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Category: Malware

Type: -

Aliases: Bozori.A, Net-Worm.Win32.Bozori.a, WORM_RBOT.CBQ, W32.Zotob.E, W32/Tpbot-A


This IRC-based backdoor-worm was found on August 16th, 2005. The backdoor provides unauthorised access to an infected computer and also has the capability to spread to remote computers using the PNP exploit.


Automatic action

Once detected, the F-Secure security product will automatically handle a harmful program or file by either deleting or renaming it.

Eliminating a Local Network Outbreak

If the infection is in a local network, please follow the instructions on this webpage:

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About the product

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Submit a sample

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Technical Details

The executable is a file of around 10KB.

When the backdoor's file is activated on a computer, it copies its file to Windows System folder as wintbp.exe and then starts the copied file. Then it adds the following registry entries to ensure that it is started when a user logs on or the system is restarted:

"Wintbp" = "wintbp.exe"

The backdoor connects to IRC server, joins an IRC channel called '#tbp' and creates a bot there.

The backdoor has the ability to spread to remote computers using the PNP exploit on port 445. If the attack is successful a shell (cmd.exe) is started on port 8594. Through the shell port, the worm sends a tftp script which instructs the remote computer to download and execute the worm from the attacker computer using built-in TFTP server listening on port 69.

Here's the summary of the ports used in attack:

  • Port 445- The worm scans for systems vulnerable to PnP exploit through this port
  • Port 69- TFTP server port on infected systems
  • Port 8594- The command shell port opened by the exploit code

Please see the following page for detailed information on the vulnerability: