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Category: Malware

Type: Backdoor

Aliases: Backdoor.Win32.IRCBot.et


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


Automatic action

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

Network Disinfection

For general instructions on disinfecting a local network infection, please see Eliminating A Local Network Outbreak.

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Technical Details

Backdoor:W32/IRCBot.ET is a variant of a bot that spreads by exploiting the known Plug and Play service (MS05-039) vulnerability. It is a packed PE executable file 51326 bytes long.

The bot was first found on August, 16th 2005.


When run, the worm copies under %SYSTEM% directory using the name 'windrg32.exe'. Then it adds the following registry entries to ensure that it is started when a user logs on or the system is restarted:

  • [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run] "winDrg32" = "windrg32.exe"

The worm scans for systems vulnerable to Microsoft Windows Plug and Play service (MS05-039) through TCP/445. Please see the following page for detailed information on the vulnerability: http://www.microsoft.com/technet/security/Bulletin/MS05-039.mspx

The following ports are used in attack:

  • Port 445:The worm scans for systems vulnerable to PnP exploit through this port
  • Port 29463: FTP server port on infected systems
  • Port 6667:The command shell port opened by the exploit code.

The worm tries to connect to IRC channel at predefined address. The attacker who knows channel password can instruct the bot to execute the following actions:

  • Disconnect/reconnect from the IRC channel
  • Request system information
  • Download and execute files
  • Remove worm from the system
  • Manipulate system security settings

IRCBot.ET also tries to uninstall some other malware and adware by deleting files and folders and removing registry keys. The worm tries to terminates the following processes:

  • botzor.exe (Net-Worm.Win32.Mytob.cd / Zotob.A)
  • CMESys.ex
  • csm.exe (Net-Worm.Win32.Mytob.cf / Zotob.B)
  • CxtPls.exe
  • NHUpdater.exe
  • pnpsrv.exe (Backdoor.Win32.Rbot.yk
  • qttask.exe
  • realsched.exe
  • ViewMgr.exe
  • winpnp.exe (Backdoor.Win32.Rbot.ym)
File System Changes

Removes these files:

  • %ProgramFiles%\180Solutions
  • %ProgramFiles%\180Solutions\*.exe
  • %ProgramFiles%\AutoUpdate
  • %ProgramFiles%\AutoUpdate\AutoUpdate.exe
  • %ProgramFiles%\Common Files\CMEII
  • %ProgramFiles%\Common Files\GMT
  • %ProgramFiles%\Common Files\GMT\GMT.exe
  • %ProgramFiles%\Common Files\WinTools
  • %ProgramFiles%\Common Files\WinTools\*.exe
  • %ProgramFiles%\CxtPls
  • %ProgramFiles%\EbatesMoeMoneyMaker
  • %ProgramFiles%\eZula
  • %ProgramFiles%\eZula\mmod.exe
  • %ProgramFiles%\Hotbar
  • %ProgramFiles%\Hotbar\*.exe
  • %ProgramFiles%\MyWay
  • %ProgramFiles%\MyWay\*.exe
  • %ProgramFiles%\MyWebSearch
  • %ProgramFiles%\MyWebSearch\*.exe
  • %ProgramFiles%\NavExcel
  • %ProgramFiles%\Toolbar
  • %ProgramFiles%\Toolbar\*.exe
  • %System%\botzor.exe
  • %System%\csm.exe
  • %System%\pnpsrv.exe
  • %System%\winpnp.exe
Registry Modifications

Deletes these values:

  • [HKCU\Software\Microsoft\Windows\Run] "180" "180ax" "Apropos" "AutoUpdater" "CMESys" "csm Win Updates" "Ebates" "EbatesMoeMoneyMaker" "eZmmod" "eZula" "Gator" "GatorDownloader" "Hotbar" "IBIS TB" "lgbibsn" "msbb" "MyWay" "MyWebSearch" "NavExcel" "QuickTime" "QuickTime Task" "Real" "saie" "sais" "TBPS" "TkBellExe" "Toolbar" "tov" "Trickler" "ViewMgr" "Viewpoint" "WeatherOnTray" "Windows PNP" "Windows PNP Server" "WINDOWS SYSTEM" "WinTools" "Zotob"