{
  "family": "pornoblocker",
  "sample_count": 11,
  "category": "ransomware",
  "description": "Ransomware:Win32/Pornoblocker (often categorized generically as a **Winlocker** or Screenlocker) represents a classic, historical evolutionary step in ransomware. Prominent in the late 2000s and early 2010s, this malware did *not* encrypt files. Instead, it aggressively locked the user's desktop interface, displaying a full-screen, highly embarrassing image (often pornographic or claiming to be from law enforcement regarding illegal pornography), and demanded a fine (often via SMS or prepaid cards) to unlock the machine.<br><br><b>Understanding Pornoblocker (Winlocker)</b><br>To a victim, a Pornoblocker infection was an immediate, panic-inducing event. The computer became entirely unusable; the screen was locked, the keyboard was often disabled, and Task Manager was blocked. The social engineering relied entirely on shame and fear. For a security analyst, these early screenlockers were relatively simplistic. Because they didn't utilize complex cryptography, the data was never actually lost, just rendered temporarily inaccessible by aggressive UI manipulation.<br><br><b>Execution and Screen Locking Mechanics</b><br>Pornoblocker was typically distributed via drive-by downloads on illicit websites or peer-to-peer networks (`T1189`). Upon execution, the malware established persistence, often by modifying the critical `Shell` value in the Registry (`HKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon`). Instead of launching `explorer.exe` (the normal Windows desktop), Windows would launch the malware executable at boot (`T1547.004`). The malware created a full-screen, always-on-top window (`T1491`), aggressively killed `taskmgr.exe` if the user tried to open it, and hooked the keyboard (`T1056.001`) to block `Alt+Tab` or `Ctrl+Alt+Del`. The screen displayed the ransom demand, forcing the user to pay to remove the lock.<br><br><b>Indicators of Compromise & Impact</b><br>The impact was extreme disruption of use and psychological distress/extortion, but no actual data destruction. Detection was obvious due to the locked screen. Incident responders would boot the machine into Safe Mode (which often bypassed the modified Winlogon Shell registry key) or use offline registry editors to identify the unauthorized executable set to launch in place of `explorer.exe`.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Pornoblocker and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Pornoblocker 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 Pornoblocker establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Pornoblocker 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 Pornoblocker compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Pornoblocker 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 Pornoblocker employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Pornoblocker 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 Pornoblocker, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Pornoblocker 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": [
    "T1491",
    "T1547.004",
    "T1562.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1491",
      "name": "Defacement (Screenlocking / UI Manipulation)",
      "tactic": "Impact"
    },
    {
      "id": "T1547.004",
      "name": "Boot or Logon Autostart Execution: Winlogon Helper DLL (Shell Modification)",
      "tactic": "Persistence"
    },
    {
      "id": "T1562.001",
      "name": "Impair Defenses: Disable or Modify Tools (Killing Task Manager)",
      "tactic": "Defense Evasion"
    }
  ],
  "containment_steps": [
    "Do not pay the ransom; the data is not encrypted, and paying the 'fine' rarely results in the screen unlocking.",
    "Reboot the infected machine into Windows Safe Mode with Command Prompt. This often bypasses the malware's autostart mechanism.",
    "Open the Registry Editor (`regedit`) and navigate to `HKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon`. Change the `Shell` value back to `explorer.exe`.",
    "Locate and delete the malicious executable that was previously listed in the Shell registry key."
  ],
  "what_to_avoid": [
    "Do not reformat the hard drive unnecessarily; the files are perfectly safe and accessible once the registry key is fixed.",
    "Avoid paying via SMS or prepaid cards, as this directly funds the cybercriminal operation."
  ],
  "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"
  ]
}