What evidence do auditors commonly ask for on AC.L2-3.1.3 Control CUI Flow?

Documented CUI flow authorizations and approved flow paths; Firewall, proxy, DLP or gateway rules enforcing those flows; Data flow diagrams identifying CUI sources, stores and destinations; Records of blocked or exception-approved transfers.

What is the most common gap auditors find on AC.L2-3.1.3?

CUI flows documented but not technically enforced

CMMC 2.0 · Access Control

`AC.L2-3.1.3` Control CUI Flow

Enforce approved authorization rules on the movement of CUI between systems, components and destinations, so CUI flows only where policy permits.

Source: CMMC 2.0, AC.L2-3.1.3. 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

moderate

to go live

Identity provider / directory

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

Firewall, proxy, DLP or gateway rules enforcing those flows · Identity provider / directory

periodic reviewEvidence produced at each review

Records of blocked or exception-approved transfers · Identity provider / directory

governing documentDocuments that govern the control

Documented CUI flow authorizations and approved flow paths · Policy repository / GRC workspace
Data flow diagrams identifying CUI sources, stores and destinations · Policy repository / GRC workspace

First move

Start with the 1 of 4 artefacts that already live in a system (Identity provider / directory); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

CUI flows documented but not technically enforced
Egress to cloud and email paths unmonitored for CUI
No defined authorization for flows to external partners

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.L2-3.1.2 Transaction & Function Control · AC.L2-3.1.4 Separation of Duties