Have you visited amazon.com, ads.yahoo.com, www.winrar.com, youtube.com, or any of the 74 domains listed below lately? If the answer is yes, then you may have been a victim to the “Kyle and Stan” Malvertising Network that distributes sophisticated, mutating malware for Windows and even Macs.
more here.............http://blogs.cisco.com/security/kyle-and-stan/
more here.............http://blogs.cisco.com/security/kyle-and-stan/