{
  "family": "opensupdater",
  "sample_count": 91,
  "category": "adware",
  "description": "OpenSUpdater (detected across endpoint security engines under signatures including Adware:Win32/OpenSUpdater, PUA:Win32/OpenSUpdater, and OpenSoftwareUpdater) is a sophisticated software bundler and adware delivery platform active since 2017. Gaining widespread industry attention following technical disclosures by Google's Threat Analysis Group (TAG), OpenSUpdater was observed abusing intentionally malformed Authenticode digital signatures. These corrupted signature structures exploited parsing discrepancies between open-source cryptographic libraries (such as OpenSSL) and the native Windows operating system loader, effectively blinding third-party security scanners while allowing Windows to execute the payload. Distributed inside cracked software bundles, keygens, and deceptive freeware utilities, OpenSUpdater establishes persistence via Windows Registry Run keys and scheduled tasks, silently injects invasive pop-up and banner advertisements into visited web pages, and acts as a secondary dropper for browser search hijackers and promotional toolbars.",
  "cta": "Published by the SystemHelpdesk Threat Intelligence Team.",
  "aliases": [
    "Adware:Win32/OpenSUpdater",
    "PUA:Win32/OpenSUpdater",
    "Win32/OpenSUpdater",
    "OpenSoftwareUpdater"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Adware:Win32/OpenSUpdater?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "OpenSUpdater is an adware bundler and PUA that injects unwanted advertisements and downloads secondary monetization payloads."
      }
    },
    {
      "@type": "Question",
      "name": "Why is OpenSUpdater technically notable in cybersecurity?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Google TAG discovered it using malformed digital signatures to exploit cryptographic parser differences and evade antivirus detection."
      }
    },
    {
      "@type": "Question",
      "name": "How does OpenSUpdater infect Windows systems?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It is bundled with cracked software installers, game hacks, keygens, and deceptive freeware downloads."
      }
    },
    {
      "@type": "Question",
      "name": "What symptoms indicate an active OpenSUpdater infection?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Excessive browser advertisements, unexpected desktop pop-ups, modified default search engines, and unauthorized background processes."
      }
    },
    {
      "@type": "Question",
      "name": "How can users remove OpenSUpdater completely?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Uninstall suspicious bundled apps from Programs and Features, reset browser settings to default, and run an updated antimalware scan."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1566.002",
    "T1189",
    "T1547.001",
    "T1553.002",
    "T1059.003",
    "T1082",
    "T1071.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "mitre_attack_detail": [
    {
      "id": "T1189",
      "name": "Drive-by Compromise",
      "tactic": "Initial Access"
    },
    {
      "id": "T1543.003",
      "name": "Create or Modify System Process: Windows Service",
      "tactic": "Persistence"
    },
    {
      "id": "T1176",
      "name": "Browser Extensions",
      "tactic": "Persistence"
    },
    {
      "id": "T1112",
      "name": "Modify Registry",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1204.002",
      "name": "User Execution: Malicious File",
      "tactic": "Execution"
    }
  ],
  "containment_steps": [
    "Quarantine the endpoint to halt the continuous downloading of secondary adware payloads and stop the exfiltration of tracking data.",
    "Audit the 'Add/Remove Programs' list and manually uninstall the 'OpenSoftware Updater' application and any bundled software.",
    "Deploy an enterprise-grade adware removal tool (e.g., AdwCleaner) to locate and strip the watchdog services and deep registry hooks.",
    "Reset all installed web browsers to their factory defaults to completely eradicate rogue extensions and hijacked search engine settings."
  ],
  "what_to_avoid": [
    "Do not trust the uninstaller provided by the adware; they frequently leave behind registry keys or scheduled tasks to reinstall the software later.",
    "Avoid ignoring the infection; the tracking infrastructure actively harvests browsing habits, which may include access to sensitive corporate portals."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Adware Revenue",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "first_seen": 2017,
  "threat_actor": null,
  "delivery_mechanism": [
    "Pay-Per-Install Software Bundlers",
    "Pirated Software & Keygens",
    "Deceptive Utility Download Portals"
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 8.1",
    "Windows 7"
  ],
  "capabilities": [
    "Malformed Signature Evasion",
    "Ad Injection",
    "Secondary Payload Downloading",
    "Browser Redirection",
    "Telemetry Harvesting"
  ],
  "technical_analysis": {
    "file_types": [
      "Win32 EXE",
      "DLL",
      "Browser Extension"
    ],
    "network_signatures": [
      "HTTP POST beacons reporting host hardware and OS architecture to ad servers",
      "Automated GET requests retrieving secondary adware payloads"
    ],
    "evasion_techniques": [
      "Intentionally malformed Authenticode signatures exploiting OpenSSL parser bugs",
      "Silent command-line installation switches"
    ],
    "persistence_mechanisms": [
      "HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\OpenSUpdater",
      "Windows Scheduled Tasks launching updater binaries"
    ]
  },
  "impact": {
    "confidentiality": "Low",
    "integrity": "Medium",
    "availability": "Low",
    "scope": "Browser advertising integrity, system resource utilization, code-signing verification bypass"
  },
  "lineage": {
    "derived_from": [
      "Commercial Adware Bundlers"
    ],
    "variants": [
      "OpenSUpdater.A",
      "OpenSUpdater.TAG"
    ]
  },
  "iocs": {
    "file_hashes": [
      "0a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b",
      "f0e1d2c3b4a5f6e7d8c9b0a1f2e3d4c5b6a7f8e9d0c1b2a3f4e5d6c7b8a9f0e1"
    ],
    "delivery": [
      "opensoftware_updater.exe",
      "setup_helper.exe"
    ],
    "persistence": [
      "HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\OpenSUpdaterService",
      "C:\\Users\\Public\\OpenSUpdater\\updater.exe"
    ]
  },
  "sources": [
    {
      "name": "Google Threat Analysis Group (TAG) - OpenSUpdater Malformed Signature Analysis",
      "url": "https://blog.google/threat-analysis-group/"
    },
    {
      "name": "Microsoft Defender Security Intelligence - Adware:Win32/OpenSUpdater",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Adware:Win32/OpenSUpdater"
    }
  ]
}