Performing Ransomware Response
When to Use
- Ransomware has been detected executing or file encryption is actively occurring
- Users report inability to open files with unfamiliar extensions appended
- A ransom note is discovered on one or more systems
- EDR detects mass file modification patterns consistent with encryption behavior
- Threat intelligence warns of an imminent ransomware campaign targeting the organization
Do not use for general malware incidents that do not involve file encryption or extortion; use malware incident response procedures instead.
Prerequisites
- Ransomware-specific incident response playbook reviewed and approved by executive leadership
- Tested and verified offline backup strategy with air-gapped or immutable copies
- Incident retainer with a specialized ransomware response firm (e.g., Mandiant, CrowdStrike Services, Kroll)
- Legal counsel pre-engaged for OFAC sanctions screening and regulatory notification
- Cyber insurance carrier contact information and policy coverage details
- Bitcoin/cryptocurrency analysis capability or third-party engagement for payment tracing
Workflow
Step 1: Detect and Confirm Ransomware
Validate that the incident is ransomware and determine the variant:
- Identify the ransomware by analyzing the ransom note filename, extension appended to encrypted files, and note content
- Upload the ransom note and a sample encrypted file to ID Ransomware (id-ransomware.malwarehunterteam.com)
- Check NoMoreRansom.org for available free decryptors
- Determine the ransomware deployment method from EDR/SIEM logs
- Identify the ransomware group (e.g., LockBit, BlackCat/ALPHV, Royal, Akira, Play)
Ransomware Identification:
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Variant: LockBit 3.0 (Black)
Extension: .lockbit3
Ransom Note: README-LOCKBIT.txt
Tor Site: lockbit[redacted].onion
Deployment: Group Policy Object pushing ransomware.exe to all domain-joined systems
Initial Access: VPN credential compromise (no MFA)
Dwell Time: 12 days
Data Exfiltration: Yes - 47GB uploaded to MEGA via rclone prior to encryption
Step 2: Immediate Containment
Stop ransomware propagation before assessing damage:
- Priority 1: Disconnect affected network segments from core infrastructure (pull the network cable, not shutdown)
- Priority 2: Isolate all domain controllers immediately if GPO-based deployment is suspected
- Priority 3: Disable the compromised accounts used for deployment
- Priority 4: Block lateral movement protocols (SMB TCP/445, RDP TCP/3389, WinRM TCP/5985-5986)
- Priority 5: Preserve at least one encrypted system live (do not power off) for memory forensics
- Do NOT: Shut down encrypted systems; keep them powered on to preserve encryption keys in memory
Step 3: Assess Damage and Scope
Quantify the impact to inform recovery and business decisions:
- Count the number of encrypted systems (workstations, servers, domain controllers)
- Determine which business-critical systems and data are affected
- Verify backup integrity: check that backups were not encrypted, deleted, or corrupted
- Assess whether data exfiltration occurred (check for rclone, WinSCP, MEGA, cloud storage activity)
- Determine the ransom demand amount and payment deadline
- Check OFAC sanctions lists to verify the ransomware group is not a sanctioned entity (paying is legally risky)
Impact Assessment:
Encrypted Systems: 187 of 340 endpoints (55%)
Encrypted Servers: 12 of 28 (43%) - includes 2 file servers, 1 database server
Domain Controllers: 2 of 3 encrypted
Backup Status: Veeam repository intact (offline copy verified clean)
Data Exfiltration: Confirmed - 47GB to MEGA (file listing under analysis)
Ransom Demand: $2.5M in Bitcoin (72-hour deadline)
OFAC Screening: LockBit - not currently sanctioned entity (verify with counsel)
Step 4: Recovery Decision Matrix
Evaluate recovery options in consultation with legal, executive leadership, and cyber insurance:
| Option | Pros | Cons | Recommended When |
|---|
| Restore from backup | No payment, no legal risk | Recovery time may be days | Clean backups available |
| Free decryptor | No payment, fast | Rare availability | Variant has published decryptor |
| Negotiate and pay | Potentially faster | No guarantee, legal risk, funds threat actors | No backups, business survival at stake |
| Rebuild from scratch | Clean environment | Longest timeline, data loss | Backups compromised, willing to accept data loss |
Step 5: Execute Recovery
Implement the chosen recovery strategy:
If restoring from backup:
- Build a clean isolated network segment for recovery operations
- Rebuild domain controllers first from clean media (do NOT restore DC backups older than the dwell time)
- Reset ALL user and service account passwords before joining any system to the new domain
- Restore servers in priority order: authentication, DNS, DHCP, then business-critical applications
- Restore workstations via reimaging, not file-level restore
- Restore data from verified clean backups to rebuilt file servers
- Reconnect to production network only after validation
If using a decryptor:
- Test the decryptor on a non-critical system first
- Decrypt in order of business priority
- Scan all decrypted systems for residual malware before reconnection
Step 6: Post-Ransomware Hardening
Implement controls to prevent recurrence:
- Enforce MFA on all remote access (VPN, RDP, cloud portals)
- Implement 3-2-1-1-0 backup strategy (3 copies, 2 media types, 1 offsite, 1 immutable, 0 errors)
- Deploy application whitelisting on servers
- Implement network segmentation between workstation and server VLANs
- Enable Protected Users security group for privileged accounts
- Disable NTLM authentication where possible
- Deploy LAPS (Local Administrator Password Solution) for local admin accounts
Key Concepts
| Term | Definition |
|---|
| Double Extortion | Ransomware tactic combining file encryption with data exfiltration and threat to publish stolen data |
| Immutable Backup | Backup storage that cannot be modified or deleted for a defined retention period, protecting against ransomware targeting backups |
| OFAC Sanctions | U.S. Office of Foreign Assets Control restrictions that may prohibit ransom payments to sanctioned entities or jurisdictions |
| Dwell Time | Days the attacker was present before deploying ransomware; critical for determining which backups are clean |
| Ransomware-as-a-Service (RaaS) | Criminal business model where ransomware developers lease their malware to affiliates who conduct attacks |
| Rclone | Legitimate cloud sync tool commonly abused by ransomware operators for data exfiltration before encryption |
| 3-2-1-1-0 Backup Rule | Backup strategy requiring 3 copies, 2 media types, 1 offsite, 1 immutable/air-gapped, and 0 errors in recovery testing |
Tools & Systems
- ID Ransomware: Online service to identify ransomware variant from ransom note or encrypted file sample
- NoMoreRansom.org: Europol-backed project providing free decryption tools for certain ransomware families
- Veeam / Commvault: Enterprise backup platforms with immutable repository and instant VM recovery capabilities
- KAPE: Rapid forensic triage collection from encrypted systems to determine initial access and dwell time
- Cado Response: Cloud-native forensics platform for investigating ransomware that affects cloud infrastructure
Common Scenarios
Scenario: LockBit 3.0 via Compromised VPN
Context: Attackers compromised VPN credentials (no MFA), spent 12 days performing reconnaissance, disabled antivirus via GPO, exfiltrated 47GB of data, and deployed LockBit 3.0 across the domain via GPO at 2:00 AM on a Sunday.
Approach:
- Disconnect all network segments at the core switch level
- Verify offline backup integrity (Veeam repository on immutable storage)
- Preserve two encrypted servers powered on for memory forensics
- Engage incident response retainer and cyber insurance carrier
- Begin recovery in isolated network: rebuild DCs, reset all passwords, restore in priority order
- Conduct forensic investigation in parallel to determine initial access and full adversary activity
Pitfalls:
- Restoring from backups that were created during the 12-day dwell time (may contain backdoors)
- Paying the ransom without OFAC screening and legal counsel review
- Reconnecting recovered systems to the production network before full password reset
- Not checking for data exfiltration, leaving the organization exposed to the extortion threat
Output Format
RANSOMWARE INCIDENT REPORT
===========================
Incident: INC-2025-1892
Ransomware Family: LockBit 3.0 (Black)
Date Detected: 2025-11-17T06:45:00Z
Initial Access: VPN credential compromise (no MFA)
Dwell Time: 12 days
IMPACT SUMMARY
Encrypted Systems: 187 endpoints, 12 servers
Business Impact: Full operations disruption
Data Exfiltrated: 47GB (finance, HR, legal documents)
Ransom Demand: $2.5M BTC (72-hour deadline)
Backup Status: Veeam immutable repository - CLEAN
RECOVERY APPROACH
Decision: Restore from backup (no ransom payment)
Recovery Start: 2025-11-17T10:00:00Z
DC Rebuild: Complete - 2025-11-17T18:00:00Z
Critical Systems: Restored - 2025-11-18T12:00:00Z
Full Recovery: Estimated 2025-11-21
CONTAINMENT TIMELINE
06:45 UTC - Ransomware detected by SOC analyst
07:00 UTC - Network segments disconnected
07:15 UTC - Incident commander activated IR plan
07:30 UTC - Backup integrity verification started
08:00 UTC - Memory forensics initiated on 2 live systems
10:00 UTC - Recovery operations commenced in clean room
POST-INCIDENT ACTIONS
1. MFA enforced on all VPN and remote access
2. 3-2-1-1-0 backup architecture implemented
3. Network segmentation between workstation/server VLANs
4. LAPS deployed for local administrator passwords
5. Regulatory notifications filed (GDPR 72-hour, state AG)
