Data Breach: What to Do

TL;DR

This guide tells you what steps to take if your organisation has suffered a data breach. It covers identifying the breach, containing it, assessing the damage, informing people affected (including regulators), and learning from the incident.

1. Identify the Breach

1. Confirm it’s a breach: Don’t panic! Investigate unusual activity thoroughly before declaring a breach. Look for things like unexpected data access, changes to files, or suspicious network traffic.
2. Gather information: What systems were affected? What type of data was involved (names, addresses, financial details)? When did it happen? How long did it last? Who discovered it?
3. Document everything: Keep a detailed log of all actions taken and findings. This is crucial for legal and regulatory purposes.

2. Contain the Breach

1. Isolate affected systems: Disconnect compromised servers or networks to prevent further spread.
2. Change passwords: Reset passwords for all accounts that may have been accessed, especially privileged ones. Consider multi-factor authentication (MFA).
3. Patch vulnerabilities: Apply security updates to address the weaknesses exploited in the breach. Use a vulnerability scanner if available.

   sudo apt update && sudo apt upgrade

   (example for Debian/Ubuntu)

4. Review firewall rules: Ensure your firewall is properly configured to block malicious traffic.

3. Assess the Damage

1. Data scope: Determine exactly which data was compromised and how many individuals are affected.
2. Impact assessment: What harm could this breach cause to individuals (financial loss, identity theft)?
3. Legal review: Consult with legal counsel to understand your obligations under relevant data protection laws (e.g., GDPR, Data Protection Act 2018).

4. Inform Affected Parties

1. Regulators: Report the breach to the Information Commissioner’s Office (ICO) within 72 hours if it meets the reporting threshold. You can do this via their website: https://ico.org.uk
2. Individuals: Notify affected individuals as soon as possible, explaining what happened, what data was compromised, and what steps they should take to protect themselves (e.g., change passwords, monitor credit reports). Provide clear contact information for support.
3. Law enforcement: Consider reporting the breach to the police or relevant cyber crime unit.

5. Learn from the Incident

1. Root cause analysis: Identify how the breach occurred and what weaknesses allowed it to happen.
2. Improve security measures: Implement changes to prevent similar breaches in the future (e.g., stronger passwords, MFA, regular security training, improved monitoring).
3. Incident response plan: Update your incident response plan based on lessons learned from this breach. Regularly test and review the plan.
4. Cyber insurance: Review your cyber insurance policy to understand coverage for data breaches.