Users of popular file-sharing applications may unknowingly be sharing more than just their collections of audio files. A Trojan horse program masquerading as an advertising application was included with recent versions of programs BearShare, LimeWire, Kazaa and Grokster. The Trojan, dubbed "W32.Dlder.Trojan" by antiviral companies, is contained within an application called "ClickTillUWin" which promises users a chance to win prizes.
According to antiviral firm F-Secure, Dlder tracks URLs that users visit and posts them to a website. F-Secure reported that the Trojan also opens a security hole on infected systems by downloading and activating executable files. "We were told that this installer just created the icons and shortcuts for the ClickTillUWin promotion," Greg Bildson, chief technical officer at Limewire, said in an e-mail. "We rely on Cydoor to deal with our ad deals and bundled software. We assumed that they did their homework on this package but that does not seem to be the case," said Bildson. <snip> http://wired.com/news/privacy/0,1848,49430,00.html
