Yahoo! Messenger virus

Researchers at FaceTime Security Labs have identified a new threat -- yhoo32.explr, a self-propagating worm that installs "Safety Browser" and hijacks the Internet Explorer homepage, leading users to a site that puts spyware on their PCs, said the security research firm. 

Moreover, the worm spreads the infection to all contacts within an individual's messenger service by sending a Web site link that loads a command file onto the user's PC and installs the Safety Browser.

This is the first recorded incidence of malware installing its own Web browser on a PC without the user's permission, according to FaceTime Security Labs.

"This is one of oddest and more insidious pieces of malware we have encountered in years," said Tyler Wells, senior director of research at FaceTime Security Labs. "This is the first instance of a complete web browser hijack without the user's awareness. Similar 'rogue' browsers, such as 'Yapbrowser,' have demonstrated the potential for serious damage by directing end-users to potentially illegal or illicit material. 'Rogue' browsers seem to be the hot new thing among hackers."