What Is Trojan Vundo?

Vundo is a malicious program for Windows system. Here are some short descriptions of Vundo I found on the Internet:

1. From www.spynomore.com/articles/vundo-trojan-specifics-and-removal.php:
Vundo (also known as VirtuMonde and VirtuMundo) is a malicious software application that combines both adware and trojan characteristics.
Vundo is wide spread today and is probably one of the hardest programs to get rid of. Once installed, Vundo downloads and displays pop-up advertisements that often promote questionable computer-enhancement programs or fake anti-virus or anti-spyware utilities. Lately, Vundo has been advertising several rogue programs called WinFixer2005, WinAntiVirus Pro 2006, WinAntiSpyware and RazeSpyware.

2. From vil.nai.com/vil/content/v_127690.htm:
This is a trojan detection. Unlike viruses, trojans do not self-replicate. They are spread manually, often under the premise that they are beneficial or wanted. The most common installation methods involve system or security exploitation, and unsuspecting users manually executing unknown programs. Distribution channels include email, malicious or hacked web pages, Internet Relay Chat (IRC), peer-to-peer networks, etc.

3. From en.wikipedia.org/wiki/Vundo:
The Vundo trojan is a trojan horse that may cause popups advertising rogue antispyware programs. It infects victims' computers by exploiting a vulnerability in Sun Java 1.4 and earlier versions. Many of the popups advertise a program called Sysprotect.