Ransomware is a type of malicious software (malware) designed to block access to a computer system or encrypt its data, effectively rendering the system or files inaccessible to the user. The attacker then demands a ransom payment, usually in cryptocurrency, to restore access or decrypt the data.

Proactive Prevention

• Regular Backups
  • Implement a regular backup schedule.
  • Ensure backups are stored offline or on a separate network.
• Patch Management
  • Regularly update and patch the operating system and all software to close vulnerabilities.
• Access Controls
  • Use the principle of least privilege (PoLP) to limit user access rights.
  • Implement strong password policies and use multi-factor authentication (MFA).
• Network Segmentation
  • Segment your network to limit the spread of ransomware.
• Anti-Malware Software
  • Use and regularly update anti-malware software.
• Email Filtering
  • Implement email filtering to block malicious attachments and links.
• Firewalls and Intrusion Detection/Prevention Systems (IDS/IPS)
  • Configure firewalls to block unauthorized access.
  • Use IDS/IPS to detect and prevent malicious activity.
• User Education
  • Educate users about the risks of phishing and social engineering.

Reactive Response

• Isolate Infected Systems
  • Immediately disconnect infected systems from the network to prevent the spread.
• Incident Response Plan
  • Have a clear incident response plan in place.
  • Identify and contain the infection, and begin recovery processes.
• Forensics
  • Perform a forensic analysis to understand how the ransomware entered the system.
• Restore from Backups
  • Restore data from clean backups.
  • Ensure that the restored system is clean before reconnecting it to the network.
• Report and Learn
  • Report the incident to appropriate authorities.
  • Conduct a post-incident review to improve defenses.

Tools and Resources

• Backup Solutions: rsnapshot, Bacula, Duplicity
• Patch Management: Unattended Upgrades, Landscape for Ubuntu
• Access Control Tools: sudo, SELinux, AppArmor
• Anti-Malware: ClamAV, Sophos for Linux
• Firewalls: iptables, nftables, ufw
• IDS/IPS: Snort, Suricata