1. Symantec/
  2. Security Response/
  3. W32.Gibe@mm


Risk Level 2: Low

March 4, 2002
February 13, 2007 11:50:21 AM
Also Known As:
W32/Gibe@mm, WORM_GIBE.A, W32/Gibe-A, I-Worm.Gibe, W32/Gibe.A@mm, Win32.Gibe.A, W32/Gibe@MM
Trojan Horse, Worm
Systems Affected:

The fake message, which is not from Microsoft, has the following characteristics:

From: Microsoft Corporation Security Center
Subject: Internet Security Update
Microsoft Customer,
this is the latest version of security update, the update which eliminates all known security vulnerabilities affecting Internet Explorer and MS Outlook/Express as well as six new vulnerabilities
How to install
Run attached file q216309.exe
How to use
You don't need to do anything after installing this item.
Attachment: Q216309.exe

The attached file, Q216309.exe, is written in Visual Basic; it contains other worm components inside itself. When the attached file is executed, it does the following:

It creates the following files:
  • \Windows\Q216309.exe (122,880 bytes). This is the whole package containing the worm.
  • \Windows\Vtnmsccd.dll (122,880 bytes). This file is the same as Q216309.exe.
  • \Windows\BcTool.exe (32,768 bytes). This is the worm component that spreads using Microsoft Outlook and SMTP.
  • \Windows\GfxAcc.exe (20,480 bytes). This is the Backdoor Trojan component of the worm that opens port 12378.
  • \Windows\02_N803.dat (size varies). This is the data file that the worm creates to store email addresses that it finds.
  • \Windows\WinNetw.exe (20,480 bytes). This is the component that searches for email addresses and writes them to 02_N803.dat.

NOTE: Norton AntiVirus detects all of these files as W32.Gibe@mm except the 02_N803.dat. file, which contains only data.

The worm is also network aware. It attempts to locate the Startup folder on all mapped network drives, as follows:
  • Windows 2000. On Windows 2000 computers, it attempts to copy itself to:

    \Documents and Settings\%Infected Computer User Name%\Start Menu\Programs\Startup.

    NOTE: %Infected Computer User Name% is a variable. For example, if the logged in user of the infected computer is "Administrator," it would copy itself to:

    \Documents and Settings\Administrator\Start Menu\Programs\Startup

    on the remote computer.
  • Windows 98. On Windows 98 computers, it attempts to copy itself to:

    \Windows\Start Menu\Programs\Startup

    on the remote computer.
  • Windows NT. On Windows NT Computers, it attempts to copy itself to:

    \Winnt\Profiles\%Infected Computer User Name%\Start Menu\Programs\Startup

    NOTE: %Infected Computer User Name% is a variable. For example, if the logged in user of the infected computer is "Administrator," it would copy itself to:

    \Winnt\Profiles\Administrator\Start Menu\Programs\Startup

    on the remote computer.

Next, the worm then adds the following values:

LoadDBackUp C:\Windows\BcTool.exe
3Dfx Acc C:\Windows\GFXACC.exe

to the registry key


The worm also creates the key


and adds the following values to that key:

Installed ... by Begbie
Default Address <Default Email Address>
Default Server <Default Server>

Finally, BcTool.exe attempts to send the \Windows\Q216309.exe file to email addresses in the Microsoft Outlook address book, and to addresses that it found in .htm, .html, .asp, and .php files and wrote to the 02_N803.dat file.


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Gor Nazaryan
Summary| Technical Details| Removal

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