---
title: "NIST 800-171 3.1.18 (AC.L2-3.1.18): Mobile Device Connection"
description: "NIST SP 800-171 3.1.18 Mobile Device Connection: 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/access-control/3.1.18
sealed: 2026-11-11
amended: 2026-11-11
register: nist-800-171/access-control/3.1.18
records: 7
digest: sha3:8c2f98ee44f875e974b0c442efee7d21ba8b97c7f2976815024af972ee60f2ae
---

# NIST 800-171 3.1.18 (AC.L2-3.1.18): Mobile Device Connection

NIST 800-171 / Access Control / 3.1.18

"Control connection of mobile devices." ([NIST SP 800-171 Rev. 2, requirement 3.1.18](https://doi.org/10.6028/NIST.SP.800-171r2))

CMMC Level 2 practice AC.L2-3.1.18.

## What 3.1.18 means in practice

Phones and tablets that touch CUI are known and may connect only under your rules. In practice that means enrollment in device management, a compliance policy (passcode, current software, no jailbreak) and sign-in rules that admit only compliant or approved devices, with their connections logged.

## SPRS points and the CMMC POA&M

- **CMMC Level 2 practice**: AC.L2-3.1.18
- **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.
- **Scoring note**: If no mobile device may connect, mark Met: Annex A subtracts nothing. Keep a policy and procedure that stops it being turned on by accident: without one, a Medium assessment takes 1 point.

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 3.1.18

NIST SP 800-171A gives 3 determination statements for 3.1.18, each found satisfied or other than satisfied. Determine if:

- 3.1.18[a] mobile devices that process, store, or transmit CUI are identified.
- 3.1.18[b] mobile device connections are authorized.
- 3.1.18[c] mobile device connections are monitored and logged.

[NIST SP 800-171A (June 2018), assessment objectives for 3.1.18](https://doi.org/10.6028/NIST.SP.800-171A)

## Evidence that shows 3.1.18 is met

- An inventory of the mobile devices that process, store or transmit CUI.
- Mobile device management compliance policies.
- Sign-in rules that require a compliant device or an approved app.
- Logs of mobile device connections.

## How PolicyCortex gathers the evidence

PolicyCortex reads this evidence with the collectors below, read only, and grades 3.1.18 from it. Each line says what the product checks.

- **Microsoft Intune: Compliance policies · Device configurations.** Checks that the compliance policies reaching every iOS and Android device Intune manages require authentication and block jailbroken or rooted devices.
- **Microsoft Entra ID: Conditional Access.** Checks that Conditional Access requires a compliant device, an approved app or an app protection policy for iOS and Android sign-ins, or blocks them.

## Related pages

- **Calculator**: [SPRS score calculator: mark 3.1.18 and the other 109 requirements and see the score.](https://policycortex.com/sprs-score-calculator#family-AC)
- **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 22 Access Control requirements (3.1).](https://policycortex.com/nist-800-171/access-control)
- **Previous**: [3.1.17: Wireless Protection](https://policycortex.com/nist-800-171/access-control/3.1.17)
- **Next**: [3.1.19: Encrypt CUI on Mobile](https://policycortex.com/nist-800-171/access-control/3.1.19)
- **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 | c6ee7a28af86 | 5fea0ad44f65 |
| REC 0001 | MEANING | 21be9aaa70f4 | c6ee7a28af86 |
| REC 0002 | POINTS AND POA&M | da64815bf59c | 21be9aaa70f4 |
| REC 0003 | ASSESSMENT OBJECTIVES | 0f7ad84627f5 | da64815bf59c |
| REC 0004 | EVIDENCE | 9909aec2484a | 0f7ad84627f5 |
| REC 0005 | COLLECTORS | 8ec7a5131cc1 | 9909aec2484a |
| REC 0006 | RELATED | 8c2f98ee44f8 | 8ec7a5131cc1 |

Head sha3:8c2f98ee44f875e974b0c442efee7d21ba8b97c7f2976815024af972ee60f2ae. 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.