ISO27001:2022 – A5.27 Learning from information security incidents

Introduction to ISO 27001 – A5.27

ISO 27001 – A5.27 is part of a series focused on incident management. Be sure to also review:

• A5.24 – Information security incident management planning and preparation
• A5.25 – Assessment and decision on information security events
• A5.26 – Response to information security incidents
• A5.28 – Collection of evidence
• A5.29 – Information security during disruption
• A5.30 – ICT Readiness for Business Continuity

What does ISO 27001 – A5.27 require?

“Knowledge gained from information security incidents shall be used to strengthen and improve the information security controls.”

(ISO 27001 – A5.27 – Learning from Information Security Incidents)

Why is ISO 27001 – A5.27 required?

Security incidents provide an opportunity to learn and improve. By reflecting on what happened and how it was handled, organisations can identify vulnerabilities, enhance controls, and reduce the likelihood of recurrence.

What the auditor is looking for in relation to ISO 27001 – A5.27

The auditor will look for:

• Post Incident Review (PIR) reports
• Root Cause Analysis (RCA) documentation
• Corrective action logs
• Meeting minutes or change records
• Evidence of updated policies, procedures, or risk registers

What do you need to do?

Focus on two elements post-incident:

1. Post Incident Review (PIR)

• Create a timeline of the incident response
• Identify who was notified and how escalation occurred
• Document what went well and what could be improved
• Capture lessons learned and actions in a simple Word document

2. Root Cause Analysis (RCA)

Focus on why the incident happened, not who was responsible. Ask:

• Was the process followed?
• Were staff trained properly?
• Were there environmental or external factors?

Use methods like the 5 Whys or a fishbone diagram to get to the root cause.

Document findings and update your action log and risk register as appropriate.

Q & A

How can we conduct an effective RCA?

Gather all relevant stakeholders and clearly explain that the session is not about assigning blame. Focus on facts, causes, and improvements. Be prepared to navigate emotions and ensure it is a safe, respectful discussion.

Do we need to do a PIR and RCA for every incident?

No. Minor incidents, like a lost laptop, might not require a formal RCA. However, always capture lessons learned in your incident log and document any follow-up actions.

Difficulty Rating

3 out of 5 – No technical skills required, but this control demands strong communication, emotional intelligence, and facilitation skills. People may prefer to move on, but it’s essential to take time to reflect, learn, and strengthen future responses.

More Questions?

ISO27001 is an interconnected standard. Use our guide and FAQs to explore related controls. If you need assistance or templates, please get in touch.

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