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Malicious Software Encyclopedia: Win32/Gael

Published: September 13, 2005

Win32/Gael is a parasitic virus that targets certain versions of Microsoft Windows. The virus infects Win32 PE .exe files locally and on writeable network shares. The virus can also download TrojanDownloader:Win32/Small from a Web site and run the file.

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Removal Tools - Microsoft

Glossary Terms

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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
Aliases (Also Known As)Aliases (Also Known As)
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
Transmission MethodsTransmission Methods
Payload InformationPayload Information
Affected PortsAffected Ports

Threat Overview

Class/typeVirus - File
Worm - Network
DiscoveredJuly 27, 2005
CirculatingNo
Affected operating systemsWindows NT 4.0
Windows 2000
Windows XP
Windows Server 2003
Affected software Not specified
Infection ratingLow
Recovery difficultyDifficult
Damage ratingMedium
Transmission ratingMedium

Aliases (Also Known As)

Different antivirus vendors may be using different names to refer to this malicious software. Here are some of the names currently in use by antivirus software vendors participating in the Microsoft Virus Information Alliance (VIA):

  • CA: Win32/Gael
  • McAfee: W32/Gael.worm
  • Sophos: W32/Tenga
  • Symantec: W32.Licum
  • Trend Micro: PE_TENGA

    • Learn more about the Microsoft Virus Information Alliance.

    Technical Analysis

    Win32/Gael may take the following actions:
    • Infect Win32 PE .exe files through the IPC$ shares of remote computers.
    • Download TrojanDownloader:Win32/Small from a Web site.
    • Infect all Win32 PE .exe files in all folders on %SystemDrive%.
    • Inject a copy of itself into the winlogon.exe process.
    • Connect to a specified Web server and open a command shell there.
     
    After performing these operations, Win32/Gael passes control to the host program.
     
    Some executable files, such as installer packages, contain data at the end of the file. Win32/Gael truncates executable files that it infects, so any data at the end of the file is deleted.

    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 strong passwords.
    • Remove unneeded network shares.

    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, and click Network Connections. If you do not see Network and Internet Connections, click Switch to Category View.
    3. Highlight a connection that you want to help protect, and click Change settings of this connection.
    4. Click Advanced, and select Protect my computer and network by limiting or preventing access to this computer from the Internet.
    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 Microsoft 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 Performance and Maintenance. If you do not see Performance and Maintenance, click Switch to Category View.
    3. Click System.
    4. Click Automatic Updates, and select Keep my computer up to date.
    5. Select a setting. Microsoft recommends selecting Automatically download the updates, and install them on the schedule that I specify and setting a regular update time.
    6. If you choose to have Automatic Updates notify you in step 5, you will see a notification balloon when new downloads are available to install. Click the notification balloon to review and install updates.

    Use up-to-date antivirus software

    Most antivirus software can detect and prevent infection by known malicious software. You should always run antivirus software on your computer that is updated with the latest signature files to automatically help protect you from infection. If you don't have antivirus software installed, you can get it from one of several companies. For more information, see http://www.microsoft.com/athome/security/downloads/default.mspx

    Use strong passwords

    A strong password has at least eight characters and includes a combination of letters, numbers, and symbols. It is easy for you to remember, but difficult for others to guess. Weak passwords include any words in the dictionary, names, dates, consecutive letters or numbers, common words with symbol substitutions (for example, p@ssw0rd), and so on.

    Remove unneeded network shares

    Malicious software can often spread over network shares. Remove unneeded network shares that are mapped to your computer.
    To remove network shares in Windows XP
    1. On the Start menu, click My Computer.
    2. On the Tools menu, click Disconnect Network Drives…
    3. In the Disconnect Network Drives dialog box, click the drives to disconnect and click OK.

    How to Tell If Your Computer Is Infected

    Win32/Gael may cause excessive network traffic and decreased system performance. Otherwise, there are no readily apparent indications that your computer is infected by this virus.

    How to Recover from Infection

    Automatic Recovery
    To attempt to automatically remove this threat, run one of the following removal tools:

    Transmission Methods

    MethodDescription
    Network SharesInfects Win32 PE .exe files on network shares at random IP addresses.
    Infected FilesInfects all Win32 PE .exe files in all folders on the local disk.

    Payload Information

    Payload typeTriggerDescription
    Compromises Security
    Execution
    • Infects all Win32 PE .exe files in all folders on %SystemDrive%.
    • Injects a copy of itself into the winlogon.exe process.
    Degrades Performance
    Execution
    Starts threads to infect Win32 PE .exe files through IPC$ shares of remote computers.
    Creates files
    Execution
    Downloads TrojanDownloader:Win32/Small.

    Affected Ports

    ProtocolPort number
    TCP139

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