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Category: Malware

Type: -

Aliases: Backdoor.Win32.IRCBot.et, W32.Zotob.D, W32/Dogbot-A


A new variant of a bot spreading the Plug and Play service (MS05-039) vulnerability has been found on August, 16th 2005.


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

The worm is a packed PE executable file 51326 bytes long.

Installation to system

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:

"winDrg32" = "windrg32.exe"
Spreading using Plug and Play service vulnerability

The worm scans for systems vulnerable to Microsoft Windows Plug and Play service (MS05-039) through TCP/445.

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 29463- FTP server port on infected systems
  • Port 6667- The command shell port opened by the exploit code

Please see the following page for detailed information on the vulnerability: https://www.microsoft.com/technet/security/Bulletin/MS05-039.mspx

Bot functionality

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
Other details

IRCBot.et 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)

csm.exe		(Net-Worm.Win32.Mytob.cf / Zotob.B)



pnpsrv.exe		(Backdoor.Win32.Rbot.yk)



winpnp.exe		(Backdoor.Win32.Rbot.ym)

It tries to delete the following registry values:


"csm Win Updates"
"QuickTime Task"
"Windows PNP"
"Windows PNP Server"

The worm also tries to delete the following files and folders:





%ProgramFiles%\Common Files\CMEII

%ProgramFiles%\Common Files\GMT

%ProgramFiles%\Common Files\GMT\GMT.exe

%ProgramFiles%\Common Files\WinTools

%ProgramFiles%\Common Files\WinTools\*.exe