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Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.


Threat LevelHigh threatDamageSevereDistributionNot widespread
Common name:Zotob.A
Technical name:W32/Zotob.A.worm!CME-243
Threat level:Medium
Alias:CME-243, W32/Bozor.A.worm, I-Worm/Mytob.LY, Malware.n, Mytob,, W32.IRCBot, W32.Zotob.A, W32.Zotob.B, W32/Zotob.A, W32/Zotob.A-net, W32/Zotob.worm, W32/Zotob.worm.b, W32/Zotob-A, Win32.HLLM.MyDoom, Win32.Worm.Zotob.A, Win32.Zotob.A, Win32/Mytob, Win32/Zotob.A, Win32/Zotob.A!Worm, Worm.IRCBot.DL, Worm.Zotob.A, WORM_MYTOB.JS, WORM_ZOTOB.A, WORM_ZOTOB.B, Zotob, Zotob.A, Zotob.B

It connects to an IRC server in order to receive remote control commands and prevents users from accessing several web pages. It spreads across the Internet by exploiting the Plug and Play vulnerability.

Affected platforms:

Windows 2003/XP/2000/NT/ME/98

First detected on:Aug. 14, 2005
Detection updated on:Jan. 14, 2006
Proactive protection:
Yes, using TruPrevent Technologies
Repair utility:Panda QuickRemover

Brief Description 


Zotob.A is a worm that connects to an IRC server in order to receive remote control commands, such as delete, download and run files.

Aditionally, it prevents users from accessing certain web pages, mostly belonging to antivirus companies.

Zotob.A spreads across the Internet, by exploiting the Plug and Play vulnerability.


If you have a Windows 2003/XP/2000 computer, it is highly recommendable to download the security patch for the Plug and Play vulnerability from the Microsoft website.

Visible Symptoms 


Zotob.A is difficult to recognize, as it does not display any messages or warnings that indicate it has reached the computer.