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How to Prevent Ransomware

Comprehensive guide to preventing ransomware attacks through detection, hardening, and response strategies.

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Originally published on Red Canary Blog
Read the full article: How to Prevent Ransomware

Ransomware Kill Chain

Understanding how ransomware operates helps us prevent it:

  1. Initial Access - Phishing, RDP, vulnerabilities
  2. Execution - Malicious payloads run
  3. Persistence - Maintain access
  4. Privilege Escalation - Gain admin rights
  5. Credential Access - Steal credentials
  6. Lateral Movement - Spread through network
  7. Encryption - Encrypt files
  8. Exfiltration - Steal data (double extortion)

Prevention Strategies

Block Initial Access

  • Email filtering and sandboxing
  • Patch management
  • Disable unnecessary RDP
  • VPN with MFA
  • Application whitelisting

Detect Early Execution

Monitor for:

  • Suspicious process execution
  • PowerShell abuse
  • Script execution
  • Unusual network connections

Limit Lateral Movement

  • Network segmentation
  • Least privilege access
  • Disable SMBv1
  • Monitor credential usage
  • Restrict admin accounts

Prevent Encryption

  • Behavioral monitoring for mass file changes
  • Backup critical data (offline/immutable)
  • File integrity monitoring
  • Honeypot files

Detection Opportunities

Pre-Encryption Indicators

  • Reconnaissance activity
  • Credential dumping
  • Tool deployment
  • Backup deletion
  • Shadow copy deletion

Encryption Indicators

  • Rapid file modifications
  • File extension changes
  • Ransom note creation
  • Unusual process behavior

Response Planning

Before Ransomware

  • Incident response plan
  • Backup strategy (3-2-1 rule)
  • Communication plan
  • Legal/PR preparation

During Ransomware

  • Isolate affected systems
  • Preserve evidence
  • Assess scope
  • Execute recovery plan

After Ransomware

  • Root cause analysis
  • Improve defenses
  • Update procedures
  • Share lessons learned

Critical Controls

  1. Backups - Offline, immutable, tested
  2. Patching - Rapid vulnerability remediation
  3. MFA - On all remote access
  4. EDR - Behavioral monitoring
  5. Network Segmentation - Limit spread

Read the full prevention guide: How to Prevent Ransomware

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