Preparing and executing the incident response plan for information security incidents
The plan
The incident response plan operationalises the policy. Typical contents: purpose, scope and activation criteria; severity definitions and response targets; roles, deputies and 24/7 contact routes; escalation and notification matrix; playbooks for common scenarios (ransomware, phishing, lost device, insider, DDoS); communication templates for staff, customers, regulators and media; evidence handling instructions; tooling and access; and a testing schedule.
Preparation
Preparation is evidence-based: tabletop exercises, simulations, red-team or penetration-test findings and review of past incidents. Test contact data, the out-of-hours route and decision authority, not just technical playbooks. Train first responders to preserve volatile evidence before rebuilding.
Execution
On activation: confirm and declare, appoint an incident manager, open a log, agree an initial severity, set a communication cadence, contain proportionately, eradicate, recover with validation and enhanced monitoring, then close with a handover. Decisions and timestamps are recorded as they happen.
Worked example
Ransomware encrypts a file server. The playbook says isolate, not shut down, to preserve memory; the incident manager declares major severity, invokes the BCP for the affected service, notifies the insurer and legal, and restores from an offline backup verified clean. Recovery is validated by business owners before closure.
Traps
A plan that has never been exercised. Contact lists held only in the tool the incident took offline. Wiping and rebuilding before evidence is captured. Closing at restoration without lessons learned.