What evidence do auditors commonly ask for on I&S-03 Network Security?

Network security group, firewall and service mesh rule exports; Rule justification register listing each allowed service, protocol and port with an owner and business reason; Annual firewall and network configuration review record; Evidence of encryption in transit between services (mTLS, TLS configuration); Network flow monitoring or IDS coverage report.

What is the most common gap auditors find on I&S-03?

Rules with 'any' sources or ports and no recorded justification

CSA CCM v4.1 · I&S - Infrastructure Security

`I&S-03` Network Security

Monitor, encrypt and limit traffic between environments, services and applications to authenticated, authorised connections the business justifies. Review these network settings at least yearly, backed by a written justification for every allowed service, protocol and port and any compensating control.

Source: CSA CCM v4.1, I&S-03. 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 CSA CCM v4.1 in the compliance library.

Version 4.1 adds 11 controls (among them API security, log sanitisation and a service bill of materials) and renumbers several domains. CSA accepts v4.0.x during its transition; if your STAR assessment is still on v4.0.1, check the numbering against it.

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

Network security group, firewall and service mesh rule exports · Cloud console / configuration management
Network flow monitoring or IDS coverage report · SIEM / log platform

periodic reviewEvidence produced at each review

Annual firewall and network configuration review record · Cloud console / configuration management
Evidence of encryption in transit between services (mTLS, TLS configuration) · Cloud console / configuration management

governing documentDocuments that govern the control

Rule justification register listing each allowed service, protocol and port with an owner and business reason · Policy repository / GRC workspace

First move

Start with the 2 of 5 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

Rules with 'any' sources or ports and no recorded justification
East-west traffic between services left unencrypted
Annual review done for perimeter firewalls but not for cloud security groups

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

I&S-02 Capacity and Resource Planning · I&S-04 OS Hardening and Base Controls