SA 17(1) Formal Policy Model

---
name: "SA-17(1)_formal-policy-model"
description: "Require the developer of the system, system component, or system service to: Produce, as an integral part of the development process, a formal policy "
category: "configuration"
version: "5.2.0"
author: "cyberstrike-official"
tags:
  - nist
  - sp800-53
  - rev5
  - sa-17-1
  - sa
  - enhancement
tech_stack:
  - any
cwe_ids:
  - CWE-16
chains_with:
  - AC-3
  - AC-4
  - AC-25
prerequisites:
  - SA-17
severity_boost:
  AC-3: "Chain with AC-3 for comprehensive security coverage"
  AC-4: "Chain with AC-4 for comprehensive security coverage"
  AC-25: "Chain with AC-25 for comprehensive security coverage"
---

# SA-17(1) Formal Policy Model

> **Enhancement of:** SA-17

## High-Level Description

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

Formal models describe specific behaviors or security and privacy policies using formal languages, thus enabling the correctness of those behaviors and policies to be formally proven. Not all components of systems can be modeled. Generally, formal specifications are scoped to the behaviors or policies of interest, such as nondiscretionary access control policies. Organizations choose the formal modeling language and approach based on the nature of the behaviors and policies to be described and the available tools.

## What to Check

- [ ] Verify SA-17(1) Formal Policy Model is documented in SSP
- [ ] Validate all 2 control requirements are implemented
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for SA-17(1)
- [ ] Verify enhancement builds upon base control SA-17

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SA-17(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:
Produce, as an integral part of the development process, a formal policy model describing the [organization-defined] to be enforced; and
Prove that the formal policy model is internally consistent and sufficient to enforce the defined elements of the organizational security and privacy policy when implemented.

### Implementation Guidance

Formal models describe specific behaviors or security and privacy policies using formal languages, thus enabling the correctness of those behaviors and policies to be formally proven. Not all components of systems can be modeled. Generally, formal specifications are scoped to the behaviors or policies of interest, such as nondiscretionary access control policies. Organizations choose the formal modeling language and approach based on the nature of the behaviors and policies to be described and the available tools.

## Risk Assessment

| Finding                                      | Severity | Impact                                     |
| -------------------------------------------- | -------- | ------------------------------------------ |
| SA-17(1) Formal Policy Model not implemented | Medium   | System and Services Acquisition            |
| SA-17(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-17(1)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=sa-17.1)
- [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 (AC-3, AC-4, AC-25) reviewed