Security Incident Response
Security incidents will happen. Even well-protected systems face breaches, data leaks, or compromised credentials. What separates good organizations from bad ones isn't whether incidents occur — it's how they respond.
Incident Response Phases
Effective incident response follows a structured process:
Preparation happens before any incident. Document your response procedures. Identify who to contact. Ensure you have the tools and access needed to investigate. Practice with tabletop exercises.
Detection identifies that something is wrong. This might come from automated alerts, user reports, or external notification. The faster you detect incidents, the less damage occurs.
Containment stops the bleeding. If credentials are compromised, revoke them. If a server is breached, isolate it from the network. The goal is preventing further damage while preserving evidence.
Eradication removes the threat entirely. Patch the vulnerability that was exploited. Remove any malware or backdoors. Ensure attackers can't simply return.
Recovery restores normal operations. Bring systems back online. Verify everything works correctly. Monitor closely for signs the threat persists.
Lessons learned improves future response. What happened? How did we detect it? What worked well? What should we do differently?
During an Incident
When you discover a security incident, stay calm. Panic leads to mistakes that make things worse.
Document everything. Record what you observe, what actions you take, and when. This timeline is invaluable for understanding what happened and may be legally required.
Communicate appropriately. Notify the right people — your security team, management, legal if needed. Be careful about public communication until you understand the scope.
Preserve evidence. Don't immediately wipe compromised systems. Take snapshots, capture logs, and preserve anything that might explain what happened. You may need this for investigation or legal proceedings.
Don't make it worse. Avoid actions that could tip off attackers or destroy evidence. If you're unsure whether an action is safe, ask before proceeding.
Post-Incident Activities
After the immediate crisis, conduct a thorough review:
Build a timeline of events from initial compromise through detection and response. Understanding the sequence reveals where defenses failed.
Perform root cause analysis. Don't stop at "attacker exploited vulnerability." Ask why that vulnerability existed, why it wasn't detected, and why defenses didn't prevent exploitation.
Document what worked and what didn't. Did alerts fire appropriately? Were response procedures clear? Did you have the access and tools needed?
Create action items to prevent recurrence. These should be specific, assigned, and tracked to completion.
Update your runbooks with lessons learned. Future incidents should benefit from this experience.