Incident Response

Incident response is the structured process an organization follows to detect, analyze, contain, eradicate, and recover from security incidents. An incident response plan (IRP) documents roles, procedures, communication protocols, and escalation paths so the organization can respond quickly and effectively when a security event occurs.

The Incident Response Lifecycle

Based on the widely adopted NIST SP 800-61 framework, the incident response lifecycle includes:

1. Preparation — Establish the incident response team, define roles, acquire tools, and conduct training
2. Detection and analysis — Identify potential incidents through monitoring, alerts, and reports; determine scope and severity
3. Containment — Limit the damage by isolating affected systems, blocking malicious activity, and preserving evidence
4. Eradication — Remove the root cause of the incident (malware, unauthorized access, vulnerable configurations)
5. Recovery — Restore affected systems to normal operation with enhanced monitoring
6. Lessons learned — Conduct a post-incident review to improve future response capabilities

Why It Matters

Every major compliance framework requires incident response capabilities:

ISO 27001 includes controls for incident management planning (A.5.24), assessment and decision (A.5.25), response (A.5.26), and learning from incidents (A.5.27). Auditors verify that the plan exists, is communicated, and has been tested.

SOC 2 Common Criteria CC7.3 through CC7.5 address incident identification, response, and communication. Auditors review incident logs, response procedures, and evidence of plan testing.

HIPAA requires covered entities to identify and respond to suspected or known security incidents and mitigate harmful effects.

NIST CSF dedicates an entire function (Respond) to incident response, with subcategories covering response planning, communications, analysis, mitigation, and improvements.

Best Practices

Test your plan. Conduct tabletop exercises at least annually. Walk through realistic scenarios with your incident response team to identify gaps in procedures and communication.

Define severity levels. Not every security event is a critical incident. Establish clear criteria for severity classification to ensure appropriate resource allocation.

Maintain a communication template. Pre-drafted notifications for customers, regulators, and executives save critical time during an active incident.