1. /
  2. Security Response/
  3. W32.Zotob.E


Risk Level 3: Moderate

August 16, 2005
February 13, 2007 12:43:29 PM
Also Known As:
CME-540, Win32/Zotob.E!Worm [Computer A, Bozori.A [F-Secure], Net-Worm.Win32.Bozori.a [Kaspe, W32/IRCbot.worm!MS05-039 [McAf, W32/Tpbot-A [Sophos], WORM_ZOTOB.E [Trend Micro], W32/Bozori.A [Norman]
Systems Affected:
Windows 2000

W32.Zotob.E is a worm that opens a back door and exploits the Microsoft Windows Plug and Play Buffer Overflow Vulnerability (described in Microsoft Security Bulletin MS05-039) on TCP port 445.

  • It has been reported that computers targeted by W32.Zotob.E may become unstable during execution of the exploit code. This may result in the termination of the services.exe process, which causes the targeted computer to shutdown.
  • Virus definitions version 70816y (extended version 8/16/2005 rev. 25) or greater are required to detect this risk.
  • Customers running the lastest versions of Norton Internet Security, Norton AntiVirus, or Symantec AntiVirus Corporate Edition can make use of the product's automated removal functionality to remove this risk.
  • While computers running Windows 95/98/Me/NT4/XP operating systems cannot be infected remotely, it is possible they could be infected if W32.Zotob.E is executed locally (although this is an unlikely occurrence). Vulnerable Windows 2000 computers could then be infected by the compromised computer.

Antivirus Protection Dates

  • Initial Rapid Release version August 16, 2005
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version August 16, 2005
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date August 16, 2005
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Threat Assessment


  • Wild Level: Medium
  • Number of Infections: 0 - 49
  • Number of Sites: More than 10
  • Geographical Distribution: Low
  • Threat Containment: Easy
  • Removal: Moderate


  • Damage Level: Medium


  • Distribution Level: High
Note: On May 14, 2015, modifications will be made to the threat write-ups to streamline the content. The Threat Assessment section will no longer be published as this section is no longer relevant to today's threat landscape. The Risk Level will continue to be the main threat risk assessment indicator.
Writeup By: Maryl Magee

Search Threats

Search by name
Example: W32.Beagle.AG@mm
STAR Antimalware Protection Technologies
Internet Security Threat Report