In this ultimate how to implement guide to ISO 27001 Annex A 5.26 Response to Information Security Incidents, you will learn directly from an ISO 27001 Lead Auditor:
- The requirement of the control
- The required implementation steps
- The minimum requirement
I am Stuart Barker, the ISO 27001 Lead Auditor and author of the Ultimate ISO 27001 Toolkit.
Using over 30 years of industry experience across hundreds of audits, I’m giving you the exact templates, walkthroughs, and practical examples you need to achieve ISO 27001 certification.
Table of contents
- ISO 27001 Annex A Response to Information Security Incidents Implementation Checklist
- 1. Formal Activation of the Incident Response Team (IRT)
- 2. Immediate Containment and Isolation
- 3. Preservation of Volatile Evidence
- 4. Manual Root Cause Triage
- 5. Strategic Eradication of the Threat
- 6. Secure Restoration from Trusted Backups
- 7. Execution of Internal Communications
- 8. Regulatory and External Notification
- 9. Post-Response Integrity Verification
- 10. Formal Incident Closure and Handover
- ISO 27001 Annex A 5.26 SaaS / GRC Platform Implementation Failure Checklist
Implementing ISO 27001 Annex A 5.26 is the essential process of establishing a robust technical response to security incidents. The primary implementation requirement focuses on active containment and forensic evidence preservation, delivering the business benefit of minimized operational downtime and full compliance with international data protection standards.
ISO 27001 Annex A Response to Information Security Incidents Implementation Checklist
Use this implementation checklist to achieve compliance with ISO 27001 Annex A 5.26. Successful certification requires evidence of active, manual intervention during security events rather than passive reliance on automated software notifications.
1. Formal Activation of the Incident Response Team (IRT)
Control Requirement: A designated team must be formally mobilised following the assessment of a security event as an incident.
Required Implementation Step: Open your Incident Management Procedure and trigger the call-out list via telephone or secure out-of-band messaging. Do not rely on a GRC dashboard; you must physically or digitally verify that each member has acknowledged their specific role in the response.
Minimum Requirement: Provide a dated call-log or timestamped message thread showing the IRT Lead officially declaring the incident and assigning roles.
2. Immediate Containment and Isolation
Control Requirement: Actions must be taken to limit the spread and impact of the incident.
Required Implementation Step: Execute physical or logical isolation of the affected assets. This involves logging into the firewall or hypervisor to shut down ports or isolate VLANs, ensuring the threat cannot traverse the network while you investigate.
Minimum Requirement: Evidence of a specific configuration change (e.g., a firewall rule update) timestamped within the incident window.
3. Preservation of Volatile Evidence
Control Requirement: Evidence must be collected and protected before it is lost or tampered with during the response.
Required Implementation Step: Create a bit-for-bit image of affected memory (RAM) or disk partitions before rebooting or patching. Document the chain of custody manually, including the name of the person who performed the dump and the hash of the resulting file.
Minimum Requirement: A signed evidence log containing the SHA-256 hash of the forensic image captured during the triage.
