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

SSP AC-4 statement describing the flow control rules between boundary zones, including security groups, proxies and data egress restrictions; Network flow diagram and firewall or security group rule export matching the approved flows; Role-based access matrix mapped to job functions and data classifications; Account provisioning and deprovisioning workflow tickets with manager approvals; Quarterly privileged access review attestations; System access request forms with business justification.

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

Privileged accounts shared across administrators without individual accountability

FedRAMP Moderate (NIST SP 800-53 Rev 5 baseline) · AC - Access Control

`AC-4` Information Flow Enforcement

Enforce approved information flow control policies between connected systems and within the system.

Source: FedRAMP Moderate (NIST SP 800-53 Rev 5 baseline), 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 FedRAMP Moderate (NIST SP 800-53 Rev 5 baseline) in the compliance library.

A FedRAMP baseline is a subset of NIST SP 800-53 Rev 5, enhancements included.

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

Network flow diagram and firewall or security group rule export matching the approved flows · Identity provider / directory
Account provisioning and deprovisioning workflow tickets with manager approvals · Identity provider / directory

periodic reviewEvidence produced at each review

Quarterly privileged access review attestations · Identity provider / directory
Joiner mover leaver workflow evidence integrated with HR · Identity provider / directory

governing documentDocuments that govern the control

SSP AC-4 statement describing the flow control rules between boundary zones, including security groups, proxies and data egress restrictions · Policy repository / GRC workspace
Role-based access matrix mapped to job functions and data classifications · Policy repository / GRC workspace
System access request forms with business justification · Policy repository / GRC workspace

First move

Start with the 2 of 7 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

Privileged accounts shared across administrators without individual accountability
Access reviews performed but exceptions never remediated
Role definitions drift from documented matrix without change control
Service accounts excluded from periodic recertification

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-4(21) Physical or Logical Separation of Information Flows