Meduza Stealer: Forensic Reverse-Engineering & Architectural Dossier

{
  "compiler": "MSVC (link.exe /OPT:REF /OPT:ICF /NODEFAULTLIB)",
  "runtime": "Native Win32 C++ runtime with custom CRT stub implementation to minimize import table footprint",
  "binary_footprint": "Single PE32/PE32+ executable, 180 KB - 320 KB uncompressed native payload",
  "stub_size": "245,760 bytes (unpacked standard build); payload expanded when wrapped in commercial crypters",
  "packer_obfuscation": "Often delivered via custom loader stagers, in-memory reflective DLL injection, or packed with XOR/AES crypters",
  "subsystem": "Windows GUI (Subsystem 2)",
  "entry_point_flow": "WinMain -> Dynamic API Resolution (PEB traversal / CRC32 hashing) -> CIS Geolocation & Keyboard Language Check -> Anti-Analysis & Debugger Probing -> Master Key Decryption (DPAPI) -> In-Memory SQLite Database Parsing -> Crypto Wallet & Browser Artifact Aggregation -> In-Memory Deflate Compression -> RC4/AES-CBC Encryption -> HTTPS POST Exfiltration -> Self-Deletion via cmd.exe /c del",
  "technical_summary": "Meduza Stealer is a specialized, lightweight information stealer implemented in C++. Engineered specifically for rapid endpoint execution without dropping auxiliary helper DLLs, Meduza parses SQLite database structures directly from memory without relying on sqlite3.dll. It targets over 100 Chromium and Gecko-based web browsers, 40+ cryptocurrency browser extension wallets, desktop cold storage files, 2FA desktop authenticators, and messaging application sessions. Pre-execution routines enforce strict geofencing checks, terminating immediately if CIS country identifiers are detected."
}

{
  "interface_type": "SaaS Web Dashboard / Operator Panel",
  "builder_tabs_options": [
    {
      "tab": "Dashboard & Telemetry",
      "options": [
        "Real-time victim stream displaying HWID, IP geolocation, OS build, and infected timestamp",
        "Automated wallet tally enumerating detected MetaMask, Phantom, TronLink, and cold storage seeds",
        "Global map visualizer displaying geographical victim spread"
      ]
    },
    {
      "tab": "Build Configurator",
      "options": [
        "C2 Gateway URL: Primary HTTPS listener host specification",
        "Affiliate Tag: Custom alphanumeric tracking token",
        "CIS Geoblocking Gate: Enforce automatic termination on CIS keyboard/locale discovery",
        "Module Selector: Toggles for Chromium, Gecko, Crypto Wallets, 2FA, Discord, Telegram, File Grabber"
      ]
    },
    {
      "tab": "Log Repository",
      "options": [
        "Direct ZIP download of individual harvested credential archives",
        "Integrated search for domain keywords (banking, cryptocurrency exchanges, corporate SSO)",
        "Automated parsing of extracted cookies into Netscape/JSON format"
      ]
    }
  ],
  "config_struct_layout": [
    {
      "offset": "0x00",
      "field": "Magic",
      "type": "DWORD",
      "description": "Binary magic identifier (0x4D45445A // 'MEDZ')"
    },
    {
      "offset": "0x04",
      "field": "BuildVersion",
      "type": "DWORD",
      "description": "Stealer engine version (e.g., 0x00020001 // v2.1)"
    },
    {
      "offset": "0x08",
      "field": "BuildID",
      "type": "CHAR[32]",
      "description": "Affiliate tracking tag"
    },
    {
      "offset": "0x28",
      "field": "C2_GateURL",
      "type": "CHAR[128]",
      "description": "HTTPS exfiltration gate URL"
    },
    {
      "offset": "0xA8",
      "field": "EncryptionKey",
      "type": "BYTE[32]",
      "description": "Symmetric encryption seed key (RC4 / AES)"
    },
    {
      "offset": "0xC8",
      "field": "FeatureFlags",
      "type": "DWORD",
      "description": "Bitmask for targeted data artifacts (Browsers, Wallets, 2FA, Tokens)"
    },
    {
      "offset": "0xCC",
      "field": "GeoExclusionMask",
      "type": "DWORD",
      "description": "Bitmask for blocked locale IDs and country codes"
    }
  ],
  "payload_generation_flags": [
    "/NODEFAULTLIB static linking to eliminate MSVCR runtime dependencies",
    "String hashing seed randomized per build compilation",
    "UPX compression suppression to bypass static heuristic signatures"
  ],
  "operator_commands": [
    "PING: Verify C2 gate connectivity",
    "TASK_PULL: Retrieve dynamic file grabber rules",
    "CONFIG_UPDATE: Update secondary fallback gate URLs",
    "EXFIL_ACK: Acknowledge receipt of compressed credential archive",
    "TERMINATE: Signal client to execute self-deletion"
  ],
  "interface_telemetry_analysis": "The operator interface operates as a multi-tenant web application featuring live WebSocket feeds for incoming infection telemetry, automated sorting of high-value cryptocurrency assets, and structured log export routines."
}

struct Meduza_Stealer_Config {
    uint32_t magic;
    char c2_host[128];
    uint16_t port;
    char install_path[260];
    char mutex[64];
    uint8_t aes_key[32];
};

{
  "injection_chain": "Native standalone execution or reflective DLL injection: VirtualAlloc(PAGE_READWRITE) -> PE headers copy -> Section mapping -> Base relocation calculation -> Dynamic IAT resolution via manual Export Address Table (EAT) parsing -> VirtualProtect(PAGE_EXECUTE_READ) -> Execution handoff.",
  "ntapi_functions": [
    "ntdll!NtQueryInformationProcess",
    "ntdll!NtAllocateVirtualMemory",
    "ntdll!NtProtectVirtualMemory",
    "crypt32!CryptUnprotectData",
    "bcrypt!BCryptOpenAlgorithmProvider",
    "bcrypt!BCryptDecrypt",
    "wininet!InternetOpenW",
    "wininet!HttpSendRequestW"
  ],
  "process_hollowing_target": "Direct execution; when wrapped by crypter stagers, targets svchost.exe or explorer.exe",
  "persistence_mechanics": [
    "No native persistence routines implemented (ephemeral execution model)",
    "Self-terminating execution flow designed to harvest, exfiltrate, and immediately purge host footprint",
    "Self-deletion command executed via: cmd.exe /c timeout /t 3 & del /f /q \"%s\""
  ],
  "evasion_hooks": [
    "CIS Geofencing: Enumerates UI language via kernel32!GetUserDefaultUILanguage and keyboard layout via user32!GetKeyboardLayoutList; terminates if Russian (0x0419), Ukrainian (0x0422), Belarusian (0x0423), Kazakh (0x043F), Armenian (0x042B), or Azerbaijani (0x042C) are detected",
    "External IP validation: Queries ip-api.com or ipinfo.io; verifies country code against CIS exclusion list prior to executing grabber routines",
    "Debugger verification: Calls IsDebuggerPresent, CheckRemoteDebuggerPresent, and checks ProcessDebugPort via NtQueryInformationProcess"
  ],
  "anti_analysis": [
    "CPU Core Count Check: Queries GetSystemInfo; exits if dwNumberOfProcessors < 2",
    "Physical Memory Check: Queries GlobalMemoryStatusEx; terminates if total physical RAM < 4 GB",
    "Sandbox Module Inspection: Invokes GetModuleHandleA on sbiedll.dll, dbghelp.dll, and snxhk.dll to detect isolation sandboxes"
  ]
}

Concrete technical breakdown of functional modules implemented in the Meduza Stealer binary:

{
  "framing": "HTTPS POST request with multipart/form-data MIME boundary or raw application/octet-stream preceded by a 16-byte fixed header",
  "serialization": "In-memory ZIP archive containing structured files (passwords.txt, cookies.txt, autofill.txt, system_info.txt, Wallets/, Extensions/)",
  "handshake": "Client issues HTTPS POST /api/v1/check with HWID and build tag -> Server validates IP geolocation -> Server returns HTTP 200 OK -> Client uploads encrypted archive via POST /api/v1/gate -> Server returns 200 OK ACK -> Client terminates",
  "cryptography": "Payload compressed via in-memory Deflate algorithm; compressed buffer encrypted with RC4 stream cipher and enveloped in AES-256-CBC with prepended IV",
  "packet_types": [
    {
      "header": "POST /api/v1/check",
      "payload": "HWID, OS_Version, Build_ID, IP_Address",
      "direction": "Client -> Server"
    },
    {
      "header": "HTTP 200 OK (Check Response)",
      "payload": "Status: ACCEPT, GrabberRules: [...]",
      "direction": "Server -> Client"
    },
    {
      "header": "POST /api/v1/gate",
      "payload": "Encrypted ZIP archive payload buffer",
      "direction": "Client -> Server"
    },
    {
      "header": "HTTP 200 OK (Exfiltration Complete)",
      "payload": "Status: SUCCESS, Action: DIE",
      "direction": "Server -> Client"
    }
  ],
  "traffic_signature": "Outbound HTTPS traffic over port 443 with randomized user-agent strings masquerading as Chromium; content-length matches compressed archive buffer size."
}

Indicators of compromise and forensic patterns recorded across laboratory triage: