SC-7(11)_restrict-incoming-communications-traffic

SC-7(11) Restrict Incoming Communications Traffic

Enhancement of: SC-7

High-Level Description

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

General source address validation techniques are applied to restrict the use of illegal and unallocated source addresses as well as source addresses that should only be used within the system. The restriction of incoming communications traffic provides determinations that source and destination address pairs represent authorized or allowed communications. Determinations can be based on several factors, including the presence of such address pairs in the lists of authorized or allowed communications, the absence of such address pairs in lists of unauthorized or disallowed pairs, or meeting more general rules for authorized or allowed source and destination pairs. Strong authentication of network addresses is not possible without the use of explicit security protocols, and thus, addresses can often be spoofed. Further, identity-based incoming traffic restriction methods can be employed, including router access control lists and firewall rules.

What to Check

• Verify SC-7(11) Restrict Incoming Communications Traffic is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for SC-7(11)
• 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(11) 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

Only allow incoming communications from [organization-defined] to be routed to [organization-defined].

Implementation Guidance

General source address validation techniques are applied to restrict the use of illegal and unallocated source addresses as well as source addresses that should only be used within the system. The restriction of incoming communications traffic provides determinations that source and destination address pairs represent authorized or allowed communications. Determinations can be based on several factors, including the presence of such address pairs in the lists of authorized or allowed communications, the absence of such address pairs in lists of unauthorized or disallowed pairs, or meeting more general rules for authorized or allowed source and destination pairs. Strong authentication of network addresses is not possible without the use of explicit security protocols, and thus, addresses can often be spoofed. Further, identity-based incoming traffic restriction methods can be employed, including router access control lists and firewall rules.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - SC-7(11)
• 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 (AC-3) reviewed