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NIST SP 800-171 CUI Protection Center

03.01.22 — Publicly Accessible Content

Read the official CUI requirement and assessment content, then use the separately labeled Bare Metal Cyber perspective to connect it to implementation, evidence, and sustained operation.

1Source controls
3Assessment objectives

03.01 — Access Control · NIST SP 800-171 Revision 3

Active
Official NIST requirement content

Security requirement

  1. a.Train authorized individuals to ensure that publicly accessible information does not contain CUI.
  2. b.Review the content on publicly accessible systems for CUI and remove such information, if discovered.
Official NIST discussion

Discussion

In accordance with applicable laws, Executive Orders, directives, policies, regulations, standards, and guidelines, the public is not authorized to have access to nonpublic information, including CUI.

Bare Metal Cyber interpretation

Implementation perspective

Treat Publicly Accessible Content as a CUI protection outcome that must be reflected in the system boundary, documented implementation, operational behavior, and assessment evidence. Pay particular attention to approved identities, least privilege, remote access, information flow, and the full account lifecycle.

  1. Confirm the requirement is in scope for the CUI system components, services, users, and external connections being assessed.
  2. Resolve every organization-defined parameter through an approved governance and tailoring process.
  3. Map each clause of the requirement to an accountable owner, implementation mechanism, and evidence source.
  4. Verify that inherited and shared implementations are supported by current provider evidence and responsibility boundaries.
  5. Collect evidence during normal operation and review changes, exceptions, and deficiencies on a risk-based cadence.

Questions to ask

  • Which CUI assets, data flows, users, and services are protected by this requirement?
  • Which portions are implemented locally, inherited, shared, or not applicable, and what evidence supports that determination?
  • Do the system security plan, deployed configuration, operating process, and assessment evidence tell the same story?
  • What change, incident, or threshold should trigger reassessment?

Evidence and validation

  • access authorization and approval records
  • account inventories and entitlement exports
  • access review results
  • authentication and authorization logs

Common failure patterns

  • CUI access that exceeds mission need
  • shared or orphaned accounts
  • remote access paths outside the approved boundary
  • access reviews that cannot be reconciled to deployed permissions
Official NIST SP 800-171A content

Assessment objectives and methods

Assessment objectives (3)
  1. a.

    authorized individuals are trained to ensure that publicly accessible information does not contain CUI.

  2. b.

    the content on publicly accessible systems is reviewed for CUI.

  3. b.

    CUI is removed from publicly accessible systems, if discovered.

Official source-control relationships

Source NIST SP 800-53 controls

These controls are referenced by the official SP 800-171 Rev. 3 OSCAL record. Open the corresponding control pages for complete control text, enhancements, D3FEND mappings, and related learning.

Source controlAC-22Open SP 800-53 control →
Source record

Authoritative sources

Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST. The official publications, the responsible federal agency, and the governing contract or agreement determine applicability, tailoring, assessment depth, and required implementation.