{
  "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": [],
  "faq_count": 0,
  "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": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}