{
  "family": "snow",
  "sample_count": 1,
  "category": "ransomware",
  "description": "<h3>Executive Summary</h3>\nSnow (often associated with the Snow Ransomware family or a specific Trojan downloader) is a malicious threat designed to infiltrate Windows systems, establish persistence, and execute destructive payloads. When operating as ransomware, Snow utilizes strong encryption algorithms to lock down the victim's critical data, demanding a ransom payment in exchange for the decryption key, causing immediate and severe operational downtime.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nSnow is predominantly distributed via targeted phishing campaigns containing weaponized attachments, or by exploiting weak Remote Desktop Protocol (RDP) credentials exposed to the public internet.\n\nUpon successful execution, the malware operates with a focus on speed and destruction:\n<ul>\n<li><strong>Defense Evasion:</strong> Snow typically attempts to disable local Windows Defender services and terminate processes associated with enterprise backup solutions and database servers (e.g., SQL Server, Exchange) to ensure all data files are unlocked and ready for encryption.</li>\n<li><strong>Rapid File Encryption:</strong> The ransomware scans local drives and mapped network shares, targeting specific file extensions (documents, databases, archives). It encrypts these files using a strong cryptographic algorithm (often AES/RSA hybrid) and appends a specific extension (like `.snow`) to the encrypted files.</li>\n<li><strong>Shadow Copy Deletion:</strong> To prevent easy recovery, Snow almost universally executes commands (like `vssadmin.exe delete shadows /all /quiet`) to instantly destroy Windows Volume Shadow Copies and disable local backup routines.</li>\n<li><strong>Extortion:</strong> After the encryption phase is complete, it drops a ransom note outlining the payment instructions (usually in cryptocurrency) and threatening permanent data loss.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nA Snow ransomware infection is a catastrophic security incident resulting in immediate, severe operational downtime and massive data loss. Due to the strength of modern encryption, files cannot be recovered without the private key or a viable offline backup.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>Immediate Physical Isolation:</strong> Disconnect the infected machine from the network immediately (pull the Ethernet cable/disable Wi-Fi) to halt the encryption process and prevent the ransomware from traversing SMB shares to encrypt centralized file servers.</li>\n<li><strong>Do Not Reboot:</strong> Leave the machine powered on. Rebooting may trigger further destructive routines or destroy the encryption key if it temporarily resides in RAM.</li>\n<li><strong>Restore from Offline Backups:</strong> The only reliable remediation is to completely wipe the infected system (bare-metal reinstall) and restore the data from secure, offline backups that were unreachable by the ransomware.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Ransomware.Snow",
    "Trojan-Ransom.Win32.Snow",
    "Filecoder.Snow"
  ],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Snow and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Snow is classified as a Ransomware. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments."
      }
    },
    {
      "@type": "Question",
      "name": "How does Snow establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Snow typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks."
      }
    },
    {
      "@type": "Question",
      "name": "What are the essential incident response steps for mitigating a Snow compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Snow should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups."
      }
    },
    {
      "@type": "Question",
      "name": "What cryptographic algorithms and file targeting techniques does Ransomware.Snow employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Ransomware.Snow typically leverages hybrid cryptographic architectures combining symmetric stream or block ciphers (such as AES-256 or ChaCha20) for rapid file encryption with asymmetric algorithms (such as RSA-2048 or Curve25519) to securely protect the session keys. It aggressively targets sensitive file extensions including corporate documents, databases, virtual disks, and backups while systematically executing commands to delete Volume Shadow Copies (vssadmin delete shadows /all /quiet) and disable system recovery options."
      }
    },
    {
      "@type": "Question",
      "name": "Are decryptors available for Ransomware.Snow, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Ransomware.Snow depends on whether security researchers or law enforcement (such as the No More Ransom initiative) have recovered the master private keys or discovered flaws in its key generation routines. Victims should never pay the extortion demand, as payment fuels criminal operations without guaranteeing file restoration. The recommended recovery procedure entails isolating infected hosts, conducting forensic disk imaging, identifying the root access vector, and restoring validated systems from immutable offline backups."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1486",
    "T1490",
    "T1566.001",
    "T1059"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "type": "Ransomware / Trojan",
  "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,
  "mitre_attack_detail": [
    {
      "id": "T1486",
      "name": "Data Encrypted for Impact",
      "tactic": "Impact"
    },
    {
      "id": "T1490",
      "name": "Inhibit System Recovery (Behaviorally blocking the deletion of backups)",
      "tactic": "Impact"
    },
    {
      "id": "T1566.001",
      "name": "Phishing: Spearphishing Attachment",
      "tactic": "Initial Access"
    },
    {
      "id": "T1059",
      "name": "Command and Scripting Interpreter",
      "tactic": "Execution"
    }
  ],
  "containment_steps": [
    "Immediately isolate affected host(s) from the internal network (disconnect physical Ethernet and disable Wi-Fi/Bluetooth) to prevent Snow from spreading laterally or encrypting network-attached storage (NAS) and shared SMB volumes.",
    "Preserve volatile system memory (RAM capture) on a representative endpoint before attempting a reboot or power-down, as Snow symmetric encryption keys or uncompiled payload components may still reside in memory.",
    "Audit process execution logs and terminate active scripting interpreters (e.g. PowerShell, CMD, WScript) or commands executing 'vssadmin.exe delete shadows' or 'wbadmin' used by Snow to inhibit recovery.",
    "Investigate the initial compromise vector (such as exposed RDP instances, spearphishing attachments, or vulnerable edge gateways) and enforce an immediate credential reset for all compromised Active Directory accounts.",
    "Restore critical assets and databases exclusively from verified, air-gapped, or immutable offline backups once the Snow binary and related persistence hooks are eradicated."
  ],
  "what_to_avoid": [
    "Do not restart or power cycle infected systems prematurely; doing so destroys volatile RAM encryption keys and may trigger bootloader locking logic embedded in Snow.",
    "Avoid negotiating or paying the extortion demand without prior forensic evaluation and consultation with incident response specialists, as payment does not guarantee data recovery.",
    "Do not connect clean backup drives or external storage to the affected network until Snow eradication is completely verified."
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows Server 2022",
    "Windows Server 2019"
  ]
}