Incident Response Plan

An Incident Response Plan (IRP) is a comprehensive playbook that enables organizations to respond to security incidents in a systematic, efficient manner rather than making ad hoc decisions under pressure. The plan typically follows established frameworks such as NIST SP 800-61, which defines six phases: preparation (building capability and readiness), identification (detecting and validating incidents), containment (limiting the scope and impact), eradication (removing the root cause), recovery (restoring systems to normal operation), and lessons learned (improving based on the experience). The IRP should cover various incident scenarios including data breaches, ransomware attacks, denial of service, insider threats, and supply chain compromises.

An incident response plan is explicitly or implicitly required by every major compliance framework. ISO 27001 Annex A controls A.5.24 through A.5.28 address information security incident management planning, assessment, response, learning from incidents, and evidence collection. SOC 2 evaluates whether organizations have defined and tested incident response procedures. GDPR mandates breach notification within 72 hours, which is only achievable with a pre-defined response plan. NIS2 imposes specific incident notification timelines (early warning within 24 hours, full notification within 72 hours, final report within one month) that require a well-rehearsed response capability. In technology due diligence, the existence and maturity of an incident response plan is a key security assessment criterion.

Developing an effective IRP requires more than writing a document. The plan should define clear roles and responsibilities (incident commander, technical responders, communications lead, legal counsel, management stakeholders), establish severity classification criteria that trigger different response levels, include contact lists and escalation paths, define communication templates for internal and external stakeholders, and reference evidence preservation procedures. Critically, the plan must be regularly tested through tabletop exercises (discussion-based scenarios), functional exercises (simulated incidents), and full-scale simulations. Testing reveals gaps in the plan, builds team familiarity with procedures, and improves response times. Post-incident reviews should capture lessons learned and feed improvements back into the plan.