Win32/Gibe is a family of mass-mailing network worms that targets certain versions of Microsoft Windows. The worm spreads primarily by sending a copy of itself as an attachment to e-mail addresses found on the infected computer. It can also spread through writeable network shares, IRC channels, and peer-to-peer network file sharing.

What to do now

To detect and remove this threat and other malicious software that may be installed on your computer, run a full-system scan with an appropriate, up-to-date, security solution. The following Microsoft products detect and remove this threat:
For more information on antivirus software, see

Threat behavior

Win32/Gibe may take actions such as the following:
  • Display a message box with fabricated information. The message box may contain a Yes button and a No button. If the user clicks either button, the worm installs itself. If the user does not click a button, the worm might not install itself.
  • Check whether the worm previously set a registry value to indicate that the system was infected. If the registry value is set, the worm may immediately exit.
  • Drop multiple copies of itself with various names to locations such as the system folder, %windir%, and %temp%.
  • Modify the registry as follows:
    • Create one or more values in registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run 
      so that the worm runs each time Windows starts.
    • Modify the value in each of the following keys so that the worm runs each time a corresponding file runs: 
  • Drop a backdoor component that monitors a TCP port for commands from attackers.
  • Spread in the following ways:
    • By sending a copy of itself as an attachment to e-mail addresses gathered from the computer or remote servers. The worm runs when a user opens the attachment.
    • By copying itself to startup folders on writeable network shares. 
    • By transmission through an IRC channel.
    • By copying itself to the share folder of the Kazaa peer-to-peer file-sharing program.


There may be no readily apparent indications that your computer is infected by Win32/Gibe.


Take the following steps to help prevent infection on your computer:
  • Enable a firewall on your computer.
  • Get the latest computer updates for all your installed software.
  • Use up-to-date antivirus software.
  • Limit user privileges on the computer.
  • Use caution when opening attachments and accepting file transfers.
  • Use caution when clicking on links to webpages.
  • Avoid downloading pirated software.
  • Protect yourself against social engineering attacks.
  • Use strong passwords.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. It is important to install updates for all the software that is installed in your computer. These are usually available from vendor websites.
You can use the Automatic Updates feature in Windows to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
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, such as Microsoft Security Essentials, that is updated with the latest signature files. For more information, see
Limit user privileges on the computer
Starting with Windows Vista and Windows 7, Microsoft introduced User Account Control (UAC), which, when enabled, allowed users to run with least user privileges. This scenario limits the possibility of attacks by malware and other threats that require administrative privileges to run.
You can configure UAC in your computer to meet your preferences:
Use caution when opening attachments and accepting file transfers
Exercise caution with email and attachments received from unknown sources, or received unexpectedly from known sources. Use extreme caution when accepting file transfers from known or unknown sources.
Use caution when clicking on links to webpages
Exercise caution with links to webpages that you receive from unknown sources, especially if the links are to a webpage that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your computer simply by visiting a webpage with harmful content.
Avoid downloading pirated software
Threats may also be bundled with software and files that are available for download on various torrent sites. Downloading "cracked" or "pirated" software from these sites carries not only the risk of being infected with malware, but is also illegal. For more information, see 'The risks of obtaining and using pirated software'.
Protect yourself from social engineering attacks
While attackers may attempt to exploit vulnerabilities in hardware or software to compromise a computer, they also attempt to exploit vulnerabilities in human behavior to do the same. When an attacker attempts to take advantage of human behavior to persuade the affected user to perform an action of the attacker's choice, it is known as 'social engineering'. Essentially, social engineering is an attack against the human interface of the targeted computer. For more information, see 'What is social engineering?'.
Use strong passwords
Attackers may try to gain access to your Windows account by guessing your password. It is therefore important that you use a strong password – one that cannot be easily guessed by an attacker. A strong password is one that has at least eight characters, and combines letters, numbers, and symbols. For more information, see

Alert level: Severe
This entry was first published on: Sep 15, 2005
This entry was updated on: Apr 17, 2011

This threat is also detected as:
  • W32/Gibe@MM (McAfee)
  • W32.Gibe@mm (Symantec)
  • WORM_GIBE (Trend Micro)