A.5.18 — Access rights
• SOC 2 (2017 TSC) CC6.4 — Physical Access Controls

Related controls in NIST SP 800-53 Rev. 5

• Control AC-3(11) — Restrict Access To Specific Information Types
• Control AC-6(3) — Network Access To Privileged Commands
• Control AC-4(22) — Access Only
• Control AC-3(8) — Revocation Of Access Authorizations
• Control AC-6(2) — Non-Privileged Access For Nonsecurity Functions
• Control AC-17(6) — Protection Of Mechanism Information

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control AC-3(5)

Topics: governance riskidentity accessdata protectionidentity managementaccess reviewkey managementprivileged access