sa-4-9-functions-ports-protocols-and-services-in-use

name	SA-4(9)_functions-ports-protocols-and-services-in-use
description	Require the developer of the system, system component, or system service to identify the functions, ports, protocols, and services intended for organi
category	configuration
version	5.2.0
author	cyberstrike-official
tags	["nist","sp800-53","rev5","sa-4-9","sa","enhancement"]
tech_stack	["any"]
cwe_ids	["CWE-16"]
chains_with	["CM-7","SA-9"]
prerequisites	["SA-4"]
severity_boost	{"CM-7":"Chain with CM-7 for comprehensive security coverage","SA-9":"Chain with SA-9 for comprehensive security coverage"}

SA-4(9) Functions, Ports, Protocols, and Services in Use

Enhancement of: SA-4

High-Level Description

Family: System and Services Acquisition (SA) Framework: NIST SP 800-53 Rev 5

The identification of functions, ports, protocols, and services early in the system development life cycle (e.g., during the initial requirements definition and design stages) allows organizations to influence the design of the system, system component, or system service. This early involvement in the system development life cycle helps organizations avoid or minimize the use of functions, ports, protocols, or services that pose unnecessarily high risks and understand the trade-offs involved in blocking specific ports, protocols, or services or requiring system service providers to do so. Early identification of functions, ports, protocols, and services avoids costly retrofitting of controls after the system, component, or system service has been implemented. SA-9 describes the requirements for external system services. Organizations identify which functions, ports, protocols, and services are provided from external sources.

What to Check

• Verify SA-4(9) Functions, Ports, Protocols, and Services in Use is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for SA-4(9)
• Verify enhancement builds upon base control SA-4

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SA-4(9) 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
Manual Review	Documentation and interview-based	N/A

Remediation Guide