Builds a structured ransomware incident response playbook aligned with the CISA StopRansomware Guide and NIST Cybersecurity Framework. Covers preparation, detection, containment, eradication, recovery, and post-incident phases with actionable checklists. Activates for requests involving ransomware response planning, CISA compliance, incident response playbook creation, or ransomware preparedness assessment.
Do not use as a substitute for legal counsel regarding ransom payment decisions, breach notification timelines, or regulatory obligations specific to your jurisdiction.
Establish ransomware-specific defenses before an incident:
CISA Preparation Checklist:
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[ ] Maintain offline, encrypted backups tested for restoration
[ ] Create and exercise a cyber incident response plan (IRP)
[ ] Implement network segmentation between IT and OT networks
[ ] Enable MFA on all remote access and privileged accounts
[ ] Deploy endpoint detection and response (EDR) on all endpoints
[ ] Disable or restrict RDP; require VPN for remote access
[ ] Maintain a software/hardware asset inventory
[ ] Apply patches within 48 hours for internet-facing systems
[ ] Configure email filtering and disable macro execution by default
[ ] Conduct regular phishing awareness training
[ ] Implement application allowlisting (AppLocker/WDAC)
[ ] Test backup restoration quarterly and document RTO/RPO
Identify ransomware indicators and assess scope:
Detection Indicators:
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- Mass file rename operations with new extensions (.locked, .encrypted)
- Ransom notes appearing in directories (README.txt, DECRYPT.html)
- Volume Shadow Copy deletion (vssadmin delete shadows)
- Abnormal CPU usage from encryption processes
- EDR/AV alerts for known ransomware signatures
- Network connections to known C2 infrastructure
- Unusual lateral movement via SMB or PsExec
- Sysmon Event ID 11 (file creation) spikes
Initial Analysis Steps (CISA):
1. Take system images and memory captures of affected devices
2. Identify patient zero and initial access vector
3. Determine the ransomware family (ID Ransomware, ransom note analysis)
4. Assess encryption scope: which systems, shares, and data are affected
5. Check if data exfiltration occurred (double extortion indicator)
Stop the spread and preserve evidence:
Immediate Containment (First 1-4 hours):
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1. Isolate affected systems from the network (disable NICs, VLAN quarantine)
2. If unable to disconnect, power down affected systems
3. Disable shared drives to prevent encryption spread
4. Reset credentials for compromised accounts (especially admin/service accounts)
5. Block known ransomware IOCs at firewall/proxy (C2 domains, IPs)
6. Preserve forensic evidence (memory dumps, disk images, logs)
7. Engage legal counsel and prepare breach notification if data exfiltrated
Extended Containment:
- Identify and patch the initial access vector (phishing, RDP, VPN vuln)
- Audit all Active Directory accounts for persistence (scheduled tasks, services)
- Check for backdoors or additional malware beyond the ransomware payload
Remove the threat and restore operations:
CISA Recovery Steps:
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1. Rebuild affected systems from known-clean images (do NOT decrypt in place)
2. Restore data from offline backups (verify backup integrity first)
3. Reset ALL passwords including service accounts, krbtgt (twice, 12h apart)
4. Scan restored systems with updated AV/EDR before reconnecting to network
5. Re-enable services in priority order based on business criticality
6. Monitor restored systems intensively for 72 hours for reinfection
Recovery Priority Matrix:
P1 (0-4h): Domain controllers, DNS, authentication infrastructure
P2 (4-24h): Email, critical business applications, databases
P3 (1-3d): File servers, departmental applications
P4 (3-7d): Non-critical systems, development environments
Document lessons learned and improve defenses:
Post-Incident Report Template:
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1. Executive summary: What happened, impact, resolution
2. Timeline: Detection to full recovery with timestamps
3. Root cause analysis: Initial access vector and propagation path
4. Scope: Number of systems, data volumes, business impact in hours/dollars
5. Response effectiveness: What worked, what failed, what was missing
6. Recommendations: Specific technical and procedural improvements
7. Compliance actions: Notification timeline, regulatory obligations met
8. Updated playbook: Revisions based on lessons learned
| Term | Definition |
|---|---|
| CISA StopRansomware Guide | Joint CISA/MS-ISAC/NSA/FBI guide providing ransomware prevention best practices and response checklists |
| RTO/RPO | Recovery Time Objective (max downtime) and Recovery Point Objective (max data loss); critical metrics for backup planning |
| Double Extortion | Ransomware tactic where attackers both encrypt data and threaten to publish stolen data unless paid |
| Patient Zero | The first system compromised in an incident; identifying it reveals the initial access vector |
| Tabletop Exercise | Simulated incident scenario walked through by the response team to validate the playbook without live systems |