In the world of information security, not every digital “ping” or system anomaly is a catastrophe. However, the ability to quickly distinguish a routine event from a full-blown crisis is what separates resilient organisations from those that end up in the headlines. This is exactly what Annex A 5.25: Assessment and Decision on Information Security Events is all about.
If you are transitioning your Information Security Management System (ISMS) from the 2013 standard to the 2022 update, you might be looking for “the old version” of this control. While the logic existed in the previous version, the 2022 update has brought significant structural and qualitative changes. Let’s break down exactly what has shifted.
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The Structural Shift: From Domain 16 to Theme 5
In the ISO 27001:2013 framework, the management of security events was part of a broader, somewhat fragmented domain: Domain A.16 (Information Security Incident Management). Specifically, the concepts now found in 5.25 were primarily touched upon in A.16.1.4 (Assessment of and decision on information security events).
In the 2022 version, this has been refined and placed under the “Organisational Controls” theme as Annex A 5.25. This change signifies that assessing events isn’t just a technical IT task, it’s a fundamental organisational process. By isolating this as its own control, the standard puts a spotlight on the decision-making phase of the incident lifecycle.
Defining the “Event” vs. “Incident” Gap
One of the most important aspects of Annex A 5.25 is the formalised distinction between an event and an incident. While this distinction existed in the 2013 guidance, the 2022 update is much more prescriptive about how you bridge that gap.
An event is essentially any observable occurrence in a system (like a failed login attempt or a firewall alert). An incident is an event that actually threatens or compromises your information security. According to Hightable.io, the new standard requires a much more robust “triage” system. You must prove that you have clear, documented criteria for deciding when an event needs to be escalated into an incident response workflow.
What is New in the 2022 Requirements?
While the goal remains the same, filtering the noise to find the real threats, the 2022 update introduces several nuances that will impact your day-to-day operations:
- Consistent Categorisation: There is a heavier emphasis on using a standardised classification scheme. You can’t just rely on the gut feeling of a security analyst; you need a matrix that defines severity based on impact and urgency.
- Point of Contact (PoC): The 2022 standard is clearer about the need for designated individuals or roles who are authorised to make the final “call.” As noted by Hightable.io, auditors now look for a clear RACI (Responsible, Accountable, Consulted, Informed) chart specifically for the assessment phase.
- Record-Keeping for “Non-Incidents”: A subtle but vital change is the expectation that you document the decisions for events that weren’t escalated. If you decide a suspicious alert is a false positive, you now need to be able to show your reasoning to an auditor.
The Rise of Automated Assessment
The 2013 version of the standard was written in a world where manual log review was still common. The 2022 version, and specifically the implementation guidance for 5.25, acknowledges the role of modern technology.
It encourages the use of automated tools (like SIEMs or SOAR platforms) to assist in the initial assessment. However, the standard is careful to note that the decision, the human-led or policy-led choice to escalate, must still follow your organisational rules. Hightable.io suggests that if you are using automation, your “playbooks” must be explicitly mapped to your Annex A 5.25 criteria to ensure compliance.
Practical Impact: Updating Your Playbooks
For those moving to the 2022 version, your main task for Annex A 5.25 is to update your Incident Management Procedure. You should look to separate the “Reporting” (5.24) from the “Assessment” (5.25).
Key areas to document include:
- The specific criteria used to determine if an event is an incident (e.g., “any event impacting more than 50 users” or “any detected malware on a production server”).
- The priority levels (Low, Medium, High, Critical) and the specific definitions for each.
- The timeline for assessment – how long does the team have to make a decision once an event is detected?
Why This Change Strengthens Your ISMS
Ultimately, the transition to ISO 27001:2022 Annex A 5.25 is about reducing “alert fatigue.” By forcing organisations to formalise their assessment and decision processes, the standard helps teams focus on the threats that actually matter. It moves security from a “reactive” state of constant firefighting to a “disciplined” state of triage and response.
If you’re finding the mapping between the 2013 and 2022 versions a bit complex, using the structured assessment templates and incident trackers from Hightable.io can help you build a decision-making framework that satisfies auditors and protects your data.