{
  "metadata": {
    "report_title": "full_test_enc.exe (Arsenal-237) IOC Feed",
    "report_date": "2026-01-27",
    "malware_family": "Arsenal-237 Toolkit",
    "malware_type": "Ransomware",
    "threat_level": "CRITICAL",
    "confidence_level": "HIGH (95%)",
    "hash_confidence": "CONFIRMED",
    "behavioral_confidence": "CONFIRMED"
  },
  "file_hashes": {
    "md5": [
      {
        "hash": "1fe8b9a14f9f8435c5fb5156bcbc174e",
        "filename": "full_test_enc.exe",
        "file_size": "15565824",
        "file_type": "PE32+ (64-bit Windows executable)",
        "confidence": "CONFIRMED"
      }
    ],
    "sha1": [
      {
        "hash": "bc0788a36b6b839fc917be0577cd14e584c71fd8",
        "filename": "full_test_enc.exe",
        "confidence": "CONFIRMED"
      }
    ],
    "sha256": [
      {
        "hash": "4d1fe7b54a0ce9ce2082c167b662ec138b890e3f305e67bdc13a5e9a24708518",
        "filename": "full_test_enc.exe",
        "confidence": "CONFIRMED"
      }
    ]
  },
  "network_indicators": {
    "ips": [],
    "domains": [],
    "urls": [],
    "note": "Offline ransomware - no C2 communication infrastructure identified"
  },
  "host_indicators": {
    "registry_keys": [
      {
        "hive": "HKEY_LOCAL_MACHINE",
        "path": "Software\\Microsoft\\Windows\\Run",
        "note": "Monitor for malware registry persistence"
      },
      {
        "hive": "HKEY_CURRENT_USER",
        "path": "Software\\Microsoft\\Windows\\Run",
        "note": "Monitor for malware registry persistence"
      }
    ],
    "file_paths": [
      {
        "path": "C:\\Windows\\Temp",
        "note": "Hardcoded folder option string in malware"
      }
    ],
    "mutex_names": [],
    "service_names": [],
    "file_extensions": [
      {
        "extension": ".lockbox",
        "description": "Encrypted file indicator - appended to encrypted files",
        "confidence": "CONFIRMED"
      }
    ]
  },
  "behavioral_indicators": {
    "process_creation": [
      {
        "process": "full_test_enc.exe",
        "parent": "Any (user execution)",
        "indicator": "Unsigned 15+ MB Rust executable",
        "confidence": "HIGH"
      }
    ],
    "command_execution": [
      {
        "command": "net use",
        "source": "full_test_enc.exe or unsigned binary",
        "purpose": "Network share enumeration",
        "indicator": "Unsigned binary executing network enumeration",
        "confidence": "CONFIRMED"
      }
    ],
    "file_operations": [
      {
        "operation": "Mass file creation",
        "indicator": "10+ files with .lockbox extension created in <1 minute",
        "confidence": "CONFIRMED",
        "severity": "CRITICAL"
      },
      {
        "operation": "File deletion",
        "indicator": "Original file deleted immediately after encryption",
        "pattern": "File creation → File modification → File deletion → .lockbox creation",
        "confidence": "DEFINITE"
      },
      {
        "operation": "Parallel WriteFile calls",
        "indicator": "4-16+ simultaneous file write operations (CPU core count)",
        "confidence": "HIGH",
        "detection_tool": "EDR process monitoring"
      }
    ],
    "api_calls": [
      {
        "api": "GetLogicalDrives",
        "purpose": "Enumerate all mounted drives (A-Z)",
        "confidence": "CONFIRMED"
      },
      {
        "api": "CreateProcessW",
        "purpose": "Execute 'net use' for network share discovery",
        "confidence": "CONFIRMED"
      },
      {
        "api": "AddVectoredExceptionHandler",
        "purpose": "Anti-analysis/debugging evasion",
        "confidence": "CONFIRMED"
      },
      {
        "api": "SetUnhandledExceptionFilter",
        "purpose": "Anti-analysis/debugging evasion",
        "confidence": "CONFIRMED"
      }
    ]
  },
  "string_indicators": {
    "ransom_strings": [
      {
        "string": "YOUR FILES HAVE BEEN ENCRYPTED!",
        "type": "Ransom message",
        "confidence": "CONFIRMED",
        "severity": "CRITICAL"
      },
      {
        "string": "Ransom ID:",
        "type": "Victim identifier",
        "confidence": "CONFIRMED"
      }
    ],
    "behavioral_strings": [
      {
        "string": "[*] Encryptor starting...",
        "type": "Debug/operational logging",
        "confidence": "CONFIRMED",
        "note": "Indicates development/test build"
      },
      {
        "string": "[*] Encrypting all drives...",
        "type": "Operational logging",
        "confidence": "CONFIRMED"
      },
      {
        "string": "[*] Full encryption mode",
        "type": "Operational logging",
        "confidence": "CONFIRMED"
      },
      {
        "string": "[+] Encrypted ",
        "type": "Progress logging",
        "confidence": "CONFIRMED"
      },
      {
        "string": "[+] Encryption complete!",
        "type": "Completion logging",
        "confidence": "CONFIRMED"
      },
      {
        "string": "[+] GUI launched!",
        "type": "UI launch logging",
        "confidence": "CONFIRMED"
      },
      {
        "string": "RUST_UI",
        "type": "UI mode indicator",
        "confidence": "CONFIRMED"
      },
      {
        "string": "Failed to execute net use",
        "type": "Error message",
        "confidence": "CONFIRMED"
      },
      {
        "string": "[-] Invalid folder:",
        "type": "Error message",
        "confidence": "CONFIRMED"
      },
      {
        "string": "Failed to encrypt nonce",
        "type": "Encryption error",
        "confidence": "CONFIRMED",
        "note": "Indicates ChaCha20 nonce generation issue"
      },
      {
        "string": "Failed to encrypt key",
        "type": "Encryption error",
        "confidence": "CONFIRMED",
        "note": "Indicates RSA key encryption issue"
      },
      {
        "string": "Block encryption failed",
        "type": "Encryption error",
        "confidence": "CONFIRMED"
      }
    ],
    "cryptographic_library_paths": [
      {
        "path": "/chacha20-0.9.1/src/lib.rs",
        "library": "ChaCha20 stream cipher",
        "purpose": "Fast file encryption",
        "confidence": "CONFIRMED",
        "note": "Professional cryptographic implementation"
      },
      {
        "path": "/rsa-0.9.9/src/algorithms/",
        "library": "RSA asymmetric encryption",
        "purpose": "Secure key distribution (OAEP padding)",
        "confidence": "CONFIRMED",
        "note": "High-security key encapsulation"
      },
      {
        "path": "/aead-0.5.2/src/lib.rs",
        "library": "Authenticated Encryption with Associated Data",
        "purpose": "Encryption integrity verification",
        "confidence": "CONFIRMED"
      },
      {
        "path": "/cipher-0.4.4/",
        "library": "Generic cipher traits",
        "purpose": "Cipher abstraction layer",
        "confidence": "CONFIRMED"
      },
      {
        "path": "/digest-0.10.7/",
        "library": "Cryptographic hash functions",
        "purpose": "Key derivation and authentication",
        "confidence": "CONFIRMED"
      },
      {
        "path": "/rand-0.8.5/",
        "library": "Cryptographically secure random number generation",
        "purpose": "Key and nonce generation",
        "confidence": "CONFIRMED"
      }
    ],
    "performance_library_paths": [
      {
        "path": "/rayon-1.11.0/src/",
        "library": "Parallel processing",
        "purpose": "Multi-threaded encryption across CPU cores",
        "confidence": "CONFIRMED",
        "impact": "Enables enterprise-wide encryption in minutes"
      },
      {
        "path": "/rayon-core-1.13.0/",
        "library": "Thread pool management",
        "purpose": "Efficient work distribution",
        "confidence": "CONFIRMED"
      },
      {
        "path": "/sysinfo-0.29.11/",
        "library": "System information collection",
        "purpose": "Query CPU cores for thread pool sizing",
        "confidence": "CONFIRMED"
      },
      {
        "path": "/walkdir-2.5.0/",
        "library": "Recursive directory traversal",
        "purpose": "Efficient file enumeration",
        "confidence": "CONFIRMED"
      }
    ]
  },
  "mitre_attack_mapping": {
    "techniques": [
      {
        "tactic": "Execution",
        "technique": "T1204.002",
        "name": "User Execution: Malicious File",
        "confidence": "HIGH",
        "evidence": "PE executable requires user or automated execution"
      },
      {
        "tactic": "Defense Evasion",
        "technique": "T1622",
        "name": "Debugger Evasion",
        "confidence": "CONFIRMED",
        "evidence": "Vectored exception handlers, SetUnhandledExceptionFilter API"
      },
      {
        "tactic": "Defense Evasion",
        "technique": "T1497.001",
        "name": "Virtualization/Sandbox Evasion",
        "confidence": "CONFIRMED",
        "evidence": "YARA detections: VMware_Detection, VirtualBox_Detection"
      },
      {
        "tactic": "Defense Evasion",
        "technique": "T1027",
        "name": "Obfuscated Files or Information",
        "confidence": "MODERATE",
        "evidence": "Large Rust binary with static linking obscures analysis"
      },
      {
        "tactic": "Discovery",
        "technique": "T1082",
        "name": "System Information Discovery",
        "confidence": "HIGH",
        "evidence": "sysinfo library (CPU, disk, network enumeration modules)"
      },
      {
        "tactic": "Discovery",
        "technique": "T1083",
        "name": "File and Directory Discovery",
        "confidence": "CONFIRMED",
        "evidence": "WalkDir library, GetLogicalDrives, directory navigation APIs"
      },
      {
        "tactic": "Discovery",
        "technique": "T1135",
        "name": "Network Share Discovery",
        "confidence": "CONFIRMED",
        "evidence": "'net use' command execution, UNC path handling"
      },
      {
        "tactic": "Lateral Movement",
        "technique": "T1021.002",
        "name": "Remote Services: SMB/Windows Admin Shares",
        "confidence": "HIGH",
        "evidence": "Network share encryption via 'net use', UNC support"
      },
      {
        "tactic": "Impact",
        "technique": "T1486",
        "name": "Data Encrypted for Impact",
        "confidence": "CONFIRMED",
        "evidence": "ChaCha20 + RSA encryption, .lockbox extension, ransom strings"
      }
    ]
  },
  "toolkit_context": {
    "family": "Arsenal-237",
    "components": [
      {
        "name": "full_test_enc.exe",
        "type": "Encryption module",
        "status": "Test/Development build",
        "deployment_status": "Not yet widely deployed",
        "severity": "CRITICAL"
      }
    ],
    "relationship_to_blackcat": {
      "assessment": "INSPIRED BY (NOT derivative)",
      "confidence": "MODERATE (70%)",
      "similarities": [
        "Rust programming language",
        "ChaCha20 stream cipher",
        "Rayon multi-threading",
        "Network share targeting",
        "Professional implementation"
      ],
      "differences": [
        "No C2 infrastructure (BlackCat has robust C2)",
        "No data exfiltration (BlackCat does double extortion)",
        "Standalone vs. RaaS deployment model",
        "Different file extension (.lockbox vs. variable)",
        "Test build vs. production-mature"
      ]
    }
  },
  "detection_evasion": {
    "anti_analysis_techniques": [
      {
        "technique": "VM Detection",
        "method": "CPUID, registry checks, VMware/VirtualBox driver detection",
        "effectiveness": "HIGH - prevents sandbox analysis",
        "bypasses": "Advanced hypervisor detection, physical hardware analysis"
      },
      {
        "technique": "Debugger Evasion",
        "method": "Vectored exception handlers, BeingDebugged flag",
        "effectiveness": "HIGH - prevents step-through debugging",
        "bypasses": "Kernel-mode debugging, memory forensics, static analysis"
      },
      {
        "technique": "Exception Handling",
        "method": "Custom SEH, exception handler hijacking",
        "effectiveness": "MEDIUM - complicates dynamic analysis",
        "bypasses": "Kernel debugging, memory dumps, behavioral monitoring"
      }
    ],
    "what_evasion_cannot_prevent": [
      "YARA scanning (pattern matching)",
      "Memory forensics (memory dump analysis)",
      "EDR behavioral detection (process telemetry)",
      "Static analysis (disassembly)",
      "File system monitoring (encryption indicators)",
      "Network monitoring (lateral movement detection)"
    ]
  },
  "threat_assessment": {
    "overall_risk_score": "9.5/10",
    "risk_rating": "CRITICAL",
    "risk_components": {
      "encryption_irreversibility": {
        "score": "10/10",
        "factor": "Critical",
        "justification": "RSA-OAEP + ChaCha20 is cryptographically sound; no decryption possible without private key"
      },
      "speed_of_execution": {
        "score": "9.5/10",
        "factor": "Critical",
        "justification": "Multi-threaded parallel processing encrypts enterprise network in 30-60 minutes"
      },
      "scope_of_impact": {
        "score": "9.5/10",
        "factor": "Critical",
        "justification": "Targets all drives (A-Z) plus network shares; single infection spreads organization-wide"
      },
      "detection_difficulty": {
        "score": "8/10",
        "factor": "High",
        "justification": "VM/debugger detection and offline operation bypass network defenses"
      },
      "lateral_movement": {
        "score": "8/10",
        "factor": "High",
        "justification": "Network share enumeration enables domain-wide lateral movement"
      },
      "recovery_complexity": {
        "score": "10/10",
        "factor": "Critical",
        "justification": "Only option is rebuild from clean backups; no recovery tool exists"
      }
    },
    "threat_timeline": {
      "0_to_5_minutes": "Initial encryption burst completes (user files encrypted)",
      "5_to_15_minutes": "Lateral movement to network shares begins (if accessible)",
      "15_to_30_minutes": "Significant portion of file server data encrypted",
      "30_to_60_minutes": "Enterprise-wide compromise for typical mid-size organization"
    },
    "detection_window": "CRITICAL - Detection must occur within first 15 minutes to contain spread"
  },
  "recovery_options": {
    "viable_recovery": "Backup restoration ONLY",
    "impossible_recovery": [
      "Brute-force encryption (would require 6400+ years)",
      "Break RSA cryptography (no known mathematical weakness)",
      "Ransomware decryptor (no private key available)",
      "Ransomware negotiation (no guarantee of key release)"
    ],
    "backup_requirements": {
      "must_be_isolated": "Ransomware cannot access backup systems",
      "must_be_clean": "Backup must not contain encrypted files",
      "must_be_tested": "Restoration should be tested before relying on recovery"
    }
  },
  "recommendations": {
    "immediate": [
      "Search environment for all hash values (MD5, SHA1, SHA256)",
      "Alert on .lockbox file extension creation events",
      "Monitor for 15+ MB unsigned binaries executing",
      "Implement EDR with behavioral ransomware detection"
    ],
    "short_term": [
      "Deploy EDR to all endpoints",
      "Create SIEM alerts for mass file encryption patterns",
      "Implement network segmentation between user and file server networks",
      "Verify backup system isolation and integrity"
    ],
    "medium_term": [
      "Application whitelisting/control implementation",
      "Network segmentation enforcement",
      "Immutable backup implementation",
      "Security awareness training"
    ],
    "long_term": [
      "EDR enterprise-wide deployment",
      "Process improvement and automation",
      "Incident response capability enhancement",
      "Continuous threat hunting program"
    ]
  }
}