ISO 27001A.5 — Learning from information security incidents
A.5.27
Learning from information security incidents
ISO 27001 · ISO/IEC 27001:2022 · Last verified July 2026
Objective
Learn from information security incidents to reduce the likelihood or impact of future events.
Points of focus
- Post-incident review process
- Root cause and contributing factors
- Corrective actions with owners/dates
- Sharing lessons appropriately
Implementation notes
Require PIR for incidents above a severity threshold within a set number of days. Capture detection gaps (feed A.8.16), access issues (A.5.15/A.8.2), and supplier failures (A.5.22). Track actions in the same system as engineering work. Summarize themes in management review and internal audit follow-up.
Audit tip: Show one incident PIR and evidence that at least one corrective action shipped.
Evidence auditors typically request:
- Postmortem or PIR templates
- Completed reviews with action items
- Tickets proving actions closed
- Management review inputs summarizing lessons
Common gaps
- Blameless postmortems that never assign work
- Repeat incidents with identical causes
- Lessons not fed into risk register
Cross-Framework Mapping
| Framework | Requirement | Implementation note |
|---|---|---|
| ISO 27001 | A.5.27 | This control |
| SOC 2 | CC7.4, CC7.5 | Related Trust Services Criteria themes — map in your crosswalk; not identical requirements. |
Primary sources
- ISO/IEC 27001:2022 Annex A: ISO/IEC 27001:2022 Annex A (A.5.27)
Frequently Asked Questions
No. Define severity triggers so learning effort matches impact.
No for 27001. Internal learning records are the requirement; external comms are a separate choice.
A.5.26 is response; A.5.27 is the improvement loop afterward.