What evidence do auditors commonly ask for on AC.L2-3.1.21 Portable Storage Use?

Policy stating limits on portable storage use on external systems; Technical restriction or endpoint control evidence; Records of approved exceptions.

What is the most common gap auditors find on AC.L2-3.1.21?

Policy silent on external system use specifically

CMMC 2.0 · Access Control

`AC.L2-3.1.21` Portable Storage Use

Restrict how organizational portable storage devices may be used when connected to systems outside organizational control.

Source: CMMC 2.0, AC.L2-3.1.21. The statement above is our statement of the clause, read from the published text and cited so you can check it against the official text, not the instrument verbatim. Open CMMC 2.0 in the compliance library.

artefacts

held by a system

at each review

hard

to go live

Policy repository / GRC workspace

where the evidence lives

teal = a system already holds it · olive = produced at each review. To go live: easy when half or more of the artefacts are already held by a system, moderate from a quarter to a half, hard below a quarter.

These are the artefacts auditors commonly ask for on this requirement, our guidance rather than text from the standard. Your assessor decides what is sufficient in your context, and asks for samples across the period when a report covers one.

system holds itEvidence a system already holds

none for this control

periodic reviewEvidence produced at each review

Technical restriction or endpoint control evidence · Endpoint management (MDM / EDR)
Records of approved exceptions · Identity provider / directory

governing documentDocuments that govern the control

Policy stating limits on portable storage use on external systems · Policy repository / GRC workspace

First move

No system holds this evidence for you: it is people and documents. Reminders and routing to the owner still save time. Put the document under version control with an owner and review date, and log each review as a record with reviewer and date.

Common gaps auditors find

Policy silent on external system use specifically
Restriction applied internally but not to devices taken off site
No mechanism to detect violation

Do this for your whole sheet

Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.

Build my evidence sheet

AC.L2-3.1.20 External Connections · AC.L2-3.1.22 Control Public Information