Responding to Information Security Incidents
ISO 27001 control 5.27 Learning from Information Security Incidents helps produce a robust, well-documented, and communicated incident response process, essential for protecting organisational assets, ensuring operational continuity, and maintaining stakeholder trust.
Preparing for and executing an effective response can mitigate the damage caused by incidents and prevent future occurrences.
Table of Contents
Purpose of Incident Response
The objectives of an effective incident response process include:
- Containment and Mitigation: Limiting the spread and impact of incidents.
- Recovery and Restoration: Ensuring swift restoration of operations and services.
- Learning and Improving: Identifying vulnerabilities and implementing preventive measures.
A structured and proactive approach to incident response allows organisations to minimise disruptions, reduce risk, and strengthen their security posture.
Key Components of an Incident Response Plan
An effective incident response process includes several critical elements:
1. Documented Procedures
Organisations must maintain clear, comprehensive procedures for incident response. These should include:
- Incident Categorisation: Defining criteria to assess severity and scope.
- Response Activities: Establishing specific actions for each phase of the response.
- Communication Protocols: Clearly outlining responsibilities for internal and external reporting.
2. Designated Incident Response Team
A dedicated team with the necessary skills and tools is essential. Responsibilities include:
- Containment: Isolating affected systems to prevent further impact.
- Evidence Collection: Gathering data for analysis and potential legal action.
- Stakeholder Communication: Keeping relevant parties informed while adhering to the need-to-know principle.
3. Escalation and Coordination
Effective escalation ensures timely intervention and resource allocation. Key activities include:
- Activating Crisis Management Plans: When incidents escalate to a critical level.
- Engaging External Parties: Collaborating with authorities, suppliers, or industry experts as needed.
4. Detailed Documentation
Accurate and thorough documentation during incidents is crucial for:
- Accountability: Maintaining a clear record of actions taken.
- Post-Incident Analysis: Enabling root cause investigation and process improvement.
Steps in the Incident Response Process
- Contain the Incident
- Isolate affected systems to prevent further spread.
- Implement temporary security measures to stabilise the environment.
- Notify Stakeholders
- Inform internal teams and external parties, as required.
- Provide timely updates while safeguarding sensitive information.
- Investigate and Analyse
- Conduct forensic analysis to determine the origin and impact of the incident.
- Identify vulnerabilities or misconfigurations that contributed to the issue.
- Resolve and Recover
- Apply fixes or patches to eliminate the root cause.
- Restore affected systems and data to normal operation.
- Document and Close
- Officially close the incident after all actions are completed.
- Create a detailed incident report for future reference.
- Review and Improve
- Conduct a post-incident review to identify lessons learned.
- Update policies, processes, and training to address gaps.
Best Practices for Incident Response
- Regular Training: Keep staff informed and prepared with up-to-date training on incident response procedures.
- Frequent Testing: Conduct drills and simulations to validate the effectiveness of your response plan.
- Leverage Technology: Use advanced tools for detection, analysis, and response automation.
- Build Relationships: Foster collaboration with external partners, authorities, and industry groups.
- Continuous Evaluation: Update and refine response plans to address evolving threats and organisational changes.
FAQs
What is the purpose of Control 5.27: Learning from Information Security Incidents?
The goal of this control is to ensure that valuable lessons are identified, documented, and applied following an information security incident. The aim is not just to resolve incidents, but to prevent recurrence, improve controls, and strengthen the organisation’s overall security posture.
What types of incidents should be reviewed for lessons learned?
All security incidents, regardless of scale, should be reviewed. This includes:
– Malware or ransomware attacks
– Data leaks or unauthorised disclosures
– Social engineering or phishing attempts
– Access control failures
– Misconfigurations or system outages caused by security lapses
Even near misses or low-impact incidents can provide valuable insights.
What is a ‘lessons learned’ review and what should it include?
A lessons learned review is a structured reflection on the incident. It should cover:
– Root cause analysis (e.g. human error, process failure)
– What went well and what didn’t during detection, response, and recovery
– Recommendations for improvement (e.g. technical controls, training, policy updates)
– Assignment of follow-up actions and deadlines
– How the incident and lessons were communicated internally
How should lessons learned be documented and tracked?
Organisations should:
– Maintain a lessons learned register
– Record incidents and outcomes in the incident log
– Assign responsible owners and due dates for actions
– Include lessons in awareness training or process reviews
– Review implementation progress in management reviews or audits
Who is responsible for conducting post-incident learning?
Typically, the Information Security Manager, Incident Response Team, or Risk/Compliance function leads the review. However, it should involve all relevant stakeholders—such as system owners, IT support, HR, or legal—depending on the incident’s nature.
Conclusion
A robust incident response process is a vital component of organisational resilience. By establishing clear procedures, assembling a skilled response team, and committing to continuous improvement, organisations can effectively manage incidents, protect their assets, and enhance overall security. Proactive incident management not only mitigates risks but also provides valuable insights for strengthening defences and fostering long-term growth.
