Zdengo

Overview

Zdengo (frequently classified by security solutions as Adware.Zdengo, Trojan:Win32/Zdengo, Zdengo.A, and PUA:Win32/Zdengo) is a persistent adware installer, click-fraud bot, and potentially unwanted program targeting Windows systems. Distributed via deceptive download managers, repackaged open-source software, and malicious software cracks, Zdengo hooks into system network communications and installed web browsers. Once installed, it forcefully generates unsolicited intrusive pop-up advertisements, redirects web search queries to affiliate marketing hubs, injects promotional banner ads into benign websites, and generates automated fraudulent ad impressions. Zdengo establishes persistence by writing autostart entries into the Windows Registry and creating recurring scheduled tasks.

Known aliases

Threat reports may refer to this family under multiple names:

• Adware.Zdengo
• Trojan:Win32/Zdengo
• Zdengo.A
• Win32/Zdengo
• PUA:Win32/Zdengo

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: Adware Bundler Frameworks

Known Derivatives & Downstream Variants: Zdengo.A · Zdengo.B · Win32/Zdengo.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.
• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

MITRE D3FEND™ Defensive Countermeasures

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

Exploited Vulnerabilities (CVEs)

This malware family is documented weaponizing the following common vulnerabilities and exposures:

• CVE-2010-2568 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).

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
• 7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b

Delivery vectors

• Bundled software installers downloaded from deceptive third-party hosting portals
• Malvertising campaigns redirecting users to fake application download links

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\ZdengoUpdater
• Scheduled task registered under Windows Task Scheduler as 'ZdengoService'

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_ZDENGO_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Zdengo"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "zdengo" ascii wide nocase
        $s2 = "adware.zdengo" ascii wide nocase
        $s3 = "trojan:win32/zdengo" ascii wide nocase
        $s4 = "zdengo.a" ascii wide nocase
        $s5 = "win32/zdengo" ascii wide nocase
        $s6 = "pua:win32/zdengo" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Zdengo (Adware) Execution & Triage
id: d1cf8b1f-4d2c-5449-bc11-2f1b035edf37
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Zdengo 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/zdengo
- 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.t1112
- attack.t1547_001
- attack.t1071_001
- attack.t1105
- attack.t1562_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_ZDENGO_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Zdengo 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 = "zdengo" 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. Terminate active Zdengo processes and uninstall suspicious recent installations from Control Panel.
2. Delete scheduled tasks and registry keys under HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
3. Reset browser configurations to defaults and purge rogue browser extensions.
4. Execute an on-demand scan using reputable antimalware software to detect any secondary dropped components.

What to Avoid

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

1. Do not install repackaged or cracked software distributed across unverified third-party websites.
2. Avoid granting administrative installation permissions to unrecognized utility wrappers.

References & External Analysis

• Malwarebytes Labs - Adware.Zdengo Removal Guide
• Microsoft Defender Security Intelligence - Trojan:Win32/Zdengo
• NIST National Vulnerability Database - CVE-2010-2568
• Search "zdengo" on VirusTotal (External Analysis)
• Search "zdengo" on Any.Run (Sandbox Sandbox)
• Search "zdengo" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Adware)

Explore other documented threats in the same operational category:

• Spigot
• Opendownloadmanager
• Hijacker
• Swizzor
• Autofixerpro
• Yobrowser
• Shyape
• Gjue

Machine-readable

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