What evidence do auditors commonly ask for on 22 Network segmentation (Excellent)?

Segmentation rule review records showing each inter-zone allow rule re-approved or removed at the last review; Network segmentation design showing zones, trust boundaries and the systems placed in each; Firewall and ACL rule sets between segments with a default-deny stance and business justification for each allow rule; Results of segmentation testing confirming workstations cannot reach each other or restricted zones.

What is the most common gap auditors find on 22?

Flat network where workstations can freely connect to one another over SMB and RDP

ASD Strategies to Mitigate Cyber Security Incidents · Limiting the Extent of Cyber Security Incidents

`22` Network segmentation (Excellent)

Network segmentation and segregation to limit the impact of an intrusion. Deny traffic between computers unless required.

Source: ASD Strategies to Mitigate Cyber Security Incidents, 22. 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 ASD Strategies to Mitigate Cyber Security Incidents in the compliance library.

artefacts

held by a system

at each review

moderate

to go live

Cloud console / configuration management

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 and ACL rule sets between segments with a default-deny stance and business justification for each allow rule · Cloud console / configuration management

periodic reviewEvidence produced at each review

Segmentation rule review records showing each inter-zone allow rule re-approved or removed at the last review · Cloud console / configuration management
Results of segmentation testing confirming workstations cannot reach each other or restricted zones · Endpoint management (MDM / EDR)

governing documentDocuments that govern the control

Network segmentation design showing zones, trust boundaries and the systems placed in each · Policy repository / GRC workspace

First move

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

Common gaps auditors find

Flat network where workstations can freely connect to one another over SMB and RDP
Inter-segment firewall rules left as any-any for convenience during a past project
Rules approved once and never reviewed, leaving stale allow rules for decommissioned systems

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

21 Disable local administrator accounts (Excellent) · 23 Protect authentication credentials (Excellent)