What evidence do auditors commonly ask for on AC-4 Information Flow Enforcement?

Documented flows to and from supply chain parties; Enforcement rules implementing those flows; Classification of information shared with suppliers.

What is the most common gap auditors find on AC-4?

supplier file transfer paths outside the flow model

NIST SP 800-161 Rev 1 (supply chain) · C-SCRM Family: Access Control

`AC-4` Information Flow Enforcement

Controls where supply chain information moves, including data shared with and received from suppliers and integrators.

Source: NIST SP 800-161 Rev 1 (supply chain), AC-4. 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 NIST SP 800-161 Rev 1 (supply chain) in the compliance library.

artefacts

held by a system

at each review

hard

to go live

Document repository

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

none for this control

governing documentDocuments that govern the control

Documented flows to and from supply chain parties · Document repository
Enforcement rules implementing those flows · Document repository
Classification of information shared with suppliers · Vendor register / contract repository

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

supplier file transfer paths outside the flow model
inbound supplier data trusted without inspection

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-3 Access Enforcement · AC-5 Separation of Duties