Dnschange

Overview

Trojan:Win32/Dnschange (referencing the infamous **DNSChanger** malware class) is a severe threat designed to silently hijack a victim's web traffic by altering the machine's Domain Name System (DNS) settings at the operating system or router level. By pointing the victim's DNS resolution to rogue servers controlled by the attacker, all web requests (e.g., typing `google.com` or `chase.com`) are transparently redirected to malicious sites, phishing clones, or advertising farms.

Understanding the DNSChanger Threat
To an end-user, a DNSChanger infection is often insidious. The internet still 'works', but they may notice excessive pop-up ads, warnings about invalid SSL certificates, or their search results being subtly altered to prioritize malicious links. For a SOC analyst, unauthorized modification of network adapter DNS settings is a critical compromise that allows the attacker a Man-in-the-Middle (MitM) position over all endpoint traffic.

Execution and DNS Hijacking Mechanics
Dnschange is typically distributed via drive-by downloads (`T1189`) or bundled within deceptive software installers. Upon execution with administrative privileges (`T1204.002`), the malware queries the Windows Registry or uses `netsh` commands (`T1562.001`) to modify the `NameServer` parameters of the active network adapters. It replaces the legitimate ISP or corporate DNS IPs (e.g., `8.8.8.8`) with the IPs of the attacker's rogue DNS infrastructure (`T1565.001`). Some advanced variants also attempt to access the local home router using default credentials (e.g., `admin/admin`) to change the DNS settings at the hardware level, affecting every device on the local network (`T1498.001`).

Indicators of Compromise & Impact
The primary impact is the silent interception of web traffic, mass ad-fraud, and credential theft via perfect phishing replicas. Host-based IoCs include EDR alerts for `netsh.exe` or `ipconfig.exe /flushdns` being executed by unexpected parent processes, or unauthorized modifications to the `HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces` registry keys. Network IoCs include all DNS traffic (UDP Port 53) being routed to unknown, untrusted IP addresses located in foreign jurisdictions.

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_DNSCHANGE {
    meta:
        description = "Detects Dnschange (trojan)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "dnschange" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Dnschange Activity
id: 06d87df8d850c9bd646843a086f3ea9c
status: experimental
description: Detects generic indicators of the dnschange malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*dnschange*"
    condition: selection
level: medium

Containment & Response Steps

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

1. Open the Windows Network Connections control panel, inspect the TCP/IPv4 properties of the active adapter, and manually reset the DNS server addresses to 'Obtain DNS server address automatically' or the corporate standard.
2. Run `ipconfig /flushdns` in an elevated command prompt to clear the poisoned local DNS cache.
3. If the infection occurred on a home network, instruct the user to immediately change their Wi-Fi router's administrator password and verify the router's DNS settings have not been tampered with.
4. Perform a full AV/EDR scan, as DNSChangers are often used to block the victim from reaching antivirus update servers, leaving them vulnerable to secondary payloads.

What to Avoid

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

1. Do not assume a user typing a URL is actually going to that domain if DNS is hijacked; verify the resolved IP address.
2. Avoid simply removing the malware executable; you must manually repair the TCP/IP settings, or the machine will lose internet access entirely when the rogue DNS servers are inevitably taken down by law enforcement.

References & External Analysis

• Search "dnschange" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: trojan)

Explore other malware families in the same category:

• Moonpie
• Regrun
• Harvester
• Skypespam
• Dragonbot

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/dnschange.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.