NIST SP 800-53 Rev. 5 CP-6(3) — Accessibility

What this control requires

Assess accessibility issues to alternate storage sites during area-wide disruptions and define mitigation actions, such as additional dispersed sites or physical retrieval plans. This control supports the Accessibility capability within the Contingency Planning family.

In plain English

Assess accessibility issues to alternate storage sites during area-wide disruptions and define mitigation actions, such as additional dispersed sites or physical retrieval plans. 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.

This control is rated high. Auditors expect a named owner, a remediation SLA, and a tooling artefact that evidences continuous operation.

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 Contingency Planning, the assessor will trace your implementation back to the catalogue reference (Control CP-6(3)) and look for objective evidence on the latest two assessment cycles.

How to implement

Physical Security

Inheritance. For cloud-only operations, inherit physical controls from the provider's SOC 2 / ISO 27001 report and document the inheritance in the SoA.

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.
• Security. Document the trigger, the owner and the cadence.
• Physical. Document the trigger, the owner and the cadence.
• Additional. Document the trigger, the owner and the cadence.
• Storage. Document the trigger, the owner and the cadence.
• Scope: management, actions, alternate storage, physical retrieval plans, capability, security policy, assess.

Evidence to collect

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

Signed policy or standard documents the safeguard. Focus: Accessibility.

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.7.3 — Securing offices, rooms and facilities
• HIPAA (45 CFR Part 164) 164.308(a)(5)(i) — Security Awareness and Training
• BSI C5:2020 SP-01 — Documentation, communication and provision of policies and instructions
• NIST SP 800-171 Rev. 3 3.13.10 — Cryptographic Key Establishment and Management

Related controls in NIST SP 800-53 Rev. 5

• Control CP-7(2) — Accessibility
• Control CP-8(3) — Separation Of Primary And Alternate Providers
• Control RA-6 — Technical Surveillance Countermeasures Survey
• Control CP-7(4) — Preparation For Use
• Control CP-7(6) — Inability To Return To Primary Site
• Control CP-2(6) — Alternate Processing And Storage Sites

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control CP-6(3)

Topics: governance riskphysical securitypolicy management