"Advertising networks have served malware onto the computers of unwitting news readers over and over in the past couple years. Ads on Forbes for example, attacked their readers in January, right after the magazine forced readers to disable ad-blocking software to view its popular annual “30 Under 30” feature. As Engadget reported, "visitors were immediately served with pop-under mal ware, primed to infect their computers, and likely silently steal passwords, personal data and banking information.” It wasn’t the first time this had happened at Forbes, either. And it’s not just in the US. A couple months ago, almost every major news site in the Netherlands served malware through its ads to its users.
"You can bet this problem is only going to get worse. According to a 2015 study, malware served by advertising networks tripled between June 2015 and February 2015. So the longer people wait to install an ad blocker, the more vulnerable they become."