Malicious ads are nothing new, but after a few years of dealing with them, most ad networks are pretty good at blocking the obvious ones. The hackers behind recent attacks came up with an interesting new twist, though.
According to security firm Trustwave, the hackers found the domains of legitimate online marketing companies that had just expired and bought them. They used those domains to appear as valid businesses and purchase ad space on a huge number of ad networks, including Google's DoubleClick, Adnxs, Rubicon, AOL, AppNexus and Taggify.
Even sneakier, the ads had code that prevented them from attacking computers that had certain security research tools and security programs installed. That kept the security community from picking up on the attack right away and alerting the ad networks.