NIST SP 800-53 Rev. 5 AC-4(13) — Decomposition Into Policy-Relevant Subcomponents

What this control requires

When transferring information between different security domains, organizations must decompose information into policy-relevant subcomponents for submission to policy enforcement mechanisms. This decomposition helps facilitate policy decisions regarding source, destination, certificates, classification, attachments, and other security- or privacy-related components. This control supports the Governance capability within the Access Control family.

In plain English

When transferring information between different security domains, organizations must decompose information into policy-relevant subcomponents for submission to policy enforcement mechanisms. 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 Access Control, the assessor will trace your implementation back to the catalogue reference (Control AC-4(13)) 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.
• Access. Document the trigger, the owner and the cadence.
• Information. Document the trigger, the owner and the cadence.
• Security. Document the trigger, the owner and the cadence.
• Data. Document the trigger, the owner and the cadence.
• Scope: management, enforcement, access control, information, privacy, domains, policy-relevant subcomponents, decisions.

Evidence to collect

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

Signed policy or standard documents the safeguard. Focus: Decomposition Into Policy-Relevant Subcomponents.

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.

• NIST SP 800-171 Rev. 3 3.1.9 — System Use Notification

Related controls in NIST SP 800-53 Rev. 5

• Control AC-4(1) — Object Security And Privacy Attributes
• Control AC-4(15) — Detection Of Unsanctioned Information
• Control AC-4(19) — Validation Of Metadata
• Control AC-4(8) — Security And Privacy Policy Filters
• Control AC-4(14) — Security Or Privacy Policy Filter Constraints
• Control AC-4(9) — Human Reviews

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control AC-4(13)

Topics: governance riskdata protectioncertificate managementpolicy managementprivacy management