{
  "family": "cryakl",
  "sample_count": 8,
  "category": "ransomware",
  "description": "Ransom:Win32/Cryakl is a highly destructive, Russian-origin ransomware family first observed around 2014. It is designed to aggressively encrypt a wide range of user documents, databases, and media files, appending a distinct extension (often containing an email address or random characters) to the encrypted files, and demanding a cryptocurrency ransom for the decryption key. It is known for its robust encryption algorithms and targeted attacks against enterprises.<br><br><b>Understanding Cryakl Ransomware</b><br>To a victim, a Cryakl infection is an immediate disaster; their desktop background is changed to a ransom note, and all crucial files are rendered inaccessible. For a security analyst, responding to Cryakl requires immediate, drastic containment. The malware utilizes a combination of RSA and AES encryption, meaning files cannot be brute-forced or decrypted without the attacker's private key. Cryakl also specifically targets network shares, amplifying the damage across the organization.<br><br><b>Execution and Encryption Mechanics</b><br>Cryakl is commonly distributed via malicious spam campaigns (`T1566.001`) containing weaponized ZIP attachments (often disguised as invoices or legal documents) or via RDP brute-forcing (`T1110`). Upon execution (`T1204.002`), it attempts to escalate privileges (`T1068`). Once running, it utilizes the `vssadmin.exe` utility to delete all Volume Shadow Copies (`T1490`), preventing easy system restoration. It then traverses all local drives and mapped network shares, searching for specific file extensions (e.g., .doc, .xls, .jpg, .sql). It encrypts these files using strong cryptography (`T1486`), renames them, and drops a ransom note (usually a `.txt` or `.html` file) in every affected directory. Cryakl often communicates with a C2 server to transmit the unique victim ID and encryption keys (`T1041`).<br><br><b>Indicators of Compromise & Impact</b><br>The impact is total data loss and massive operational disruption. The most obvious IoC is the sudden renaming of thousands of files to include a specific, anomalous extension (e.g., `.cryakl`, `.fair`) and the presence of the ransom note. EDR logs will flag the execution of `vssadmin.exe delete shadows /all /quiet`. Network analysts may observe a brief burst of outbound traffic as the malware transmits the encryption keys to the C2 server.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Cryakl and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Cryakl 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 Cryakl establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Cryakl 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 Cryakl compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Cryakl 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 Cryakl employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Cryakl 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 Cryakl, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Cryakl 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",
    "T1110",
    "T1204.002",
    "T1490"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1486",
      "name": "Data Encrypted for Impact",
      "tactic": "Impact"
    },
    {
      "id": "T1490",
      "name": "Inhibit System Recovery (Deleting Shadow Copies via vssadmin)",
      "tactic": "Impact"
    },
    {
      "id": "T1204.002",
      "name": "User Execution: Malicious File",
      "tactic": "Execution"
    },
    {
      "id": "T1110",
      "name": "Brute Force (RDP Initial Access)",
      "tactic": "Credential Access"
    }
  ],
  "containment_steps": [
    "Instantly isolate the infected endpoint from the network by physically unplugging the ethernet cable or disabling the switch port to halt the encryption of network shares.",
    "Do NOT reboot the machine immediately; capture a live memory dump (RAM) first, as there is a slim chance the encryption keys are still resident in memory.",
    "Identify the initial entry vector (e.g., compromised RDP credentials or a specific phishing email) to prevent re-infection during the recovery process.",
    "Restore the affected systems from secure, offline backups that were not accessible to the ransomware during the attack."
  ],
  "what_to_avoid": [
    "Do not pay the ransom unless absolutely necessary, as it funds criminal syndicates and does not guarantee the return of a working decryption key.",
    "Avoid relying on local system restores or shadow copies, as Cryakl explicitly targets and deletes these backups."
  ],
  "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"
  ]
}