You can read more about it at http://www.wired.com/news/infostruct...,57467,00.html
It's the most evil thing on the Internet, according to some of its victims. But it's not a virus, a scam or a raunchy porn site. It's a browser toolbar that some swear is doing "drive-by downloads" -- installing itself without users' permission -- then taking over their systems and making it impossible to uninstall. "When I find the bastards who programmed this thing I'd be happy to castrate them with a pair of dull pinking shears," fumed one of Xupiter's many unhappy victims in a newsgroup posting. Xupiter is an Internet Explorer toolbar program. Once active in a system, it periodically changes users' designated homepages to xupiter.com, redirects all searches to Xupiter's site, and blocks any attempts to restore the original browser settings. The program attempts to download updates each time an affected computer boots up, and has been blamed for causing system crashes. Several versions of Xupiter also appear to download other programs, such as gambling games, which later appear in pop-up windows. Some said that Xupiter has taken over their browsers. "Random words and characters now appear when I attempt to enter info on search sites or other forms. It's as if there's a ghost in my machine," New York resident Beth Vanesky said. Xupiter.com is registered to a company called Tempo Internet, in Gyongyos, Hungary. Calls and e-mails to Tempo were not returned. Xupiter offers an uninstall utility, but many said that it didn't work, and in some cases made things worse.