Malvertising
Also known as malicious advertising, occurs when unwanted malicious software is installed through internet advertisements. Social media networks are common websites where this type of attack occur; however, any website with third party content can have malicious advertising.
Source URL:
http://isc.sans.edu/diary.html?storyid=3727
http://www.readwriteweb.com/enterprise/2010/09/what-you-need-to-know-about-ma.php