Saving 5TB of Critical Patient Records

At 3:00 AM on a Sunday, a major regional hospital network was struck by a devastating, targeted ransomware attack. Doctors and nurses found themselves locked out of critical Electronic Health Records (EHR), digital X-ray imaging systems, and administrative controls for ICU monitoring.

The screens displayed a ransom note from a known Advanced Persistent Threat (APT) group utilizing a variant of the Ryuk ransomware, demanding $5 Million USD in Bitcoin within 48 hours, or the encryption keys would be destroyed, potentially endangering hundreds of lives.

The ransomware was spreading laterally at terrifying speeds, utilizing SMB exploits (similar to EternalBlue) and compromised Active Directory (AD) credentials. The hospital's legacy antivirus was completely blind to this fileless, memory-resident attack. The primary challenge was to halt the encryption process without turning off the servers, which would destroy volatile memory clues.

• Containment & Triage: Cyberen's 24/7 Incident Response (IR) team was deployed immediately. We instructed the IT staff to physically pull the ethernet cables from the core switches, air-gapping the infected subnets while keeping the machines powered on.
• Endpoint Telemetry & Hunting: We rapidly deployed CrowdStrike Falcon sensors across the remaining network and utilized KAPE (Kroll Artifact Parser and Extractor) to triage the infected machines. Within 2 hours, we identified Patient Zero and the Entry Point: a compromised VPN credential belonging to a third-party HVAC vendor.
• Reverse Engineering: Our malware analysts extracted the ransomware payload from memory. Using Ghidra and IDA Pro, we reverse-engineered the binary, identifying the exact encryption algorithms (AES-256 with RSA) and the Command & Control (C2) IP addresses the malware was attempting to contact.
• Network Forensics: By analyzing traffic captures via Wireshark and ingesting firewall logs into Splunk, we confirmed that while the data was encrypted, the attackers had failed to exfiltrate (steal) the patient records off-site before we severed the connection.

Having isolated the threat and confirmed no data exfiltration had occurred, we focused entirely on recovery. We discovered that while the primary backups were encrypted, an older, air-gapped immutable backup server stored in an off-site bunker remained completely untouched.

We rebuilt the Active Directory from scratch, enforced strict Multi-Factor Authentication (MFA), and safely restored the 5TB database from the isolated backups onto newly secured servers.

The hospital resumed critical emergency operations within 24 hours of our intervention. Zero ransom was paid to the threat actors, saving the hospital millions of dollars and preventing the funding of further cyber-terrorism.