The
Yahoo logo is shown at the company's headquarters in Sunnyvale, Calif.
in this April 16, 2013 file photo. (Robert Galbraith/Reuters)
Two Internet security firms have reported that Yahoo's advertising
servers have been distributing malware to hundreds of thousands of users
over the last few days. The attack appears to be the work of malicious
parties who have hijacked Yahoo's advertising network for their own
ends.