---
title: "NIST 800-171 3.12.4 (CA.L2-3.12.4): System Security Plan"
description: "NIST SP 800-171 3.12.4 System Security Plan: no SPRS point value, never on a CMMC POA&M. The text, what assessors check and the evidence."
url: https://policycortex.com/nist-800-171/security-assessment/3.12.4
sealed: 2026-11-11
amended: 2026-11-11
register: nist-800-171/security-assessment/3.12.4
records: 7
digest: sha3:be70586a9e139ff3e1ceeb0223ee507c43551015633dcaf348a83b4f617f84a0
---

# NIST 800-171 3.12.4 (CA.L2-3.12.4): System Security Plan

NIST 800-171 / Security Assessment / 3.12.4

"Develop, document, and periodically update system security plans that describe system boundaries, system environments of operation, how security requirements are implemented, and the relationships with or connections to other systems." ([NIST SP 800-171 Rev. 2, requirement 3.12.4](https://doi.org/10.6028/NIST.SP.800-171r2))

CMMC Level 2 practice CA.L2-3.12.4.

## What 3.12.4 means in practice

The system security plan describes the system: its boundary, its environment of operation, how each requirement is implemented, and how it connects to other systems. It is updated on a set schedule and when the system changes. Without one an assessment cannot be completed, so no SPRS score is produced.

## SPRS points and the CMMC POA&M

- **CMMC Level 2 practice**: CA.L2-3.12.4
- **SPRS points**: No point value of its own.
- **CMMC POA&M**: Never. 32 CFR 170.21(a)(2)(iii) names 3.12.4 among the 6 requirements a CMMC POA&M may never include, whatever their point value.
- **Scoring note**: No point value. Without a system security plan an assessment cannot be completed, so no score is produced.

Sources: [NIST SP 800-171 DoD Assessment Methodology, version 1.2.1 (June 24, 2020), Annex A](https://www.acq.osd.mil/asda/dpc/cp/cyber/docs/safeguarding/NIST-SP-800-171-Assessment-Methodology-Version-1.2.1-6.24.2020.pdf); [32 CFR 170.21, Plan of Action and Milestones requirements](https://www.ecfr.gov/current/title-32/section-170.21).

## What an assessor checks for 3.12.4

NIST SP 800-171A gives 8 determination statements for 3.12.4, each found satisfied or other than satisfied. Determine if:

- 3.12.4[a] a system security plan is developed.
- 3.12.4[b] the system boundary is described and documented in the system security plan.
- 3.12.4[c] the system environment of operation is described and documented in the system security plan.
- 3.12.4[d] the security requirements identified and approved by the designated authority as non-applicable are identified.
- 3.12.4[e] the method of security requirement implementation is described and documented in the system security plan.
- 3.12.4[f] the relationship with or connection to other systems is described and documented in the system security plan.
- 3.12.4[g] the frequency to update the system security plan is defined.
- 3.12.4[h] system security plan is updated with the defined frequency.

[NIST SP 800-171A (June 2018), assessment objectives for 3.12.4](https://doi.org/10.6028/NIST.SP.800-171A)

## Evidence that shows 3.12.4 is met

- The current system security plan, with its approval and date.
- The boundary diagram and the list of connections to other systems in the plan.
- An implementation description for each requirement.
- The update schedule and the revision history.

## How PolicyCortex gathers the evidence

No PolicyCortex collector reads the evidence for 3.12.4. Your team provides the evidence listed above.

## Related pages

- **Calculator**: [SPRS score calculator: mark 3.12.4 and the other 109 requirements and see the score.](https://policycortex.com/sprs-score-calculator#family-CA)
- **Sample package**: [Sample package: an SSP, a POA&M and an evidence chain the product generated from demonstration data.](https://policycortex.com/sample-package)
- **Family**: [All 4 Security Assessment requirements (3.12).](https://policycortex.com/nist-800-171/security-assessment)
- **Previous**: [3.12.3: Ongoing Monitoring](https://policycortex.com/nist-800-171/security-assessment/3.12.3)
- **Next**: [3.13.1: Boundary Protection](https://policycortex.com/nist-800-171/system-and-communications-protection/3.13.1)
- **All requirements**: [All 110 NIST SP 800-171 requirements, by family.](https://policycortex.com/nist-800-171)

Meet the requirement once. Keep the evidence current. [Request Access](https://app.policycortex.com/auth?mode=request-access) · [Book a call](https://policycortex.com/book)

## Register colophon

| Seq | Label | SHA3-256 | Prev |
|---|---|---|---|
| REC 0000 | REQUIREMENT | b65da5a18e1e | eb20093016a6 |
| REC 0001 | MEANING | c380f88c472a | b65da5a18e1e |
| REC 0002 | POINTS AND POA&M | 45a5da18a083 | c380f88c472a |
| REC 0003 | ASSESSMENT OBJECTIVES | a300219229ff | 45a5da18a083 |
| REC 0004 | EVIDENCE | 8899e8a68220 | a300219229ff |
| REC 0005 | COLLECTORS | d7dccde1f9d1 | 8899e8a68220 |
| REC 0006 | RELATED | be70586a9e13 | d7dccde1f9d1 |

Head sha3:be70586a9e139ff3e1ceeb0223ee507c43551015633dcaf348a83b4f617f84a0. Each digest is SHA3-256 over the previous digest, the register key, the record label, and the record copy; a second party can recompute it from this document.