{
  "family": "jigsawlocker",
  "sample_count": 4,
  "category": "ransomware",
  "description": "Ransom:Win32/Jigsawlocker (commonly known as Jigsaw) is an exceptionally cruel and psychologically manipulative crypto-ransomware family. Unlike standard ransomware that simply encrypts files and waits for payment, Jigsaw employs a sadistic countdown timer, threatening to permanently delete a batch of files every hour until the ransom is paid, often using imagery of the 'Billy the Puppet' character from the *Saw* horror film franchise to induce panic.<br><br><b>Understanding Jigsaw (Extortion/Time-Bomb Ransomware)</b><br>To an end-user, Jigsaw is terrifying. Upon execution, it displays a full-screen, unclosable window with a countdown timer, explicitly stating that if the computer is rebooted or if the user attempts to remove the malware, a massive penalty (e.g., the immediate deletion of 1,000 files) will be enforced. For an incident responder, Jigsaw requires a highly delicate approach; standard remediation tactics (like a hard reboot) will actually trigger the malware's destructive mechanisms.<br><br><b>Execution and Extortion Mechanics</b><br>Jigsaw is typically distributed via spam emails or adware bundles (`T1566.001`). Upon execution, it encrypts user files (often using AES) and appends extensions like `.fun`, `.btc`, or `.jigsaw` (`T1486`). It establishes persistence via the `HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run` registry key (`T1547.001`). The defining characteristic is its extortion mechanism (`T1485` - Data Destruction). The malware monitors system uptime and its own process state. It deletes one file after the first hour, and exponentially increases the number of deleted files every subsequent hour. If the user terminates the Jigsaw process (e.g., via Task Manager) or reboots the machine, the malware detects this upon restart and punishes the user by deleting a large swath of files immediately.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is severe data loss and intense psychological pressure. Host-based IoCs include files renamed with Jigsaw-specific extensions, the presence of the full-screen 'Saw' ransom note, and the active deletion of files in user directories. EDR alerts will show a specific executable (often named `drpbx.exe` or `firefox.exe` to blend in) rapidly performing file deletion APIs.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Jigsawlocker and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Jigsawlocker 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 Jigsawlocker establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Jigsawlocker 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 Jigsawlocker compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Jigsawlocker 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 Jigsawlocker employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Jigsawlocker 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 Jigsawlocker, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Jigsawlocker 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",
    "T1491.001",
    "T1485",
    "T1547.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1486",
      "name": "Data Encrypted for Impact",
      "tactic": "Impact"
    },
    {
      "id": "T1485",
      "name": "Data Destruction (Deleting files on a timer/reboot)",
      "tactic": "Impact"
    },
    {
      "id": "T1491.001",
      "name": "Defacement: Internal Defacement (Full-screen ransom note)",
      "tactic": "Impact"
    },
    {
      "id": "T1547.001",
      "name": "Boot or Logon Autostart Execution",
      "tactic": "Persistence"
    }
  ],
  "containment_steps": [
    "CRITICAL: Do NOT turn off or reboot the infected machine, and do NOT attempt to kill the Jigsaw process via Task Manager, as this triggers the punitive file deletion routine.",
    "Immediately physically disconnect the machine from the network (pull the Ethernet cable).",
    "In a controlled environment, use specialized anti-ransomware tools to freeze the Jigsaw process in memory (suspending the thread) before attempting removal.",
    "Fortunately, older versions of Jigsaw contain cryptographic flaws, and free decryption tools are widely available from security vendors (e.g., No More Ransom)."
  ],
  "what_to_avoid": [
    "Do not panic and pay the ransom; free decryptors exist for many Jigsaw variants.",
    "Absolutely avoid rebooting the computer or forcefully terminating the malware process until the files have been backed up or a decryptor is ready."
  ],
  "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"
  ]
}