Malvertising Could Rival Exploit Kits

As the rate with which cyber criminals are gaming the ad network ecosystem to disseminate malware via malicious ads keeps snowballing, there may come a time where malvertising becomes top dog in the distribution of exploits.

"From our investigation we conclude that ad networks could be leveraged to aid or even substitute for current exploit kits," wrote researchers from Bromium in a new report released today at VirusBulletin looking at malicious ads, particularly those leveraging Flash. "Loose security policies, high prevalence, and powerful scripting capabilities make it a viable tool for malware distribution."

According to lead author of the report, Rahul Kashyap, chief security architect, Bromium, malvertising is particularly difficult for security ops personnel to deal with on a day-to-day basis due to the way that bad guys use embedded ad networks to serve up malicious content on otherwise reputable sites. Most blocking technology is not equipped to deal with this paradigm.

"It's a big challenge because how do you blacklist YouTube? How do you blacklist CNN? How do you deal with this," Kashyap says. "The attackers are actually buying ads and putting money into the system, they're highly motivated and they're not going to go away empty handed."

Bromium's conclusions are the latest in a growing stream of research pointing to the mounting problem of malvertising, including several additional alarming warnings out this week by Cisco and Invincea.

Cisco followed up on reports earlier this month about the Kyle and Stan malvertising network to report that its researchers had found that the network could be much bigger than they first estimated. Initially thought to be responsible for putting malicious ads on over 70 domains, including large sites like amazon.com, ads.yahoo.com, and youtube.com, Kyle and Stan was found by Cisco to have nine times as much reach online.

"As it turns out, this was just the tip of the iceberg," says Armin Pelkmann, threat researcher for Cisco.

Meanwhile, Invincea reported this week that Trade2win, a website that hosts the largest online forum for day traders, and TheBlaze.com, a conservative site run by Glenn Beck, are both currently serving up malvertising. This is the latest in a long list of groundbreaking work by the advertising industry-focused security company into the methods and techniques used against ad networks and the sites that depend upon them. This is actually the second offense for TheBlaze.com, which in July was found by Invincea to be serving up Kryptik drive-by exploits via malicious ads.