sc-7-4-external-telecommunications-services

name	SC-7(4)_external-telecommunications-services
description	Implement a managed interface for each external telecommunication service;
category	configuration
version	5.2.0
author	cyberstrike-official
tags	["nist","sp800-53","rev5","sc-7-4","sc","enhancement"]
tech_stack	["aws","azure","gcp","linux","windows","network"]
cwe_ids	["CWE-311"]
chains_with	["AC-3","SC-8","SC-20","SC-21","SC-22"]
prerequisites	["SC-7"]
severity_boost	{"AC-3":"Chain with AC-3 for comprehensive security coverage","SC-8":"Chain with SC-8 for comprehensive security coverage","SC-20":"Chain with SC-20 for comprehensive security coverage"}

SC-7(4) External Telecommunications Services

Enhancement of: SC-7

High-Level Description

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

External telecommunications services can provide data and/or voice communications services. Examples of control plane traffic include Border Gateway Protocol (BGP) routing, Domain Name System (DNS), and management protocols. See SP 800-189 for additional information on the use of the resource public key infrastructure (RPKI) to protect BGP routes and detect unauthorized BGP announcements.

What to Check

• Verify SC-7(4) External Telecommunications Services is documented in SSP
• Validate all 8 control requirements are implemented
• Confirm control is operating effectively
• Review evidence of continuous monitoring for SC-7(4)
• 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(4) 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

Tool	Purpose	Usage
cloud-audit-mcp	Check encryption and network controls	cloud_audit_encryption
nmap	Network scanning	nmap -sV --script ssl-enum-ciphers

Remediation Guide

Control Statement

Implement a managed interface for each external telecommunication service; Establish a traffic flow policy for each managed interface; Protect the confidentiality and integrity of the information being transmitted across each interface; Document each exception to the traffic flow policy with a supporting mission or business need and duration of that need; Review exceptions to the traffic flow policy [organization-defined] and remove exceptions that are no longer supported by an explicit mission or business need; Prevent unauthorized exchange of control plane traffic with external networks; Publish information to enable remote networks to detect unauthorized control plane traffic from internal networks; and Filter unauthorized control plane traffic from external networks.