AC-4(2)_processing-domains

AC-4(2) Processing Domains

Enhancement of: AC-4

High-Level Description

Family: Access Control (AC) Framework: NIST SP 800-53 Rev 5

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.

What to Check

• Verify AC-4(2) Processing Domains is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for AC-4(2)
• Verify enhancement builds upon base control AC-4

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AC-4(2) implementation details. Verify the organization has documented how this control is satisfied.

Step 2: Validate Implementation

# For cloud environments, use cloud-audit-mcp tools
# For on-premises, review system configurations directly

# Example: Check if account management policies exist
grep -r "account.management\|access.control" /etc/security/ 2>/dev/null

Step 3: Test Operating Effectiveness

Verify the control is actively functioning, not just documented. Check logs, configurations, and operational evidence.

Tools

Remediation Guide

Control Statement

Use protected processing domains to enforce [organization-defined] as a basis for flow control decisions.

Implementation 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.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - AC-4(2)
• NIST SP 800-53A Rev 5 (Assessment Procedures)
• NIST SP 800-53 Rev 5 Full Catalog

Checklist

• Control documented in SSP
• Implementation evidence collected
• Operating effectiveness validated
• Continuous monitoring in place
• Related controls (SC-39) reviewed