Incident Response - A Step-by-Step Cyber Attack Plan

About 2 min read

Incident response is an organized process for minimizing damage and recovering quickly when a security incident occurs. NIST SP 800-61 defines four phases: "Preparation," "Detection and Analysis," "Containment, Eradication, and Recovery," and "Post-Incident Activity," with the SOC team taking the lead in driving the response. As of 2025, with the rise in ransomware attacks, establishing an incident response plan is recognized as a management-level priority.

Real-World Use Cases

"Late on a Friday night we detected a ransomware infection and urgently convened the incident response team. Following the playbook, we isolated the infected devices from the network within 30 minutes and completed recovery from backups over the weekend. By Monday morning we had resumed normal operations."

Incident Response Flow

Practice Across the Four Phases

In the preparation phase, you build response procedures (playbooks), establish communication channels, and prepare forensic tools. In the detection and analysis phase, you triage alerts from SIEM and reports from users to identify the scope of impact. In containment, you isolate infected devices from the network and deactivate accounts; in eradication, you completely remove malware and rebuild systems. In post-incident activity, you conduct root cause analysis (RCA) and formulate measures to prevent recurrence.practical guides to incident response (Amazon) let you learn this systematically.

Common Misconceptions and Pitfalls

The misconception that "incident response is solely the IT department's job" is dangerous. The involvement of public relations (media handling), legal (compliance with personal data protection laws), and management (decision-making) is essential, and roles must be clearly assigned in advance. Moreover, there are many cases where evidence is destroyed in a panic when an incident occurs, so it is important to make all employees aware of the principle of "preserving the logs first." With responding to a data breach, there are cases where you are obligated to report to the authorities within 72 hours, making it a race against time.

Preparing at the Individual Level

Account takeover and phishing damage can happen to individuals too. Protect each account by setting a unique, strong password for every service, and learn the steps of incident response for individuals in advance so that you can change your password immediately in the event of a leak.books on CSIRT operations (Amazon) are also helpful references.