What evidence do auditors commonly ask for on A.8.20 Networks security?

Statement of Applicability entry for control A.8.20, showing inclusion or justified exclusion, implementation status and the risks it treats; Current network diagrams and device configuration backups for routers, switches, firewalls and wireless controllers; Defined responsibilities and procedures for network device management, separated from system operations where appropriate; Firewall rule sets, network access control configuration and device authentication (for example 802.1X) restricting what can connect; Hardening standards for network devices and evidence that insecure protocols are disabled.

What is the most common gap auditors find on A.8.20?

Network diagrams are years out of date

ISO/IEC 27001:2022 · Technological controls

`A.8.20` Networks security

Networks and network devices are to be secured, managed and controlled so that information in systems and applications is protected. Purpose (stated in ISO/IEC 27002:2022): protects information in networks and supporting facilities from compromise via the network. As an Annex A reference control, it is compared with the controls determined in risk treatment (6.1.3 c) and recorded in the Statement of Applicability as included or excluded, with the justification and implementation status (6.1.3 d); implementation guidance is ISO/IEC 27002:2022 8.20.

Source: ISO/IEC 27001:2022, A.8.20. 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 ISO/IEC 27001:2022 in the compliance library.

Clauses 4 to 10 are the management-system requirements: none of them can be excluded when an organisation claims conformity. The 93 Annex A controls are a reference set: one may be excluded with a justification in the Statement of Applicability. Certification bodies assess conformity; the evidence lists here are what auditors commonly ask for, not a list the standard prescribes.

artefacts

held by a system

at each review

moderate

to go live

Backup / DR tooling

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

Current network diagrams and device configuration backups for routers, switches, firewalls and wireless controllers · Backup / DR tooling
Firewall rule sets, network access control configuration and device authentication (for example 802.1X) restricting what can connect · Endpoint management (MDM / EDR)

periodic reviewEvidence produced at each review

none for this control

governing documentDocuments that govern the control

Statement of Applicability entry for control A.8.20, showing inclusion or justified exclusion, implementation status and the risks it treats · Policy repository / GRC workspace
Defined responsibilities and procedures for network device management, separated from system operations where appropriate · Policy repository / GRC workspace
Hardening standards for network devices and evidence that insecure protocols are disabled · Policy repository / GRC workspace

First move

Start with the 2 of 5 artefacts that already live in a system (Backup / DR tooling); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

Network diagrams are years out of date
Management interfaces of network devices are reachable from user networks
Unknown devices can connect to wired ports without any authentication
Legacy protocols such as Telnet or SNMPv1 remain enabled

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

A.8.19 Installation of software on operational systems · A.8.21 Security of network services