Doyo

Overview

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.

Understanding the Doyo Threat
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.

Execution and Browser Hijacking Mechanics
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.

Indicators of Compromise & Impact
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.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_DOYO {
    meta:
        description = "Detects Doyo (advanced_threat)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "doyo" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Doyo Activity
id: 6ac6acaa7fd26efe3f263dedefffe3bb
status: experimental
description: Detects generic indicators of the doyo malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*doyo*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Use the Windows Control Panel to uninstall the primary Doyo application and any bundled software installed on the same date.
2. Run an enterprise-grade Adware/PUA removal tool (like Malwarebytes) to strip the persistent browser extensions and scheduled tasks.
3. Manually inspect and repair all web browser shortcuts (`.lnk` files) to ensure they point directly to the legitimate executable, without appended URLs.
4. Reset all web browsers to their factory default settings to clear hijacked homepages and search engine configurations.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not allow users local administrator rights; standard users generally cannot install the system-level services required by persistent adware like Doyo.
2. Avoid ignoring adware infections; the infrastructure used to deliver Doyo is frequently repurposed to deliver ransomware.

References & External Analysis

• Search "doyo" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: advanced_threat)

Explore other malware families in the same category:

• Offergenerator
• Bunndle
• Speesipro
• Zylom
• Pckeeper

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/doyo.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.