BlackCat / ALPHV: Forensic Reverse-Engineering & Architectural Dossier

BlackCat (ALPHV) is an advanced cross-platform ransomware framework developed in Rust. The platform targets both Windows and Linux/VMware ESXi hypervisors. Binaries utilize the Tokio multi-threaded asynchronous runtime, Clap CLI parser, Serde JSON configuration deserializer, and hardware-accelerated AES-NI / ChaCha20 cryptographic engines. The binary enforces an execution gating mechanism via the mandatory --access-token argument.

{
  "--access-token": "Mandatory 32-byte hexadecimal authorization token; execution aborts immediately without valid token string.",
  "--drag-and-drop": "Enables interactive file/folder drop handler for selective targeted encryption.",
  "--bypass-uac": "Executes programmatic auto-elevation routine via ICMLuaUtil COM interfaces.",
  "--safe-mode": "Configures BCD bootloader with safeboot network and registers persistence service for execution in Safe Mode.",
  "--no-wall": "Suppresses desktop wallpaper replacement routine.",
  "--no-prop-servers": "Suppresses scanning and lateral propagation against domain controllers and network servers.",
  "--no-prop-shares": "Disables enumeration and traversal of network SMB and NFS shares.",
  "--no-net-enum": "Disables local network ARP cache inspection and subnet ping sweeps.",
  "--extra-logging": "Enables detailed debug logging to stdout and designated log files.",
  "-p, --paths": "Specifies an array of explicit filesystem paths targeted for cryptographic operations."
}

{
  "description": "Embedded JSON document compressed and encrypted in binary, decrypted in memory using the supplied --access-token",
  "fields": [
    "public_key: 32-byte Base64-encoded public key (Curve25519 or RSA-4096)",
    "extension: Custom 7-character file extension assigned to affiliate campaign",
    "note_file_name: Name of dropped ransom note (e.g., RECOVER-[extension]-NOTES.txt)",
    "note_full_text: Base64-encoded ransom note template including affiliate negotiation Tor URL",
    "services: Array of service names targeted for termination (e.g., vss, sql, veeam, exchange, backup)",
    "processes: Array of process names targeted for termination (e.g., sqlservr.exe, vmware.exe, postgres.exe)",
    "white_list_strings: Array of directories and files excluded from encryption ($Recycle.Bin, Windows, boot)",
    "encryption_mode: Configured encryption mode (Full, HeadOnly, Dot, Smart)",
    "network_discovery: Boolean toggle governing ARP sweep and SMB share discovery"
  ]
}

{
  "initialization": "Rust runtime initializes Tokio multi-threaded scheduler. Parses CLI switches via Clap. Decrypts internal JSON configuration using the mandatory --access-token.",
  "privilegeEscalation": "Evaluates token integrity level. If non-elevated and --bypass-uac is set, launches elevated COM task via ICMLuaUtil. Enables SeDebugPrivilege and SeBackupPrivilege.",
  "discoveryAndEnumeration": "Enumerates local logical drives, volume GUIDs, and network shares via WNetOpenEnumW unless --no-prop-shares is active. Scans ARP table via GetIpNetTable.",
  "serviceTermination": "Iterates through config.services array, calling OpenServiceW and ControlService(SERVICE_CONTROL_STOP). Iterates through config.processes, terminating matching PIDs via TerminateProcess.",
  "shadowCopyDestruction": "Windows: Executes vssadmin.exe delete shadows /all /quiet, wmic.exe shadowcopy delete, and bcdedit.exe /set {default} recoveryenabled No. ESXi: Invokes esxcli to force-kill VM worlds.",
  "cryptographicProcessing": "Tokio runtime spawns async worker tasks per logical core. Evaluates encryption_mode: Full, HeadOnly, Dot (stride skips), or Smart. Encrypts with ChaCha20 or AES-256-GCM, appends encrypted session key block, and renames file.",
  "ransomNotification": "Drops RECOVER-*-NOTES.txt in traversed directories. Updates desktop background image unless --no-wall is specified."
}

Concrete technical breakdown of functional modules implemented in the BlackCat / ALPHV binary:

Commands and telemetry operate over Tor V3 Onion endpoints mediated via an embedded SOCKS5 proxy layer. Victim negotiation is facilitated through decentralized onion portals where victims authenticate using credentials embedded in dropped ransom notes. Operator communication interfaces with private REST API endpoints on hidden services.

Indicators of compromise and forensic patterns recorded across laboratory triage: