Response to Information Security Incidents
Plain English Translation
ISO 27001 Annex A.5.26 requires organizations to respond to information security incidents following formally documented procedures. When a security breach or significant event occurs, the incident response team must execute the predefined steps for containment, eradication, recovery, and communication, ensuring a swift and coordinated reaction to minimize business impact.
Technical Implementation
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Required Actions (startup)
- Define a basic Incident Response Plan detailing who to call and how to contain a compromised system.
- Use a dedicated communication channel to coordinate incident response activities.
Required Actions (scaleup)
- Develop specific technical playbooks for common scenarios like ransomware, DDoS, and phishing.
- Conduct annual tabletop exercises to train responders and refine procedures.
Required Actions (enterprise)
- Integrate SIEM and SOAR platforms to automate initial containment actions.
- Establish a Security Operations Center with structured escalation matrices and post-incident forensic capabilities.
It requires organizations to respond to actual information security incidents strictly according to their previously documented procedures and plans to ensure consistency and effectiveness.
An event is an identified occurrence of a system or network state indicating a possible breach, whereas an incident is a verified event that has a significant probability of compromising business operations and information security.
The process should include documented procedures for triage, containment, eradication, recovery, internal and external communication, and post-incident review.
Auditors look for an approved Incident Response Plan, incident logs or tickets, root cause analysis reports, and evidence of corrective actions taken after a real or simulated incident. WatchDog Security's Compliance Center can help map these evidence items to A.5.26 and keep a clear trail of approvals, uploads, and review status for audit preparation.
Response times should align with the severity of the incident as defined in your Incident Response Plan and must satisfy any applicable regulatory or contractual Service Level Agreements.
The organization should designate a qualified Incident Manager or a dedicated Computer Security Incident Response Team (CSIRT) to take ownership of response activities.
By executing predefined technical playbooks that detail steps to isolate affected systems, remove the threat securely, and restore systems from validated backups.
Communications must follow a documented plan that details when to notify management, how to inform impacted customers, and the timeline for reporting to regulatory authorities.
While ISO 27001 requires testing at planned intervals, best practice dictates running tabletop exercises at least annually or following significant changes to infrastructure or personnel.
By conducting a post-incident review to extract knowledge and tracking identified gaps or remediation tasks in a corrective action tracker to continually improve security controls.
Auditors typically want to see consistent execution: a documented plan, evidence that incidents were tracked, and follow-up actions completed. WatchDog Security's Compliance Center helps centralize required artifacts (plans, playbooks, exercise records) and link them to incidents and evidence so you can demonstrate repeatable adherence to documented procedures during audits.
A strong incident log captures triage decisions, containment/eradication/recovery actions, timestamps, owners, and post-incident corrective actions. WatchDog Security's Risk Register can be used to track incident-driven risks and remediation actions with ownership and status, making it easier to show that lessons learned resulted in managed treatments and ongoing follow-up.
| Version | Date | Author | Description |
|---|---|---|---|
| 1.0.0 | 2026-02-17 | WatchDog Security GRC Team | Initial publication |
