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AC-4(2) AC · Access Control

Processing Domains

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Requirements NIST SOURCE

Use protected processing domains to enforce [information flow control policies] as a basis for flow control decisions.

Discussion (NIST Supplemental Guidance)

Protected processing domains within systems are processing spaces that have controlled interactions with other processing spaces, enabling control of information flows between these spaces and to/from information objects. A protected processing domain can be provided, for example, by implementing domain and type enforcement. In domain and type enforcement, system processes are assigned to domains, information is identified by types, and information flows are controlled based on allowed information accesses (i.e., determined by domain and type), allowed signaling among domains, and allowed process transitions to other domains.

Implementation Guidance

Engineering Interpretation

Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.

No engineering interpretation has been authored for AC-4(2) yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.

Assessment

NIST SP 800-53A REV 5.2.0

Assessment Objectives

  1. information flow control policies to be enforced by use of protected processing domains are defined;
  2. protected processing domains are used to enforce <AC-04(02)_ODP information flow control policies> as a basis for flow control decisions.

Examine

[SELECT FROM: Access control policy; information flow control policies; procedures addressing information flow enforcement; system design documentation; system security architecture and associated documentation; system configuration settings and associated documentation; system audit records; system security plan; other relevant documents or records].

Interview

[SELECT FROM: System/network administrators; organizational personnel with information security responsibilities].

Test

[SELECT FROM: Mechanisms implementing information flow enforcement policy].

Overlays

Showing the OT/ICS overlay for the parent control AC-4 — see the AC-4(2) entries within each baseline below.

OT/ICS Overlay SP 800-82r3

NIST SP 800-82r3 Appendix F, Table 22. Blank baseline means the control/control enhancement is not selected in that initial OT baseline.

LOW

Not applicable at this tier.

MODERATE

  • Base control: Included (matches standard baseline)

HIGH

  • Base control: Included (matches standard baseline)
  • Included: (4)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for AC-4(2). This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.

Learn more about STIG/CCI integration →

Evidence

Potential Evidence — Derived

Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.

Policy

  • Access control policy
  • information flow control policies
  • system security plan

Configuration

  • system design documentation
  • system security architecture and associated documentation
  • system configuration settings and associated documentation

Testing

  • Mechanisms implementing information flow enforcement policy

Other Records

  • procedures addressing information flow enforcement
  • system audit records
  • other relevant documents or records