In the (recent) past, online advertising was simply a nuisance, one that frustrated users but not much else. Today that’s changed, and not in a good way.
As discovered by Malwarebytes Unpacked, the HuffingtonPost website, for example, was recently attacked through one of their major ad networks, the criminals exposing a vulnerability and the Flash player used on the site to attack it with “malvertising.”
As you might be able to guess from the name, malvertising is advertising that carries malware hidden inside, created by hackers for a variety of criminal intentions. It’s difficult to detect because it piggybacks in advertising created by trusted companies, and it’s even more insidious because the trust factor that users have for advertising is high.
For instance, one recent malvertising attack was pulled off through the Merchanta ad network, which has direct ties to Google’s DoubleClick and roughly 30 billion monthly impressions in the US alone.
Hackers managed to get in through the back door using bidable.com, a real-time bidding company. The company itself wasn’t at fault but instead one of their clients, showing how difficult it is to detect and track these new type of attacks.
It’s quite ingenious actually. Hackers submit a clean advertising link at first and go through the chain of quality assurance. Once they’ve been approved, and right before the advertisement actually goes out to the Internet, they replace their clean version with malvertising. Since they’ve already been through the checks, and since the ad network doesn’t want to lose a client, their malicious ad gets through.
For end-users it’s just another reason to have ad blockers installed on their computers, and another reason to hate online advertising in general.