SC-7(29)_separate-subnets-to-isolate-functions

SC-7(29) Separate Subnets to Isolate Functions

Enhancement of: SC-7

High-Level Description

Family: System and Communications Protection (SC) Framework: NIST SP 800-53 Rev 5

Separating critical system components and functions from other noncritical system components and functions through separate subnetworks may be necessary to reduce susceptibility to a catastrophic or debilitating breach or compromise that results in system failure. For example, physically separating the command and control function from the in-flight entertainment function through separate subnetworks in a commercial aircraft provides an increased level of assurance in the trustworthiness of critical system functions.

What to Check

• Verify SC-7(29) Separate Subnets to Isolate Functions is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for SC-7(29)
• Verify enhancement builds upon base control SC-7

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SC-7(29) 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

Implement [organization-defined] separate subnetworks to isolate the following critical system components and functions: [organization-defined].

Implementation Guidance

Separating critical system components and functions from other noncritical system components and functions through separate subnetworks may be necessary to reduce susceptibility to a catastrophic or debilitating breach or compromise that results in system failure. For example, physically separating the command and control function from the in-flight entertainment function through separate subnetworks in a commercial aircraft provides an increased level of assurance in the trustworthiness of critical system functions.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - SC-7(29)
• 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 (none) reviewed