Incident Response Planning: How to Prepare for a Cyber Attack
A security breach isn't a matter of "if" but "when." The organizations that survive incidents with minimal damage aren't the ones with the biggest budgets — they're the ones with a tested plan. An incident response (IR) plan is your playbook for detecting, containing, and recovering from security events before they escalate into full-blown crises.
The 6 Phases of Incident Response
The NIST Cybersecurity Framework outlines six phases that form the backbone of any effective IR plan:
1. Preparation
Build your IR team, define roles and responsibilities, establish communication channels, deploy monitoring tools, and create runbooks for common incident types. Preparation also means ensuring you have forensic tools, backup systems, and legal counsel on standby before an incident occurs.
2. Identification
Detect and confirm that a security event is actually an incident. This requires functioning monitoring — SIEM alerts, endpoint detection, network anomaly detection, and user reports. The faster you identify an incident, the smaller the blast radius. Define clear criteria for what constitutes an incident versus normal operations.
3. Containment
Stop the bleeding. Short-term containment isolates affected systems to prevent lateral movement — network segmentation, account disabling, firewall rules. Long-term containment keeps business running while you investigate — standing up clean systems, rerouting traffic, applying temporary patches.
4. Eradication
Remove the threat completely. This means identifying the root cause — not just the symptoms. Eradication may involve removing malware, closing exploited vulnerabilities, resetting compromised credentials, and rebuilding affected systems from known-good images.
5. Recovery
Restore systems to normal operations with confidence. Validate that the threat is gone, restore from clean backups, monitor closely for re-infection, and gradually return systems to production. Recovery isn't instant — it requires careful validation at each step.
6. Lessons Learned
Conduct a blameless post-incident review within 72 hours. Document what happened, what worked, what didn't, and what changes are needed. Update your IR plan, detection rules, and runbooks based on real-world experience. This is the phase most organizations skip — and it's the most valuable.
Building Your Incident Response Team
An effective IR team includes more than just security engineers. You need:
- Incident Commander: Owns the response, makes decisions, manages communication between teams.
- Security Analysts: Perform triage, investigation, and forensic analysis.
- IT Operations: Execute containment and recovery actions — network changes, system rebuilds, backup restoration.
- Legal Counsel: Advises on regulatory notification requirements, evidence preservation, and liability.
- Communications Lead: Manages internal and external messaging — employees, customers, press, regulators.
- Executive Sponsor: Authorizes resources, approves major decisions like system shutdowns or public disclosure.
Tabletop Exercises: Testing Without the Crisis
A plan that hasn't been tested is a plan that won't work. Tabletop exercises walk your IR team through realistic scenarios — a ransomware attack, a data breach, a compromised vendor — in a conference room, not a war room. Participants discuss what they would do at each decision point, revealing gaps in procedures, unclear ownership, and communication breakdowns.
Run tabletop exercises at least twice a year. Vary the scenarios. Include leadership. The goal isn't to follow the plan perfectly — it's to find where the plan fails so you can fix it before a real incident forces you to improvise.
Common Mistakes to Avoid
- No plan at all: Improvising during a breach leads to slower containment, more damage, and higher costs.
- Plan exists but isn't tested: Outdated contact lists, missing runbooks, and untrained staff make the plan useless when it matters.
- Skipping forensics: Rushing to restore systems without understanding root cause often leads to re-compromise within weeks.
- Ignoring communication: Delayed or inconsistent messaging to employees, customers, and regulators compounds the damage.
- No lessons learned: Failing to review and improve after an incident guarantees you'll repeat the same mistakes.
Need help building your incident response capability? DarkHorse InfoSec provides IR planning, tabletop exercises, and 24/7 on-call response retainers.
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