# SA-9(2)_identification-of-functions-ports-protocols-and-services

> Require providers of the following external system services to identify the functions, ports, protocols, and other services required for the use of su

- Skill: `cyberstrikeus/sa-9-2-identification-of-functions-ports-protocols-and-servi` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/sa-9-2-identification-of-functions-ports-protocols-and-servi`
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- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/sa-9-2-identification-of-functions-ports-protocols-and-servi

---


# SA-9(2) Identification of Functions, Ports, Protocols, and Services

> **Enhancement of:** SA-9

## High-Level Description

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

Information from external service providers regarding the specific functions, ports, protocols, and services used in the provision of such services can be useful when the need arises to understand the trade-offs involved in restricting certain functions and services or blocking certain ports and protocols.

## What to Check

- [ ] Verify SA-9(2) Identification of Functions, Ports, Protocols, and Services is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for SA-9(2)
- [ ] Verify enhancement builds upon base control SA-9

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SA-9(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

| Tool          | Purpose                           | Usage |
| ------------- | --------------------------------- | ----- |
| Manual Review | Documentation and interview-based | N/A   |

## Remediation Guide

### Control Statement

Require providers of the following external system services to identify the functions, ports, protocols, and other services required for the use of such services: [organization-defined].

### Implementation Guidance

Information from external service providers regarding the specific functions, ports, protocols, and services used in the provision of such services can be useful when the need arises to understand the trade-offs involved in restricting certain functions and services or blocking certain ports and protocols.

## Risk Assessment

| Finding                                                                             | Severity | Impact                                     |
| ----------------------------------------------------------------------------------- | -------- | ------------------------------------------ |
| SA-9(2) Identification of Functions, Ports, Protocols, and Services not implemented | Medium   | System and Services Acquisition            |
| SA-9(2) partially implemented                                                       | Low      | Incomplete System and Services Acquisition |

## CWE Categories

| CWE ID | Title         |
| ------ | ------------- |
| CWE-16 | Configuration |

## References

- [NIST SP 800-53 Rev 5 - SA-9(2)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=sa-9.2)
- [NIST SP 800-53A Rev 5 (Assessment Procedures)](https://csrc.nist.gov/pubs/sp/800/53/a/r5/final)
- [NIST SP 800-53 Rev 5 Full Catalog](https://csrc.nist.gov/pubs/sp/800/53/r5/upd1/final)

## Checklist

- [ ] Control documented in SSP
- [ ] Implementation evidence collected
- [ ] Operating effectiveness validated
- [ ] Continuous monitoring in place
- [ ] Related controls (CM-6, CM-7) reviewed