Threat description



This IRC-based backdoor-worm was found on August 17th, 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

Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.

More scanning & removal options

More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details

The executable is a file of around 10KB.

Installation to system

When the backdoor's file is activated on a computer, it copies its file to Windows System folder as 'wintbpx.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:

"Wintbpx" = "wintbpx.exe"
Spreading using PnP exploit

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 8563. 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 8563- The command shell port opened by the exploit code

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

Terminating processes

The backdoor tries to terminate and delete the files of the following processes:

wintbp.exe		(Net-Worm.Win32.Bozori.a)		[uses MS05-039 exploit]
winpnp.exe		(Backdoor.Win32.Rbot.ym)		[uses MS05-039 exploit]
mousebm.exe		(		[uses MS05-039 exploit]
csm.exe		( / Zotob.B)	[uses MS05-039 exploit]
botzor.exe		( / Zotob.A)	[uses MS05-039 exploit]
pnpsrv.exe		(Backdoor.Win32.Rbot.yk)		[uses MS05-039 exploit]
svnlitup32.exe		(Backdoor.Win32.SdBot.yx)		[uses MS05-039 exploit]
upnp.exe		(Backdoor.Win32.Codbot.ab)		[doesn't use MS05-039 exploit]
Bot functionality

The backdoor connects to IRC server, joins an IRC channel called '#tbp' and creates a bot there. The attacker can instruct the bot to execute the following actions:

Exit bot
Remove bot
Download and execute files from the Internet

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