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Category: Malware

Type: Backdoor

Aliases: Backdoor.Win32.IRCBot.es


A remote administration utility that bypasses normal security mechanisms to secretly control a program, computer or network.


Automatic action

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

Special Removal Tool

F-Secure provides a special disinfection utility program to eliminate this malware infection. You can download this utility from our ftp or web sites:

  • ftp://ftp.f-secure.com/anti-virus/tools/f-bot.zip
  • http://www.f-secure.com/tools/f-bot.exe
  • ftp://ftp.f-secure.com/anti-virus/tools/f-bot.exe

Disinfection instructions can be found here:

  • ftp://ftp.f-secure.com/anti-virus/tools/f-bot.txt

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

Knowledge Base

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About the product

See the manual for your F-Secure product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details

Backdoor:W32/IRCBot.EX provides unauthorised access to an infected computer and also has the capability to spread to remote computers using the PnP exploit on port 445.

The backdoor's file is a PE executable file about 8 kilobytes long, packed with MEW file compressor and patched with PE_Patch.

This IRC-based backdoor-worm was found on August 15th, 2005 in Finland.


The backdoor has the ability to spread to remote computers using the PnP exploit on port 445. Please see the following page for detailed information on the vulnerability:

  • http://www.microsoft.com/technet/security/Bulletin/MS05-039.mspx

When the backdoor's file is activated on a computer, it copies its file to Windows System folder as MOUSEBM.EXE and then starts the copied file as a service named 'Mouse Button Monitor', described as follows: Enables a computer to maintain synchronization with a PS/2 pointing device. Stopping or disabling this service will result in system instability.

If the backdoor fails to start its service, it tries to inject its code into Explorer.exe process.


When active, the backdoor connects to one of the following servers on port 18067:

  • esxt.is-a-fag.net
  • esxt.legi0n.net

Then backdoor joins an IRC channel called '#p2' using the hardcoded password and creates a bot there. A remote hacker can control a backdoor via a bot that it creates in the '#p2' channel. A hacker can do any of the following:

  • Scan for vulnerable computers and spread to them using PnP exploit
  • Download and run files on an infected computer
  • Find files on local hard disks
  • Perform DDoS (Distributed Denial of Service) attack
  • Perform SYN and UDP flood

Date Created: -

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