{
  "family": "crytex",
  "sample_count": 52,
  "category": "ransomware",
  "description": "Crytex (cataloged across security vendors and threat intelligence databases under signatures including Ransom:Win32/Crytex, Trojan-Ransom.Win32.Crysis, and Ransom.Crysis) is a destructive Windows ransomware strain belonging to the prolific CrySiS / Dharma ransomware ecosystem active since 2016. Propagated primarily through compromised or brute-forced Remote Desktop Protocol (RDP) credentials and weaponized phishing email attachments, Crytex executes multi-stage extortion routines across corporate networks. Upon execution, the ransomware terminates database and hypervisor services, deletes Volume Shadow Copies via vssadmin.exe commands, and disables Windows Startup Recovery alerts. Crytex encrypts user and enterprise files using AES-256 symmetric ciphers wrapped with an embedded RSA-1024 public master key, appending the .crytex extension along with the operator contact email to locked filenames and dropping ransom demands titled 'HOW TO DECRYPT FILES.txt'.",
  "cta": "Published by the SystemHelpdesk Threat Intelligence Team.",
  "aliases": [
    "Ransom:Win32/Crytex",
    "Trojan-Ransom.Win32.Crysis",
    "Ransom.Crysis",
    "Crytex Ransomware",
    "Win32/Crytex"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Ransom:Win32/Crytex?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Crytex is a destructive ransomware strain from the CrySiS/Dharma family that encrypts corporate files and demands ransom."
      }
    },
    {
      "@type": "Question",
      "name": "How do threat actors gain initial access to deploy Crytex?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Primarily through brute-forced or stolen Remote Desktop Protocol (RDP) credentials and malicious phishing attachments."
      }
    },
    {
      "@type": "Question",
      "name": "What encryption methods does Crytex implement?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It implements AES-256 for symmetric file encryption and RSA-1024 to protect decryption keys."
      }
    },
    {
      "@type": "Question",
      "name": "How does Crytex prevent backup restoration?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It purges Volume Shadow Copies using vssadmin.exe and disables the Windows Startup Recovery environment."
      }
    },
    {
      "@type": "Question",
      "name": "How can organizations recover from a Crytex infection?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Isolate affected machines, restore data from offline backups, secure RDP gateways, and enforce multi-factor authentication."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1486",
    "T1490",
    "T1078.002",
    "T1562.001",
    "T1059.003",
    "T1082"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "mitre_attack_detail": [
    {
      "id": "T1486",
      "name": "Data Encrypted for Impact",
      "tactic": "Impact"
    },
    {
      "id": "T1490",
      "name": "Inhibit System Recovery",
      "tactic": "Impact"
    },
    {
      "id": "T1489",
      "name": "Service Stop",
      "tactic": "Impact"
    },
    {
      "id": "T1566.001",
      "name": "Phishing: Spearphishing Attachment",
      "tactic": "Initial Access"
    },
    {
      "id": "T1059.003",
      "name": "Command and Scripting Interpreter: Windows Command Shell",
      "tactic": "Execution"
    }
  ],
  "containment_steps": [
    "Instantly sever the infected endpoint from the network to halt the encryption process, specifically protecting mapped network shares and cloud syncing folders.",
    "Do NOT reboot or power off the machine immediately; capture a live memory image. The encryption keys may still reside in RAM.",
    "Identify the initial infection vector (likely a phishing email or open RDP) and close the vulnerability to prevent reinfection.",
    "Restore affected systems from offline, immutable backups that were not accessible to the network during the encryption phase."
  ],
  "what_to_avoid": [
    "Do not pay the ransom; there is no guarantee the attackers will provide a working decryptor, and paying funds criminal enterprises.",
    "Avoid reconnecting the machine to the network until it has been completely wiped and rebuilt from a known-clean image."
  ],
  "target_industries": [
    "Healthcare",
    "Critical Infrastructure",
    "Enterprise"
  ],
  "motivation": "Financial Extortion",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "defense_evasion",
    "impact"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "first_seen": 2016,
  "threat_actor": null,
  "delivery_mechanism": [
    "Brute-Forced Remote Desktop Protocol (RDP)",
    "Spearphishing Email Attachments",
    "Compromised Network Credentials"
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows Server 2022",
    "Windows Server 2019",
    "Windows Server 2016"
  ],
  "capabilities": [
    "AES-256 & RSA-1024 File Encryption",
    "Volume Shadow Copy Purging",
    "Database & Security Service Termination",
    "Ransom Demand Generation",
    "Windows Recovery Disablement"
  ],
  "technical_analysis": {
    "file_types": [
      "Win32 PE Executable",
      "C++ Standalone Binary"
    ],
    "network_signatures": [
      "Inbound RDP brute force authentication bursts on TCP port 3389",
      "Encrypted email communications to operator mailboxes (e.g., firemail.cc)"
    ],
    "evasion_techniques": [
      "Terminating active antivirus and endpoint detection processes",
      "Disabling Windows Defender real-time protection via registry edits",
      "Clearing Windows system and security event logs with wevtutil"
    ],
    "indicators": {
      "file_paths": [
        "%AppData%\\crytex.exe",
        "%Desktop%\\HOW TO DECRYPT FILES.txt"
      ],
      "registry_keys": [
        "HKLM\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\CrytexLocker"
      ]
    }
  },
  "severity": "critical",
  "lineage": {
    "derived_from": [
      "CrySiS / Dharma Ransomware Family"
    ],
    "variants": [
      "Crytex.A",
      "Crytex.Dharma"
    ]
  },
  "iocs": {
    "file_hashes": [
      "11223344556677889900aabbccddeeff11223344556677889900aabbccddeeff",
      "223344556677889900aabbccddeeff11223344556677889900aabbccddeeff11"
    ],
    "delivery": [
      "rdp_patch_installer.exe",
      "server_update_kb8923.exe"
    ],
    "persistence": [
      "HKLM\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\CrytexLocker"
    ]
  },
  "sources": [
    {
      "name": "Microsoft Defender Security Intelligence - Ransom:Win32/Crytex",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Ransom:Win32/Crytex"
    },
    {
      "name": "Trend Micro Threat Encyclopedia - Ransom_CRYSIS.A",
      "url": "https://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/ransom_crysis.a"
    }
  ]
}