Dotdo

Overview

Dotdo (tracked across enterprise antivirus vendors as Adware:Win32/Dotdo, Trojan:Win32/Dotdo, and Adware.DotDo) is a persistent adware engine and local network proxy hijacker documented by Microsoft Defender, Trend Micro, and Malwarebytes. Dotdo is commonly delivered through deceptive software installers, pirated software cracks, and drive-by download pop-ups. Once active on a host, Dotdo establishes a local proxy listener on a dynamic high-numbered TCP port and reconfigures Windows Internet Settings (ProxyServer and AutoConfigURL) under HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings to route all web browser traffic through its local interception engine. By intercepting outbound HTTP and HTTPS sessions, Dotdo injects unwanted commercial banner ads, pop-under windows, and sponsored affiliate search results into visited web pages. Furthermore, Dotdo actively hooks DNS queries and blocks connections to security vendor update domains and endpoint detection telemetry endpoints, effectively undermining host defense posture. It sustains long-term persistence through registry auto-start keys and hidden Windows services.

Known aliases

Threat reports may refer to this family under multiple names:

• Adware:Win32/Dotdo
• Trojan:Win32/Dotdo
• Win32/Dotdo
• Adware.DotDo
• PUA.Win32.DotDo

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Windows_Proxy_Injector_Framework

Known Derivatives & Downstream Variants: Dotdo.A · Trojan.Dotdo.Gen

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4
• d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4e5

Delivery vectors

• Pirated software distribution hubs and keygen utilities bundled with malicious droppers
• Deceptive browser push notification campaigns prompting users to install software updates

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\DotdoAgent
• HKLM\System\CurrentControlSet\Services\DotdoProxyService

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_DOTDO_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Dotdo"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "dotdo" ascii wide nocase
        $s2 = "adware:win32/dotdo" ascii wide nocase
        $s3 = "trojan:win32/dotdo" ascii wide nocase
        $s4 = "win32/dotdo" ascii wide nocase
        $s5 = "adware.dotdo" ascii wide nocase
        $s6 = "pua.win32.dotdo" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Dotdo (Adware) Execution & Triage
id: 63dabacb-788e-53c5-acdd-fae94f0e4969
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Dotdo malware family. Detects suspicious execution from temporary user
  directories with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/dotdo
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.adware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1189
- attack.t1547_001
- attack.t1112
- attack.t1562_001
- attack.t1071_001
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \cscript.exe
    - \wscript.exe
    CommandLine|contains:
    - AppData\Local\Temp
    - -WindowStyle Hidden
    - /e:jscript
    - bitsadmin /transfer
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: medium

rule MALWARE_WIN_DOTDO_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Dotdo tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "dotdo" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

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

1. Quarantine the infected system to prevent interception of credentials and session tokens through the local proxy.
2. Reset Windows Internet Settings proxy configuration by disabling ProxyServer and AutoConfigURL entries.
3. Kill unauthorized background processes listening on local loopback ports (127.0.0.1) associated with the Dotdo service.
4. Run a full system scan with Malwarebytes or Microsoft Defender to remove all persistent binary components and driver hooks.

What to Avoid

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

1. Do not ignore unexpected browser certificate warnings or proxy redirection prompts.
2. Avoid running untrusted software activators and cracks that require disabling Windows Defender real-time protection.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Adware:Win32/Dotdo Analysis
• Malwarebytes Labs Threat Intelligence - Adware.DotDo Research
• Trend Micro Threat Encyclopedia - PUA.Win32.DotDo Details
• Search "dotdo" on VirusTotal (External Analysis)
• Search "dotdo" on Any.Run (Sandbox Sandbox)
• Search "dotdo" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Adware)

Explore other documented threats in the same operational category:

• Elemental
• Trymedia
• Mailru
• Fontra
• Primarypass
• Crossrider
• Unwaders
• Zdengo

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/dotdo.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.