{
  "family": "cryptojoker",
  "sample_count": 1,
  "category": "ransomware",
  "description": "<h3>Executive Summary</h3>\nCryptoJoker is a highly destructive strain of file-encrypting Ransomware. It is designed to quickly infiltrate a system, encrypt all valuable user data (documents, databases, images) using strong cryptographic algorithms, and demand a cryptocurrency payment (usually Bitcoin) in exchange for the decryption key. It poses an immediate, catastrophic threat to business continuity and data availability.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nCryptoJoker is typically distributed through massive, automated malspam campaigns containing malicious attachments, via drive-by downloads from compromised websites (Exploit Kits), or directly deployed by attackers who have purchased access to the network from Initial Access Brokers (often via compromised RDP endpoints).\n\nUpon execution, CryptoJoker performs a rapid, highly visible attack:\n<ul>\n<li><strong>VSS Deletion and Backup Destruction:</strong> The ransomware's first action is to execute commands (e.g., `vssadmin.exe Delete Shadows /All /Quiet`) to delete Volume Shadow Copies and disable Windows Recovery, preventing the user from easily restoring the encrypted files.</li>\n<li><strong>Rapid Encryption:</strong> It scans local drives and mapped network shares for specific file extensions. It typically uses a combination of AES for fast file encryption and RSA to secure the AES keys. Encrypted files are often appended with a specific extension (e.g., `.joker` or `.crpt`).</li>\n<li><strong>Extortion and Ransom Note:</strong> Once encryption is complete, the malware drops a ransom note (usually a `.txt` or `.html` file) in every affected directory and changes the desktop wallpaper. The note provides instructions on how to access a Tor-hosted payment portal to purchase the decryption tool.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nA CryptoJoker infection is a critical, tier-one security incident. It results in an immediate loss of data availability and severe operational disruption. Furthermore, many modern ransomware operations employ \"double extortion,\" meaning they exfiltrate sensitive data *before* encrypting the network, threatening to leak it publicly if the ransom is not paid.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>Immediate Network Severance:</strong> The absolute highest priority is to physically sever the infected endpoint (and any servers it can reach) from the network to halt the spread of the encryption across mapped drives and prevent data exfiltration.</li>\n<li><strong>DO NOT REBOOT:</strong> Do not reboot the infected machine. Rebooting can trigger \"wiper\" routines in some ransomware variants or clear volatile memory (RAM) that might contain the encryption key.</li>\n<li><strong>Restore from Offline Backups:</strong> Paying the ransom is strongly discouraged, as it funds criminal enterprises and does not guarantee data recovery. Eradication requires a complete bare-metal wipe of the infected infrastructure and a full restoration from secure, offline (air-gapped) backups.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Ransom.CryptoJoker",
    "Trojan-Ransom.Win32.CryptoJoker",
    "Win32/Filecoder.CryptoJoker"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1486",
    "T1490",
    "T1012"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-02T06:52:06Z",
  "type": "Ransomware",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}