Dnschanger

Overview

DNSChanger is one of the largest and most commercially damaging malware operations in internet history, first detected in 2007. Operated by Estonian cybercriminal Vladimir Tsastsin and his front company 'Rove Digital' in Tartu, Estonia, DNSChanger covertly modified Domain Name System (DNS) server configuration settings on infected computers and local home routers, redirecting all outbound internet web traffic through an illicit network of rogue DNS servers hosted in New York and Chicago. By hijacking DNS resolution, the operators silently intercepted web traffic from over 4 million compromised computers in more than 100 countries—including over 500,000 systems in the United States, penetrating internal networks at NASA and the Department of Defense. When victims visited popular websites (such as Amazon, Netflix, or search engines), the rogue DNS servers redirected them to spoofed advertising networks, generating over $14 million in fraudulent ad revenue. In November 2011, the FBI and Estonian Police executed 'Operation Ghost Click', arresting Tsastsin and five accomplices in Estonia. Because abruptly terminating the rogue DNS servers would have severed internet access for millions of users worldwide, the US federal court authorized the Internet Systems Consortium (ISC) to operate clean surrogate DNS servers for eight months until July 2012 while global remediation took place. Tsastsin was extradited to the US, pleaded guilty in SDNY federal court, and was sentenced to federal prison in 2016.

Known aliases

Threat reports may refer to this family under multiple names:

• DNSChanger
• Trojan.DNSChanger
• Win32/DNSChanger
• OSX.DNSChanger
• Rove Digital

Threat Actor Attribution

Attribution is probabilistic, not a science. Each link below states its confidence level and the evidence behind it.

• Vladimir Tsastsin (Rove Digital) / FBI Operation Ghost Click (SDNY Conviction) High confidence
  Basis: Estonian national Vladimir Tsastsin and five co-conspirators were arrested in Estonia in November 2011 during Operation Ghost Click. Tsastsin was extradited to the US and sentenced to federal prison in the Southern District of New York in 2016. [source]

Family Pedigree & Lineage

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

Known Derivatives & Downstream Variants: Dnschanger Windows Pe · Osx.Dnschanger (Mac Os X Variant) · Dnschanger Router Brute-Force Module

MITRE ATT&CK Techniques

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

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-2008-1447 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).

Command & Control (C2) and Network Profile

How this family talks to its operators. C2 traffic can often identify a family even when its code and configuration are hard to analyse. Ports and patterns are historical and change between campaigns, so use them as hunting leads rather than block-only rules.

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.

• 2efb6d17b5e4c6981cfda552553ca4be969796ff07a835a96aef71a2ec703ce5
• b1b4c330f89fa6d165f973e20e8b22a08846c4f09a5b3a8634860b0ec89c565d

Delivery vectors

• Drive-by downloads disguised as video codec updates on untrusted multimedia streaming websites
• Malvertising redirects exploiting browser and media player vulnerabilities

Persistence mechanisms

• Direct alteration of TCP/IP registry settings (NameServer and DhcpNameServer keys in Windows registry)
• Automated HTTP brute-force attacks against local gateway routers to alter router-level DNS settings

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_DNSCHANGER_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Dnschanger"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "dnschanger" ascii wide nocase
        $s2 = "dnschanger" ascii wide nocase
        $s3 = "trojan.dnschanger" ascii wide nocase
        $s4 = "win32/dnschanger" ascii wide nocase
        $s5 = "osx.dnschanger" ascii wide nocase
        $s6 = "rove digital" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Dnschanger (Trojan) Execution & Triage
id: 5024f2bc-d251-5ac3-99a1-34864523abb9
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Dnschanger 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/dnschanger
- https://malware-families-catalog.systemhelpdesk.com/defensive/downloader-dropper-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.trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1565_001
- attack.t1071_004
- attack.t1112
- attack.t1200
- 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_DNSCHANGER_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Dnschanger 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 = "dnschanger" 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. Open the Windows Network Adapter settings (or `ipconfig /all`) and verify the configured DNS servers against known good corporate or ISP resolvers.
2. If rogue IPs are found, flush the DNS cache (`ipconfig /flushdns`) and manually reset the adapter settings to use DHCP or legitimate DNS servers (like 8.8.8.8).
3. Run a full antivirus scan to remove the underlying trojan that caused the modification; simply changing the DNS back is insufficient if the malware is still running.
4. Monitor enterprise DNS logs for any endpoints attempting to resolve queries against the known rogue Dnschanger subnets.

What to Avoid

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

1. Do not assume the internet is 'just broken'; a sudden inability to reach specific sites (especially AV vendors) while others work is a classic sign of DNS hijacking.
2. Avoid ignoring the root cause; you must find and remove the dropper executable, or the DNS settings will be hijacked again upon reboot.

References & External Analysis

• US DOJ SDNY Press Release - Extradition and Sentencing of Vladimir Tsastsin
• FBI National Press Release - Operation Ghost Click
• CISA Advisory - DNSChanger Remediation and Working Group
• Search "dnschanger" on VirusTotal (External Analysis)
• Search "dnschanger" on Any.Run (Sandbox Sandbox)
• Search "dnschanger" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Explorerhijack
• Tpyn
• Joker
• Adwind
• Trojna
• Moleboxvs
• Zamg
• Zebrocy

Machine-readable

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