A.5.27 A.5 · Organisational Controls

A.5.27 — Learning from information security incidents

Use knowledge gained from IS incidents to improve controls and reduce the likelihood or impact of future incidents.

Also written as A5.27, Annex A 5.27, ISO 27001:2022 A.5.27, ISO27001 A.5.27.

Written by Jett N. · Last reviewed

What ISO 27001 A.5.27 requires

Learning from information security incidents is one of 37 Organisational Controls in ISO/IEC 27001:2022 Annex A. Use knowledge gained from IS incidents to improve controls and reduce the likelihood or impact of future incidents. Organisational controls are judged on governance rather than tooling: an auditor wants a named owner, an approval trail, and evidence the control is exercised on a defined cadence rather than written once and filed.

Audit evidence assessors look for

When preparing your Statement of Applicability (SoA) for A.5.27, gather artefacts such as:

  • Post-incident review (PIR) or lessons-learned reports
  • Evidence of control updates made following incidents
  • Incident trend analysis and metrics
  • ISMS improvement log entries linked to incidents

How A.5.27 maps to SOC 2 and NIST CSF

If you run more than one framework, the same evidence usually satisfies all of them. A.5.27 aligns with:

SOC 2: CC4.2 Evaluating and communicating deficiencies, CC7.5 Incident recovery

NIST CSF 2.0: ID.IM-01 Improvements from evaluations, ID.IM-03 Improvements from operations

ISO 27001:2013 mapping

A.5.27 consolidates the following ISO 27001:2013 control(s): A.16.1.6. If you are transitioning an existing ISMS, map your prior evidence for these to A.5.27 in your updated SoA.

Map A.5.27 to NIST CSF & SOC 2 →
Crosswalk this control in the Control Mapper & Gap Assessment.
Document the risk →
Record treatment for gaps against A.5.27 in the Risk Register.

Related Annex A controls

A.5.35 Independent review of information security A.5.26 Response to information security incidents A.5.29 Information security during disruption A.5.36 Compliance with policies, rules and standards for information security

See all 37 Organisational Controls →

Frequently asked questions

Is ISO 27001 A.5.27 mandatory?

Annex A controls are not mandatory in the abstract. Clause 6.1.3 requires you to compare your risk treatment plan against Annex A and justify, in the Statement of Applicability, any control you exclude. If your risk assessment surfaces a risk that A.5.27 addresses, excluding it needs a documented, risk-based rationale that an auditor will test.

How do auditors test ISO 27001 A.5.27?

In two passes. First design: does a documented control exist, is it owned, and does it address the risk? Then operating effectiveness: the auditor samples records from across the audit period to confirm the control actually ran. A Stage 2 audit will typically pull several samples, so evidence that only exists for the month before the audit is a common finding.

How often should A.5.27 be reviewed?

ISO 27001 sets no fixed interval — it requires review at "planned intervals" and after significant change. Annual review is the norm most certification bodies expect, with an out-of-cycle review triggered by incidents, major system changes, restructures, or new regulatory obligations. Record the review date and outcome either way; an undated control is treated as unreviewed.

What does ISO 27001 A.5.27 map to in SOC 2 and NIST CSF?

A.5.27 aligns with SOC 2 CC4.2, CC7.5 and NIST CSF ID.IM-01, ID.IM-03. Evidence gathered for one framework will usually satisfy the others, which is the basis for a test-once, satisfy-many control library.

What was A.5.27 in ISO 27001:2013?

A.5.27 consolidates 1 control(s) from the 2013 edition: A.16.1.6. When transitioning, re-point the existing evidence rather than rebuilding it — the underlying requirement has not changed materially.