Medusa: Forensic Reverse-Engineering & Architectural Dossier

Medusa is a targeted enterprise ransomware platform written in C++ (MSVC). The binary employs Windows I/O Completion Ports (IOCP) to achieve high-throughput file encryption across local drives and network shares. The payload includes an extensive blacklist of 280+ services and 150+ processes associated with databases, virtualization, and endpoint security. Files are encrypted via AES-256 in CBC mode, with the session key encapsulated using an embedded RSA public key.

{
  "-v": "Verbose execution mode; allocates an interactive Win32 console via AllocConsole.",
  "-n": "Enables network share enumeration via WNetOpenEnumW and traverses reachable SMB volumes.",
  "-f": "Fast mode; prioritizes database, virtual machine, and enterprise data extensions.",
  "-p": "Restricts encryption scope strictly to the designated folder path.",
  "-s": "Safe mode reboot parameter; registers a RunOnce key and forces system reboot into Safe Mode.",
  "-k": "Custom campaign or affiliate identifier tag embedded into dropped ransom notes.",
  "-log": "Directs file-level processing telemetry and error states to a local log file."
}

{
  "description": "Binary configuration struct embedded within the .data section, decrypted using a 16-byte XOR key during startup",
  "fields": [
    "0x00: RSA public key modulus and exponent in CryptoAPI PUBLICKEYBLOB format",
    "0x210: 4-byte CRC32 verification checksum",
    "0x214: Array of 280+ service blacklist strings (null-delimited): vss, sqlservr, veeam, exchange, backup",
    "0x850: Array of 150+ process blacklist strings: sqlservr.exe, oracle.exe, msmdsrv.exe, synctime.exe",
    "0xD20: Whitelist directory paths: Windows, Program Files, AppData\\Local\\Temp, System Volume Information",
    "0xEE0: Whitelist file extensions: .exe, .dll, .sys, .medusa, .lnk",
    "0x1050: Ransom note filename: !!!READ_ME_MEDUSA!!!.txt",
    "0x1080: Base64-encoded ransom note text template including Tor negotiation URL and support instructions"
  ]
}

{
  "initialization": "Decrypts configuration block in .data section via XOR loop. Resolves dynamic Win32 APIs via MurmurHash2 hashes. Parses CLI flags (-v, -n, -f, -p).",
  "securityImpairment": "Executes shell commands to disable Microsoft Defender: powershell -Command \"Set-MpPreference -DisableRealtimeMonitoring $true\". Clears event logs via wevtutil cl.",
  "backupDestruction": "Purges backup catalogs and shadow volumes via vssadmin Delete Shadows /All /Quiet, wbadmin DELETE SYSTEMSTATEBACKUP, and wmic shadowcopy delete.",
  "serviceAndProcessSweeper": "Iterates through Service Control Manager, issuing SERVICE_CONTROL_STOP to 280+ identified services. Enumerates running processes and terminates target PIDs using OpenProcess and TerminateProcess.",
  "concurrencyAndIOCP": "Spawns IOCP file handling queue. Producer threads traverse filesystem using FindFirstFileW/FindNextFileW and WNetOpenEnumW for SMB shares. Worker pool (2 * cores + 2) pops file descriptors.",
  "cryptographicProcessing": "Generates 32-byte AES key and 16-byte IV via BCryptGenRandom. Performs AES-256-CBC encryption. Appends RSA-encrypted session key, IV, CRC32, and MEDUSA_LOCKED header at EOF. Renames file to .MEDUSA.",
  "extortionDeployment": "Drops !!!READ_ME_MEDUSA!!!.txt in each processed folder. Displays ransom text in allocated console if -v flag is present."
}

Concrete technical breakdown of functional modules implemented in the Medusa binary:

Medusa operates a centralized Tor V3 Onion leak portal (Medusa Blog) where victim details, stolen data previews, and countdown timers are published. Affiliates utilize public and private Telegram channels to broadcast victim claims and communicate negotiation status. Victim interactions are managed via private chat portals authenticated with tokens dropped in the ransom note.

Indicators of compromise and forensic patterns recorded across laboratory triage: