{
  "family": "crypt0l0cker",
  "sample_count": 2,
  "category": "ransomware",
  "description": "Ransomware:Win32/Crypt0l0cker is a highly destructive ransomware variant, often considered a direct clone or spiritual successor to the original, infamous CryptoLocker. It emerged around 2015 and specifically targeted Windows systems. Its primary objective is to encrypt user files using strong, unbreakable cryptography (typically AES-256 combined with RSA-2048) and demand payment, usually in Bitcoin, for the decryption key (`T1486`).<br><br><b>Understanding Crypt0l0cker</b><br>To an end-user, the infection is devastating: they suddenly find their documents, photos, and databases inaccessible, appended with random extensions, and a glaring ransom note (often `DECRYPT_INSTRUCTIONS.html` or `.txt`) displayed on the desktop. For a SOC, it represents a massive failure in preventative controls and necessitates immediate incident response to prevent lateral movement and further data loss.<br><br><b>Execution and Encryption Mechanics</b><br>Crypt0l0cker was primarily distributed via massive spam campaigns containing weaponized ZIP attachments, often leveraging botnets like Cutwail or using exploit kits (like Angler). Upon execution, it contacts a Command and Control (C2) server (often using Domain Generation Algorithms - DGA - to evade blocking) to obtain a unique public encryption key. It then scans all local drives and mapped network shares (`T1486`), encrypting files matching specific extensions (e.g., `.doc`, `.xls`, `.jpg`). Crucially, it attempts to delete Volume Shadow Copies (`vssadmin.exe Delete Shadows /All /Quiet`) to prevent easy restoration (`T1490`).<br><br><b>Indicators of Compromise & Impact</b><br>The impact is severe business disruption and data loss. Host-based IoCs include the presence of the ransom notes, files with altered extensions, execution of `vssadmin.exe` to delete shadow copies, and the malware establishing persistence via the `HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run` registry key. Network IoCs include outbound HTTP/HTTPS traffic to unknown, high-entropy domains (DGA) or known Tor exit nodes used for C2 communication.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Crypt0L0Cker and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Crypt0L0Cker 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 Crypt0L0Cker establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Crypt0L0Cker 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 Crypt0L0Cker compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Crypt0L0Cker 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 Crypt0L0Cker employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Crypt0L0Cker 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 Crypt0L0Cker, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Crypt0L0Cker 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": [
    "T1490",
    "T1566.001",
    "T1486",
    "T1568.002"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1486",
      "name": "Data Encrypted for Impact (The core ransomware functionality)",
      "tactic": "Impact"
    },
    {
      "id": "T1490",
      "name": "Inhibit System Recovery (Deleting Volume Shadow Copies)",
      "tactic": "Impact"
    },
    {
      "id": "T1566.001",
      "name": "Phishing: Spearphishing Attachment (Primary delivery mechanism via malspam)",
      "tactic": "Initial Access"
    },
    {
      "id": "T1568.002",
      "name": "Dynamic Resolution: Domain Generation Algorithms (Using DGA for C2 resilience)",
      "tactic": "Command and Control"
    }
  ],
  "containment_steps": [
    "Isolate the infected endpoint and IMMEDIATELY disconnect it from all network shares to prevent the ransomware from encrypting shared company drives.",
    "Do NOT turn off the machine immediately if possible; capture a live memory image, as the encryption keys might temporarily reside in RAM.",
    "Identify the entry vector (e.g., malicious email attachment) and purge it from the corporate email system to prevent further infections.",
    "Restore affected data from offline, immutable backups. Ensure the backups themselves were not compromised."
  ],
  "what_to_avoid": [
    "Do not pay the ransom unless absolutely necessary (e.g., life safety data); paying funds organized crime and does not guarantee data recovery.",
    "Avoid reconnecting the machine to the network until it has been completely wiped and the OS reinstalled from scratch."
  ],
  "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"
  ]
}