{
  "family": "dnscleaner",
  "sample_count": 14,
  "category": "pua",
  "description": "DNSCleaner (classified across security vendors as PUA:Win32/DNSCleaner and Rogue:Win32/DNSCleaner) is a scareware system optimizer and Potentially Unwanted Application that deceives users regarding the safety and performance of their Windows network configuration. Installed via third-party software bundles or misleading browser alerts, DNSCleaner initiates automated scans that falsely claim the user's DNS cache, hosts file, and network registry keys are severely corrupted or hijacked by malware. It presents alarming full-screen warnings coercing the user to buy a paid software activation key to repair the DNS settings, while writing persistence entries to HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run and installing background telemetry services.",
  "cta": "Published by the SystemHelpdesk Threat Intelligence Team.",
  "aliases": [
    "PUA:Win32/DNSCleaner",
    "Rogue:Win32/DNSCleaner",
    "Program:Win32/DNSCleaner",
    "DNSCleaner Utility",
    "Win32/DNSCleaner"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is PUA:Win32/DNSCleaner?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "DNSCleaner is a scareware utility that fabricates network and DNS registry errors to deceive users into buying software licenses."
      }
    },
    {
      "@type": "Question",
      "name": "Are the DNS errors reported by DNSCleaner genuine?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "No. DNSCleaner flags routine network cache entries and benign registry settings as critical network vulnerabilities."
      }
    },
    {
      "@type": "Question",
      "name": "How does DNSCleaner gain installation on endpoints?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It is bundled into freeware downloaders, pirated software installers, and deceptive online browser security warnings."
      }
    },
    {
      "@type": "Question",
      "name": "How does DNSCleaner maintain persistence?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It creates autostart entries under Windows Run registry keys and registers scheduled tasks to display warning pop-ups."
      }
    },
    {
      "@type": "Question",
      "name": "How can users completely remove DNSCleaner?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Uninstall DNSCleaner via Windows Installed Apps, delete leftover program files, and perform an antimalware scan."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1491",
    "T1547.001",
    "T1053.005",
    "T1112",
    "T1082"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "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"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "sources": [
    {
      "name": "Microsoft Defender Threat Encyclopedia - PUA:Win32/DNSCleaner",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=PUA:Win32/DNSCleaner"
    },
    {
      "name": "Trend Micro Security Research - PUA.Win32.DNSCleaner Analysis",
      "url": "https://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/pua.win32.dnscleaner"
    },
    {
      "name": "MITRE ATT&CK - Defacement: Displaying Fake Security Alerts (T1491)",
      "url": "https://attack.mitre.org/techniques/T1491/"
    }
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 7"
  ]
}