NIST SP 800-53 Rev. 5 RA-5(4) — Discoverable Information

What this control requires

Identify system information that can be obtained externally--without breaching the system--and apply corrective actions to reduce exposure or value to adversaries. This control supports the Exposure Assessment Module capability within the Risk Assessment family.

In plain English

Identify system information that can be obtained externally--without breaching the system--and apply corrective actions to reduce exposure or value to adversaries. In practice, this means you can prove you policy 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.

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 Risk Assessment, the assessor will trace your implementation back to the catalogue reference (Control RA-5(4)) and look for objective evidence on the latest two assessment cycles.

How to implement

Policy Management

Docs. Keep each policy in version-controlled Markdown alongside the code that implements it; ship a signed PDF snapshot at each annual review and link the SHA into the SoA.

Operational checklist

• Policy. Document the trigger, the owner and the cadence.
• Information. Document the trigger, the owner and the cadence.
• System. Document the trigger, the owner and the cadence.
• Control. Document the trigger, the owner and the cadence.
• Identify. Document the trigger, the owner and the cadence.
• Scope: management, actions, information, system, assessment, capability, policy.

Evidence to collect

• Policy Document. A signed and version-controlled policy / standard / procedure document.

Signed policy or standard documents the safeguard. Focus: Discoverable Information.

Common pitfalls

• Policies that no engineer has read; the version in Confluence drifts from the version that's actually being enforced.

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.

• ISO/IEC 27001:2022 A.5.13 — Labelling of information
• NIST SP 800-171 Rev. 3 3.11.4 — Risk Response
• HIPAA (45 CFR Part 164) 164.308(a)(5)(i) — Security Awareness and Training
• SOC 2 (2017 TSC) C1.2 — Confidential Information Disposal
• BSI C5:2020 SP-01 — Documentation, communication and provision of policies and instructions

Related controls in NIST SP 800-53 Rev. 5

• Control RA-5(2) — Update Vulnerabilities To Be Scanned
• Control RA-2 — Security Categorization
• Control CP-7(2) — Accessibility
• Control SI-2(3) — Time To Remediate Flaws And Benchmarks For Corrective Actions
• Control SI-7(3) — Centrally Managed Integrity Tools
• Control SI-7(5) — Automated Response To Integrity Violations

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control RA-5(4)

Topics: governance riskpolicy management