What evidence do auditors commonly ask for on A.5.25 Assessment and decision on information security events?

Statement of Applicability entry for control A.5.25, showing inclusion or justified exclusion, implementation status and the risks it treats; The agreed incident categorization and prioritization scheme with criteria for declaring an incident and consequence levels; Triage records showing each reported event assessed against the scheme; Detailed decision records identifying who assessed the event, the categorization and the rationale; Evidence that assessors are the designated incident coordination and response personnel.

What is the most common gap auditors find on A.5.25?

No written criteria for when an event becomes an incident, so decisions are inconsistent

ISO/IEC 27001:2022 · Organizational controls

`A.5.25` Assessment and decision on information security events

Each information security event is to be assessed and a decision made on whether it counts as an information security incident. Purpose (stated in ISO/IEC 27002:2022): ensures information security events are categorized and prioritized effectively. 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 5.25.

Source: ISO/IEC 27001:2022, A.5.25. 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

hard

to go live

Document repository

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

none for this control

periodic reviewEvidence produced at each review

Triage records showing each reported event assessed against the scheme · Document repository
Detailed decision records identifying who assessed the event, the categorization and the rationale · Document repository
Evidence that assessors are the designated incident coordination and response personnel · Document repository

governing documentDocuments that govern the control

Statement of Applicability entry for control A.5.25, showing inclusion or justified exclusion, implementation status and the risks it treats · Policy repository / GRC workspace
The agreed incident categorization and prioritization scheme with criteria for declaring an incident and consequence levels · Document repository

First move

No system holds this evidence for you: it is people and documents. Reminders and routing to the owner still save time. Put the document under version control with an owner and review date, and log each review as a record with reviewer and date.

Common gaps auditors find

No written criteria for when an event becomes an incident, so decisions are inconsistent
Events closed as non-incidents without any recorded rationale
Triage is done by whoever receives the alert rather than designated personnel
Priority is set by gut feel rather than a consequence-based scheme

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.5.24 Information security incident management planning and preparation · A.5.26 Response to information security incidents