{
  "family": "reveton",
  "sample_count": 4,
  "category": "ransomware",
  "description": "Ransom:Win32/Reveton represents a historically significant evolutionary step in cyber extortion, commonly known as **'Police Ransomware' or a 'Screen Locker'**. Predating the widespread use of modern crypto-ransomware (which encrypts files), Reveton operated entirely on social engineering and intimidation. It locked the victim's computer screen, preventing access to the Windows desktop, and displayed a highly realistic, localized warning message claiming to be from the FBI, Interpol, or local law enforcement. The message accused the user of illegal activities (such as downloading pirated media or viewing child pornography) and demanded an immediate 'fine' paid via prepaid vouchers like Ukash, Paysafecard, or MoneyPak.<br><br><b>Understanding Reveton (Screen Lockers)</b><br>To an end-user, Reveton was terrifying; the computer was completely unusable, the warning looked official (often featuring logos of local police), and it frequently utilized the victim's webcam to display a live feed of their face on the ransom note, maximizing the psychological pressure. For a SOC analyst, Reveton was a nuisance malware that relied on restricting access to the shell, rather than destroying data. However, later variants were often bundled with password stealers (like Citadel or Zeus) acting in the background.<br><br><b>Execution and Locking Mechanics</b><br>Reveton was primarily distributed via Exploit Kits (like Blackhole or Cool EK) hosted on compromised websites or malvertising networks (`T1189`). When a vulnerable browser navigated to the site, the exploit executed the Reveton payload silently (`T1203`). Upon execution, Reveton immediately established persistence, often by modifying the `Winlogon\\Shell` registry key (`T1547.004`). Instead of loading `explorer.exe` on boot, Windows would load the Reveton executable. The malware then launched a full-screen, borderless window (`T1491.001`) that could not be closed via Alt+F4 or Task Manager (`T1562.001`). It determined the victim's geographic location via IP address (`T1614.001`) to display a customized ransom note in the local language, citing local laws.<br><br><b>Indicators of Compromise & Impact</b><br>The impact was a complete denial of service to the workstation, though data was usually unharmed. Host-based IoCs were obvious: the inability to access the desktop, Task Manager, or Start menu, and the presence of anomalous executables in the `Winlogon\\Shell` or `Userinit` registry keys. Network IoCs included traffic to C2 servers to download the localized HTML/image templates for the ransom note.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Reveton and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Reveton 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 Reveton establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Reveton 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 Reveton compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Reveton 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 Reveton employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Reveton 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 Reveton, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Reveton 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": [
    "T1562.001",
    "T1547.004",
    "T1491.001",
    "T1189"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1491.001",
      "name": "Defacement: Internal Defacement (The full-screen Police warning)",
      "tactic": "Impact"
    },
    {
      "id": "T1547.004",
      "name": "Boot or Logon Autostart Execution: Winlogon Helper DLL (Hijacking the Shell)",
      "tactic": "Persistence"
    },
    {
      "id": "T1562.001",
      "name": "Impair Defenses: Disable or Modify Tools (Blocking Task Manager/Safe Mode)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1189",
      "name": "Drive-by Compromise (Exploit Kits)",
      "tactic": "Initial Access"
    }
  ],
  "containment_steps": [
    "Do not pay the 'fine'; it is a scam, and law enforcement agencies do not lock computers and demand prepaid vouchers.",
    "Boot the infected machine into 'Safe Mode with Command Prompt' or use a bootable USB rescue disk (like a WinPE environment) to bypass the `Winlogon` hijack.",
    "Use the offline Registry Editor (`regedit`) to navigate to `HKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon` and restore the `Shell` value to `explorer.exe`.",
    "Once access is restored, run a comprehensive malware scan, as Reveton was often distributed alongside banking trojans (like Citadel) that operated silently in the background."
  ],
  "what_to_avoid": [
    "Avoid confronting the user about the accusations on the screen (e.g., piracy); the warnings are completely fabricated and generated for all victims regardless of their actual browsing history.",
    "Do not simply reboot the computer normally; the persistence mechanism ensures the locker will immediately re-engage upon login."
  ],
  "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"
  ]
}