What evidence do auditors commonly ask for on AC-4(2) Information Flow Enforcement | Processing Domains?

Access control policy; Information flow control policies; Procedures addressing information flow enforcement; System design documentation; System security architecture and associated documentation; System configuration settings and associated documentation.

What is the most common gap auditors find on AC-4(2)?

Information flow control is enforced without protected processing domains, so policy can be bypassed within a shared domain

NIST SP 800-53 Rev 5 · AC - Access Control

`AC-4(2)` Information Flow Enforcement | Processing Domains

Use protected processing domains to enforce organization-defined information flow control policies as a basis for flow control decisions.

Source: NIST SP 800-53 Rev 5, AC-4(2). 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 800-53 Rev 5 in the compliance library.

Base controls and their enhancements. Which apply follows the baseline you are assessed against (for example FedRAMP Moderate or High, or the low, moderate and high baselines of SP 800-53B). Text in square brackets is a parameter your organisation sets.

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

Test of Mechanisms implementing information flow enforcement policy · Identity provider / directory

periodic reviewEvidence produced at each review

System audit records · Identity provider / directory

governing documentDocuments that govern the control

Access control policy · Policy repository / GRC workspace
Information flow control policies · Policy repository / GRC workspace
Procedures addressing information flow enforcement · Policy repository / GRC workspace
System design documentation · Policy repository / GRC workspace
System security architecture and associated documentation · Policy repository / GRC workspace
System configuration settings and associated documentation · Policy repository / GRC workspace
System security plan · Policy repository / GRC workspace

First move

Mostly documents and reviews. Pull the 1 system-held artefact from your Identity provider / directory on a schedule; put the documents under version control with an owner and review date, and log each review as a dated record with a named reviewer.

Common gaps auditors find

Information flow control is enforced without protected processing domains, so policy can be bypassed within a shared domain
No documentation shows which processing domains enforce the defined flow control policies

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-4(1) Information Flow Enforcement | Object Security and Privacy Attributes · AC-4(3) Information Flow Enforcement | Dynamic Information Flow Control