How to Create a Cyber Incident Response Plan

📘 Chapter 3: Developing the Incident Response Lifecycle

🔐 Introduction

An incident response plan without a defined lifecycle is like a fire drill without instructions. It may raise awareness but fails to guide action during a real crisis. The Incident Response Lifecycle (IRL) brings structure to chaos by outlining the phases, processes, and priorities every organization must follow during and after a cyber incident.

In this chapter, we’ll explore the six essential phases of an incident response lifecycle, aligned with the NIST SP 800-61 framework, covering practical actions, key tools, decision points, and documentation strategies. Whether you’re managing phishing attempts, insider data leaks, or a ransomware outbreak, this lifecycle turns panic into protocol.

🔁 The Six Phases of the Incident Response Lifecycle

1️⃣ Preparation: Building Your Defensive Foundation

This is the most critical phase, as it lays the groundwork for all other actions.

✅ Core Activities:

• Develop and maintain the Cyber Incident Response Plan (CIRP)
• Assign roles and responsibilities (CIRT setup)
• Maintain updated asset inventory
• Configure logging, monitoring, and alerting systems (SIEM, EDR)
• Conduct security awareness training and phishing simulations
• Prepare and secure communication channels (email, VoIP, messaging)
• Define severity levels and incident classification standards

🔐 A strong preparation phase prevents 80% of avoidable incident chaos.

2️⃣ Identification: Spotting the Threat Early

This phase answers: “Is something wrong? What kind of incident is this?”

✅ Core Activities:

• Monitor SIEM, EDR, IDS/IPS, and firewall logs for anomalies
• Triage alerts to rule out false positives
• Correlate findings with threat intelligence (IOC feeds)
• Gather context: attack vector, affected systems, severity, scope
• Document incident ticket and notify relevant CIRT members

🚦 Incident Severity Classification (Example)

3️⃣ Containment: Stop the Bleeding

Containment prevents attackers from spreading or exfiltrating further.

✅ Containment Types:

• Short-term containment: Quickly isolate affected systems
• Long-term containment: Patch systems, reset credentials, reconfigure access controls

✅ Core Activities:

• Disconnect infected endpoints from the network
• Disable compromised user accounts or services
• Block malicious domains/IPs
• Notify internal stakeholders
• Preserve forensic data (memory dumps, logs, disk images)

⚠️ Balance speed with evidence preservation — don’t wipe data prematurely.

4️⃣ Eradication: Remove the Threat

Once containment is achieved, the focus shifts to removing the root cause of the incident.

✅ Core Activities:

• Remove malware, rootkits, or unauthorized software
• Re-image compromised systems if needed
• Scan for backdoors and persistence mechanisms
• Apply patches and security updates
• Change passwords and rotate credentials
• Validate systems with malware scanners and forensic tools

5️⃣ Recovery: Resume Operations Safely

Recovery focuses on restoring systems to normal operations and validating that systems are clean and secure.

✅ Core Activities:

• Restore affected systems from clean, verified backups
• Monitor systems post-restoration for unusual behavior
• Resume production environment in stages (if needed)
• Perform network scans for signs of lateral movement
• Validate business continuity and stakeholder communication

6️⃣ Lessons Learned: Turn Failure Into Future Strength

Every incident is a learning opportunity. Don’t skip this phase.

✅ Core Activities:

• Conduct a post-incident review (“retrospective” or “post-mortem”)
• Document what worked and what didn’t
• Update response plans, detection rules, playbooks
• Share lessons with stakeholders and regulatory bodies (if required)
• Train teams based on updated procedures

📌 Record findings in a central incident knowledge base for reference.

🎯 Mapping the IR Lifecycle to Common Attacks

📊 Incident Response Lifecycle Checklist

🧠 Summary

The Incident Response Lifecycle transforms panic into process. By defining clear phases, actions, and tools, your organization gains the ability to respond faster, contain more effectively, and bounce back stronger.

An effective lifecycle is:

• Role-driven
• Tool-assisted
• Tested regularly
• Adapted to your infrastructure

Remember, cyber incidents are inevitable — but disaster is optional when your lifecycle is repeatable, rehearsed, and resilient.