Level 2 · Access Control
AC.L2-3.1.21
Portable Storage Use
Portable storage restrictions need to address use on external systems, not just use inside the organization.
Official reference
The requirement
Limit use of portable storage devices on external systems.
DoD CMMC Assessment Guide, Level 2, version 2.13. AC.L2-3.1.21; requirement and objectives, printed page 61 ↗
Assessment objectives
What must be established
Determine if each applicable objective is satisfied. The labels below follow the cited DoD assessment guide.
- [a]
the use of portable storage devices containing CUI on external systems is identified and documented;
- [b]
limits on the use of portable storage devices containing CUI on external systems are defined; and
- [c]
the use of portable storage devices containing CUI on external systems is limited as defined.
MET requires evidence that all applicable objectives are satisfied. Final, approved evidence is needed. A NOT APPLICABLE determination needs a scope-based basis and is equivalent to MET for scoring. Enduring exceptions and temporary deficiencies have specific conditions under 32 CFR 170.24; they are not a general permission to defer implementation.
GAVII Cybersecurity assessment approach
Connect the objective to the evidence
Identify the portable media that staff may take to customer, supplier, or personal systems. The evidence should explain how the permitted use is limited and communicated.
Assessment focus: objectives [a], [b], [c]. Use the methods together; a single example does not establish every objective.
Examine
Review portable-storage policies, authorized external uses, device restrictions, and relevant custody records.
Interview
Which external systems may receive organizational portable media, and what prevents broader use?
Demonstrate or test
Show the process and technical restrictions for an approved transfer using nonsensitive test media.
Evidence gaps to look for
- USB controls cover office endpoints but no one defines use on external systems.
- Staff treat encrypted media as unrestricted media.
GAVII Cybersecurity’s examples illustrate ways to examine, interview, and test. They are not a mandatory artifact list or a guarantee of an assessment result. Combine methods and address every applicable objective in the actual scope.
Assessment constraints
Scoring and POA&M eligibility
Score: 1
If this requirement is NOT MET, deduct 1 point from the Level 2 maximum of 110. The deduction applies to the requirement, not separately to each objective.
Scoring rule ↗POA&M: Eligible
Potentially eligible only if all Conditional Level 2 criteria are satisfied, including a score of at least 88 out of 110 and timely closeout. Eligibility is not a finding that this requirement is MET.
POA&M rule ↗Conditional Level 2 requires a score of at least 88 out of 110 and satisfaction of every eligibility condition. A 1-point requirement is not automatically eligible. The permitted POA&M must be closed through the appropriate closeout assessment within 180 days of the Conditional CMMC Status Date. An operational remediation plan does not confer Conditional Status.
Assessment planning
Location and observation
Not specifically listed in CAP P.11
This requirement is not specifically listed in CAP P.11. That does not establish that remote assessment is sufficient: the Lead CCA and C3PAO determine an adequate approach for the actual scope and evidence.
CAP §P.11, pages 10–11 ↗Check the source
References and related requirements
- DoD CMMC Assessment Guide, Level 2 ↗AC.L2-3.1.21; requirement and objectives, printed page 61. 2.13, September 2024.
- 32 CFR 170.24: Assessment findings and scoring ↗170.24(b) and (c)(2). Current electronic Code of Federal Regulations.
- 32 CFR 170.21: POA&M eligibility and closeout ↗170.21(a)(2) and (b). Current electronic Code of Federal Regulations.
- NIST SP 800-171 Rev. 2 ↗Requirement 3.1.21. February 2020, updated January 2021.
- NIST SP 800-171A ↗Assessment procedure 3.1.21. June 2018.
- Cyber AB CMMC Assessment Process (CAP) ↗P.11, printed pages 10-11; Level 2 certification assessment-location planning. 2.0, December 2024.
Program timing and contract applicability can change independently of these requirements. Check current DoD program notices and your solicitation or contract before making a compliance decision. Open the official DoD resource hub.