---
title: "NIST 800-171 3.13.15 (SC.L2-3.13.15): Session Authenticity"
description: "NIST SP 800-171 3.13.15 Session Authenticity: 5 SPRS points, not allowed on a CMMC POA&M. The text, what assessors check and the evidence."
url: https://policycortex.com/nist-800-171/system-and-communications-protection/3.13.15
sealed: 2026-11-11
amended: 2026-11-11
register: nist-800-171/system-and-communications-protection/3.13.15
records: 7
digest: sha3:dae3ed609c0133d9c18674a431577ba059a11a3fab58580f45a0ca68bf529d31
---

# NIST 800-171 3.13.15 (SC.L2-3.13.15): Session Authenticity

NIST 800-171 / System and Communications Protection / 3.13.15

"Protect the authenticity of communications sessions." ([NIST SP 800-171 Rev. 2, requirement 3.13.15](https://doi.org/10.6028/NIST.SP.800-171r2))

CMMC Level 2 practice SC.L2-3.13.15.

## What 3.13.15 means in practice

Communications sessions are protected against hijacking and man-in-the-middle attacks, so each side knows it is still talking to the right party. TLS with valid certificates, signed tokens and secure session handling in applications are the common protections.

## SPRS points and the CMMC POA&M

- **CMMC Level 2 practice**: SC.L2-3.13.15
- **SPRS points**: 5 points. When it is not met, the DoD Assessment Methodology subtracts 5 from the score of 110.
- **CMMC POA&M**: Not allowed. It is worth 5 points, and 32 CFR 170.21(a)(2)(ii) admits only requirements worth 1 point, with one exception: 3.13.11 when encryption is used but not FIPS validated.

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 3.13.15

NIST SP 800-171A gives one determination statement for 3.13.15.

- Determine if the authenticity of communications sessions is protected.

[NIST SP 800-171A (June 2018), assessment objectives for 3.13.15](https://doi.org/10.6028/NIST.SP.800-171A)

## Evidence that shows 3.13.15 is met

- TLS configuration and certificates for applications and services.
- Application session management settings, such as secure, short-lived session tokens.
- Results of a web application scan or test that covered session handling.

## How PolicyCortex gathers the evidence

PolicyCortex reads this evidence with the collectors below, read only, and grades 3.13.15 from it. Each line says what the product checks.

- **Azure App Service: App settings.** Checks that App Service communications sessions are protected with TLS.

## Related pages

- **Calculator**: [SPRS score calculator: mark 3.13.15 and the other 109 requirements and see the score.](https://policycortex.com/sprs-score-calculator#family-SC)
- **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 16 System and Communications Protection requirements (3.13).](https://policycortex.com/nist-800-171/system-and-communications-protection)
- **Previous**: [3.13.14: Voice over IP](https://policycortex.com/nist-800-171/system-and-communications-protection/3.13.14)
- **Next**: [3.13.16: CUI at Rest](https://policycortex.com/nist-800-171/system-and-communications-protection/3.13.16)
- **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 | fddc26ffeb44 | e4d6a5911c58 |
| REC 0001 | MEANING | 3dc7d4b29813 | fddc26ffeb44 |
| REC 0002 | POINTS AND POA&M | b4dff12f1c56 | 3dc7d4b29813 |
| REC 0003 | ASSESSMENT OBJECTIVES | 26f72b43a5c6 | b4dff12f1c56 |
| REC 0004 | EVIDENCE | d544a9cd0de0 | 26f72b43a5c6 |
| REC 0005 | COLLECTORS | dce7bc6b467a | d544a9cd0de0 |
| REC 0006 | RELATED | dae3ed609c01 | dce7bc6b467a |

Head sha3:dae3ed609c0133d9c18674a431577ba059a11a3fab58580f45a0ca68bf529d31. 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.