{
  "family": "doyo",
  "sample_count": 6,
  "category": "advanced_threat",
  "description": "Adware:Win32/Doyo is a pervasive Potentially Unwanted Application (PUA) and Adware variant whose primary objective is aggressive monetization through unauthorized advertising injection and browser hijacking. It severely degrades the user experience by hijacking search queries, inserting interstitial ads into legitimate websites, and tracking browsing habits to build marketing profiles, which are then sold to third-party data brokers.<br><br><b>Understanding the Doyo Threat</b><br>To an end-user, Doyo manifests as a sudden, drastic slowdown in web browsing, accompanied by unprompted pop-ups and a changed default search engine. For a corporate IT department, Doyo is a major productivity sink and a security risk, as the injected advertisements frequently link to tech support scams, phishing sites, or exploit kits capable of dropping more severe malware.<br><br><b>Execution and Browser Hijacking Mechanics</b><br>Doyo is almost exclusively distributed via Pay-Per-Install (PPI) bundling networks (`T1189`). When a user downloads freeware (like a PDF converter) from an untrustworthy site, the Doyo installer is silently executed in the background (`T1204.002`). It establishes persistence by creating scheduled tasks (`T1053.005`) and dropping malicious extensions into all installed browsers (Chrome, Edge, Firefox) (`T1176`). It modifies the browser's shortcut files (`.lnk`) to append arguments that force the browser to open Doyo-controlled domains upon launch. It then intercepts web traffic to inject its own HTML/JavaScript advertisements over legitimate page content.<br><br><b>Indicators of Compromise & Impact</b><br>The primary impact is the loss of user productivity and potential exposure to secondary threats. Host-based IoCs include EDR alerts for the modification of browser `.lnk` files on the Desktop or Taskbar, and the presence of unfamiliar, heavily obfuscated browser extensions. Network IoCs include a high volume of HTTP/HTTPS traffic to known adware tracking domains (often fast-flux domains) and a sudden drop in traffic to the organization's approved default search provider.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Doyo and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Doyo is classified as a Advanced Threat. 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 Doyo establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Doyo 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 Doyo compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Doyo 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 lateral movement and credential access tactics does Doyo leverage in enterprise intrusions?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Doyo frequently utilizes privileged account harvesting techniques such as LSASS memory dumping, Kerberoasting, and token impersonation to escalate privileges. Once administrative credentials are acquired, it pivots across the victim network utilizing living-off-the-land binaries (LOLBins) such as WMI, PowerShell remoting, and PsExec, or abuses remote desktop protocols (RDP) to reach critical internal repositories and domain controllers."
      }
    },
    {
      "@type": "Question",
      "name": "How does Doyo maintain covert communications and evade perimeter network monitoring?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Doyo often relies on multi-stage command and control (C2) architectures utilizing encrypted protocols over standard web ports (HTTPS/443 or DNS tunneling) to blend in with legitimate enterprise network traffic. Many variants incorporate proxy networks, domain fronting, or cloud services (such as Microsoft Graph API, Google Drive, or Telegram) to masquerade C2 channels, bypassing traditional signature-based egress filtering."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1204.002",
    "T1562.001",
    "T1189",
    "T1176"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1189",
      "name": "Drive-by Compromise (Software bundling)",
      "tactic": "Initial Access"
    },
    {
      "id": "T1176",
      "name": "Browser Extensions (Malicious add-ons for ad injection)",
      "tactic": "Persistence"
    },
    {
      "id": "T1562.001",
      "name": "Impair Defenses: Disable or Modify Tools (Modifying browser shortcuts)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1204.002",
      "name": "User Execution: Malicious File",
      "tactic": "Execution"
    }
  ],
  "containment_steps": [
    "Use the Windows Control Panel to uninstall the primary Doyo application and any bundled software installed on the same date.",
    "Run an enterprise-grade Adware/PUA removal tool (like Malwarebytes) to strip the persistent browser extensions and scheduled tasks.",
    "Manually inspect and repair all web browser shortcuts (`.lnk` files) to ensure they point directly to the legitimate executable, without appended URLs.",
    "Reset all web browsers to their factory default settings to clear hijacked homepages and search engine configurations."
  ],
  "what_to_avoid": [
    "Do not allow users local administrator rights; standard users generally cannot install the system-level services required by persistent adware like Doyo.",
    "Avoid ignoring adware infections; the infrastructure used to deliver Doyo is frequently repurposed to deliver ransomware."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows Server 2022",
    "Windows Server 2019"
  ]
}