Trojan horse programs dressed up like video decoders, or codecs, have
become a popular way to attempt to infect the computers of unwary Web
surfers.
Research by antispyware firm Sunbelt Software found that a number of sites hosted by blog service provider Blogger,
a subsidiary of Google, contained fake video files that, if clicked on
by a visitor, would prompt the victim to download and install a video
helper application. In reality, the application is a Trojan horse
program designed to infect the victim's PC, CEO Alex Eckelberry stated
in the blog post.
http://www.securityfocus.com/brief/650