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Malicious Software Encyclopedia: Trojan:Win32/Vundo.gen!D

Published: April 29, 2008

Trojan:Win32/Vundo.gen!D is a component of Win32/Vundo - a multiple-component family of programs that deliver 'out of context' pop-up advertisements. They may also download and execute arbitrary files.
Vundo is often distributed as a DLL file and installed on an affected machine as a Browser Helper Object (BHO) without a user's consent. This family uses advanced defensive and stealth techniques to escape detection and to hinder removal.

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Glossary Terms

Click the term to get the definition from our Security Glossary.

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Trojan horse

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virus

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worm

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On This Page
Threat OverviewThreat Overview
Technical AnalysisTechnical Analysis
How to Prevent InfectionHow to Prevent Infection
How to Tell If Your Computer Is InfectedHow to Tell If Your Computer Is Infected
How to Recover from InfectionHow to Recover from Infection

Threat Overview

Class/typeTrojan - Generic
DiscoveredOctober 7, 2008
CirculatingYes
Affected operating systems
Affected software Not specified
Infection ratingLow
Recovery difficultyEasy
Damage ratingLow
Transmission ratingLow

Technical Analysis

Trojan:Win32/Vundo.gen!D is a component of Win32/Vundo - a multiple-component family of programs that deliver 'out of context' pop-up advertisements. They may also download and execute arbitrary files.
Vundo is often distributed as a DLL file and installed on an affected machine as a Browser Helper Object (BHO) without a user's consent. This family uses advanced defensive and stealth techniques to escape detection and to hinder removal.
 
For more information, please see the Win32/Vundo analysis elsewhere in our encyclopedia.
 
Analysis by Ray Roberts

How to Prevent Infection

Take the following steps to help prevent infection on your system:

  • Enable a firewall on your computer.
  • Get the latest computer updates.
  • Use up-to-date antivirus software.
  • Use caution with attachments and file transfers.

Enable a firewall on your computer

Use a third-party firewall product or turn on the Microsoft Windows XP Internet Connection Firewall.
To turn on the Internet Connection Firewall in Windows XP
  1. Click Start, and click Control Panel.
  2. Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
  3. Click Change Windows Firewall Settings.
  4. Select On.
  5. Click OK.
To turn on the Windows Firewall in Windows Vista
  1. Click Start, and click Control Panel.
  2. Click Security.
  3. Click Turn Windows Firewall on or off.
  4. Select On.
  5. Click OK.

Get the latest computer updates

Updates help protect your computer from viruses, worms, and other threats as they are discovered. You can use the Automatic Updates feature in Windows XP to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows XP
  1. Click Start, and click Control Panel. 
  2. Click System.
  3. Click Automatic Updates.
  4. Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.

Use up-to-date antivirus software

Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software that is updated with the latest signature files. Antivirus software is available from several sources. For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.

Use caution with attachments and file transfers

Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources.  Use extreme caution when accepting file transfers from known or unknown sources.

How to Tell If Your Computer Is Infected

There are no obvious symptoms that indicate the presence of Trojan:Win32/Vundo.gen!D.

How to Recover from Infection

Manual Recovery

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as the Microsoft online scanner (http://safety.live.com). For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.

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