Discovered: March 04, 2002
Updated: 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
Type: Trojan Horse, Worm
Systems Affected: Windows

W32.Gibe@mm is a worm that uses Microsoft Outlook and its own SMTP engine to spread. This worm arrives in an email message--which is disguised as a Microsoft Internet Security Update--as the attachment Q216309.exe. The worm also attempts to copy itself to all locally mapped remote drives.

It has been discovered that this worm may distribute corrupted copies of itself which are non-functional. Virus definitions dated March 11, 2002 or later will detect these as W32.Gibe.dam. Files detected as such must be deleted.

Antivirus Protection Dates

  • Initial Rapid Release version March 05, 2002
  • Latest Rapid Release version September 22, 2016 revision 004
  • Initial Daily Certified version March 05, 2002
  • Latest Daily Certified version September 22, 2016 revision 025
  • Initial Weekly Certified release date March 06, 2002

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Technical Description

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.


The preferred way to remove this worm is to use the W32.Gibe@mm Removal Tool . If for any reason you cannot obtain the tool, you must remove the worm manually.

To remove this worm:

  1. Update your virus definitions.
  2. Restart the computer in Safe mode.
  3. Run a full system scan and delete files that are detected as W32.Gibe@mm, and then delete the 02_N803.dat file.
  4. Remove the key and values that the worm added to the registry.

NOTE: Windows Me and Windows XP users should turn off System Restore. This feature, which is enabled by default, is used by Windows Me/XP to restore files on your computer in case they become damaged. When a computer is infected with a virus, it is possible that the virus could be backed up by System Restore. By default, Windows prevents System Restore from being modified by outside programs. As a result, there is the possibility that you could accidentally restore a virus-infected file, or that on-line scanners would detect the virus in that location. For instructions on how to turn off System Restore, read your Windows documentation or one of the following articles:
To update virus definitions:
Obtain the most recent virus definitions. There are two ways to do this:
  • Run LiveUpdate. LiveUpdate is the easiest way to obtain virus definitions. These virus definitions have undergone full quality assurance testing by Symantec Security Response and are posted to the LiveUpdate servers one time each week (usually Wednesdays) unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, look at the Virus Definitions (LiveUpdate) line at the top of this write-up.
  • Download the definitions using the Intelligent Updater. Intelligent Updater virus definitions have undergone full quality assurance testing by Symantec Security Response. They are posted on U.S. business days (Monday through Friday). They must be downloaded from the Symantec Security Response Web site and installed manually. To determine whether definitions for this threat are available by the Intelligent Updater, look at the Virus Definitions (Intelligent Updater) line at the top of this write-up.

    Intelligent Updater virus definitions are available here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.
To restart in Safe mode:
All Windows 32-bit operating systems except Windows NT can be restarted in Safe mode. Read the document for your operating system.
To delete the worm files:
  1. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
  2. Run a full system scan.
  3. Delete all files that are detected as W32.Gibe@mm.
  4. Using Windows Explorer, delete the \Windows\02_N803.dat file.

To edit the registry:

CAUTION : We strongly recommend that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document How to back up the Windows registry for instructions.
  1. Click Start, and click Run. The Run dialog box appears.
  2. Type regedit and then click OK. The Registry Editor opens.
  3. Navigate to the key

  4. In the right pane, delete the following values:

    LoadDBackUp C:\Windows\BcTool.exe
    3Dfx Acc C:\Windows\GFXACC.exe
  5. Navigate to and delete the key

  6. Click Registry, and click Exit.

Writeup By: Gor Nazaryan