{
  "family": "cryptomix",
  "sample_count": 1,
  "category": "ransomware",
  "description": "Ransomware:Win32/Cryptomix is a well-known, historically significant ransomware family. Its primary objective is to encrypt the victim's files using strong cryptographic algorithms (typically RSA-2048 and AES-256) (`T1486`) and extort cryptocurrency. Cryptomix is notable for its numerous variants (like Cryptoshield), its shifting network of payment portals hosted on the Tor network, and its aggressive deletion of system recovery options.<br><br><b>Understanding Cryptomix (Ransomware)</b><br>To an end-user, a Cryptomix infection is devastating. They will suddenly find their documents, photos, and databases inaccessible, appended with an extension (which varied heavily between versions, e.g., `.scl`, `.code`, `.rmp`), accompanied by a stark 'Ransom Note' providing instructions to pay the attackers via Bitcoin. For an organization, it represents a critical incident requiring immediate network isolation.<br><br><b>Execution and Encryption Mechanics</b><br>Cryptomix was typically delivered via exploit kits (like RIG or GrandSoft) or via malicious spam attachments. Upon execution, it immediately executes commands to delete Volume Shadow Copies (`vssadmin.exe delete shadows`) (`T1490`) and disable the Windows Startup Repair feature to prevent easy data recovery. It then rapidly traverses local drives and mapped network shares (`T1012`), encrypting files. A unique feature of early Cryptomix was its reliance on a hardcoded list of public keys; if it couldn't reach its C2 server, it would use an 'offline' key, which security researchers were sometimes able to extract to build free decryptors.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is the total loss of data availability. Host-based IoCs include the sudden renaming of thousands of files, the presence of ransom notes (e.g., `HELP_INSTRUCTION.txt`), and EDR alerts for rapid file modification operations. System logs will show the execution of commands designed to inhibit system recovery (`vssadmin`, `bcdedit`). Network IoCs include DNS requests to known Cryptomix C2 infrastructure, often routing through compromised websites.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Cryptomix and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Cryptomix 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 Cryptomix establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Cryptomix 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 Cryptomix compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Cryptomix 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 Cryptomix employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Cryptomix 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 Cryptomix, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Cryptomix 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",
    "T1012",
    "T1490"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1486",
      "name": "Data Encrypted for Impact (The core function of encrypting the victim's data)",
      "tactic": "Impact"
    },
    {
      "id": "T1490",
      "name": "Inhibit System Recovery (Deleting Shadow Copies and disabling Windows repair)",
      "tactic": "Impact"
    },
    {
      "id": "T1012",
      "name": "Query Registry (Identifying mounted drives and network shares to encrypt)",
      "tactic": "Discovery"
    }
  ],
  "containment_steps": [
    "Isolate the infected machine from the network immediately to stop the encryption process from spreading to mapped network shares.",
    "Do not reboot the machine; if the encryption process is active, rebooting may finalize the damage or destroy volatile memory keys.",
    "Check resources like 'No More Ransom' to see if a free decryptor exists for the specific variant of Cryptomix you are facing.",
    "Restore operations from known-good, offline backups; paying the ransom is highly discouraged and funds criminal enterprises."
  ],
  "what_to_avoid": [
    "Do not connect backup drives to the infected machine until it has been completely wiped and reimaged.",
    "Avoid paying the ransom unless absolutely critical for human safety, as Cryptomix operators were known for poor customer service and failing to deliver decryptors."
  ],
  "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,
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows Server 2022",
    "Windows Server 2019"
  ]
}