{
  "family": "dnscleaner",
  "sample_count": 14,
  "category": "advanced_threat",
  "description": "Adware:Win32/Dnscleaner is a deceptive adware framework and Potentially Unwanted Program (PUA) that silently infiltrates endpoints, typically bundled with freeware, to inject intrusive advertisements, hijack browser settings, and harvest user search telemetry for affiliate monetization.<br><br><b>What is Dnscleaner?</b><br>To the average user, Dnscleaner is highly visible and deeply frustrating. The browser homepage is forcibly changed, default search engines are locked to unfamiliar domains, and standard websites are flooded with injected banner ads or in-text hyperlinks. For security analysts, Dnscleaner operates on the Pay-Per-Install (PPI) model. It leverages deceptive installation tactics and aggressive persistence mechanisms to ensure the user cannot easily revert their browser settings, guaranteeing continued revenue generation for the attackers.<br><br><b>Infection Vectors & Threat Hunting</b><br>Dnscleaner is almost exclusively distributed via deceptive software bundlers. When a user downloads a free PDF editor or media player from a third-party site, the Dnscleaner wrapper executes first. It employs 'Dark Patterns'—pre-checked boxes hidden behind 'Advanced' menus—to gain technical consent. Upon execution, it installs malicious browser extensions and frequently leverages Windows Group Policy (GPO) settings (`ExtensionInstallForcelist`) to lock the rogue extensions in place. It establishes persistence via Registry Run keys and scheduled tasks. Notably, it may also alter local DNS settings to hijack web traffic.<br><br><b>Forensic Analysis & Impact</b><br>The primary impact is a severely degraded user experience, compromised browsing privacy, and wasted helpdesk resources. Incident responders will observe anomalous HTTP/HTTPS traffic to known ad-tracking networks. EDR logs will show the initial installer attempting to modify browser preference files (e.g., Chrome's `Preferences` JSON file) and establishing unauthorized Group Policies.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1105",
    "T1562.001",
    "T1176",
    "T1189",
    "T1112"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1189",
      "name": "Drive-by Compromise",
      "tactic": "Initial Access"
    },
    {
      "id": "T1562.001",
      "name": "Impair Defenses: Disable or Modify Tools (DNS Hijacking)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1176",
      "name": "Browser Extensions",
      "tactic": "Persistence"
    },
    {
      "id": "T1112",
      "name": "Modify Registry",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1105",
      "name": "Ingress Tool Transfer",
      "tactic": "Command and Control"
    }
  ],
  "containment_steps": [
    "Quarantine the endpoint to halt the active exfiltration of browsing telemetry and the downloading of further adware modules.",
    "Check and reset the Windows network adapter's DNS settings (IPv4) to ensure they are pointing to legitimate corporate or ISP servers.",
    "Deploy an enterprise adware removal tool (e.g., AdwCleaner) to locate and strip the deeply embedded registry hooks and watchdog services.",
    "Force a complete reset of all installed web browsers to factory defaults to eradicate the rogue extensions and restore the homepage."
  ],
  "what_to_avoid": [
    "Do not rely solely on the browser's 'remove extension' button; Dnscleaner frequently uses GPOs and watchdog services to immediately reinstall itself.",
    "Avoid ignoring the infection; adware tracking data is highly detailed and may expose corporate activities or access to internal portals."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}