# SA-4(1)_functional-properties-of-controls

> Require the developer of the system, system component, or system service to provide a description of the functional properties of the controls to be i

- Skill: `cyberstrikeus/sa-4-1-functional-properties-of-controls` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/sa-4-1-functional-properties-of-controls`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/sa-4-1-functional-properties-of-controls/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/sa-4-1-functional-properties-of-controls

---


# SA-4(1) Functional Properties of Controls

> **Enhancement of:** SA-4

## High-Level Description

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

Functional properties of security and privacy controls describe the functionality (i.e., security or privacy capability, functions, or mechanisms) visible at the interfaces of the controls and specifically exclude functionality and data structures internal to the operation of the controls.

## What to Check

- [ ] Verify SA-4(1) Functional Properties of Controls is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for SA-4(1)
- [ ] 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(1) 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 the developer of the system, system component, or system service to provide a description of the functional properties of the controls to be implemented.

### Implementation Guidance

Functional properties of security and privacy controls describe the functionality (i.e., security or privacy capability, functions, or mechanisms) visible at the interfaces of the controls and specifically exclude functionality and data structures internal to the operation of the controls.

## Risk Assessment

| Finding                                                   | Severity | Impact                                     |
| --------------------------------------------------------- | -------- | ------------------------------------------ |
| SA-4(1) Functional Properties of Controls not implemented | Medium   | System and Services Acquisition            |
| SA-4(1) partially implemented                             | Low      | Incomplete System and Services Acquisition |

## CWE Categories

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

## References

- [NIST SP 800-53 Rev 5 - SA-4(1)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=sa-4.1)
- [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 (none) reviewed