Advertising - On the Web, ads can be a security hole - NYTimes.com

OVER the weekend, some visitors to the Web site of The New York Times received a nasty surprise. An unknown person or group sneaked a rogue advertisement onto the site’s pages.

The malicious ad took over the browsers of many people visiting the site, as their screens filled with an image that seemed to show a scan for computer viruses. The visitors were then told that they needed to buy antivirus software to fix a problem, but the software was more snake oil than a useful program...