Is your browser mining bitcoin? ‘Malvertisements’ are hijacking Google Ads

“Attackers abused Google’s DoubleClick, which develops and provides internet ad serving services, for traffic distribution. Data from the Trend Micro Smart Protection Network shows affected countries include Japan, France, Taiwan, Italy, and Spain. We have already disclosed our findings to Google,” Trend Micro reports.

As malware goes, it’s actually pretty clever — if also sinister and awful. It operates two separate scripts, one a coinhive cryptocurrency miner, the other a private web miner. Which one it will use is determined by a random number generator. When either one kicks in, it would use 80 percent of the affected computer’s CPU resources for the purposes of mining cryptocurrency.

“The affected webpage will show the legitimate advertisement while the two web miners covertly perform their task. We speculate that the attackers’ use of these advertisements on legitimate websites is a ploy to target a larger number of users, in comparison to only that of compromised devices,” Trend Micro reports.

Trend Micro goes on to report that the number of incidents of these malvertisements has gone down since January 24, so we might be in the clear. Still, it might be a good idea to make sure your security apps are all up to date — and make sure your browser has its latest security patches. Chances are Google will get the exploit under control quickly, but there are some countermeasures you can implement in the meantime.

“Blocking JavaScript-based applications from running on browsers can prevent coinhive miners from using CPU resources. Regularly patching and updating software — especially web browsers –can mitigate the impact of cryptocurrency malware and other threats that exploit system vulnerabilities,” Trend Micro recommends.

All right, so how can you protect yourselves from this exploit while Google gets it sorted out? Turns out there are a couple things you can do. First, make sure your browser is up to date. You can do that by heading to your preferences and checking for updates in most modern browsers like Chrome and Firefox. Second, run an adblocker on any site that you feel a little uncomfortable about. Lastly, you can always disable JavaScript entirely, but doing so will break a lot of websites and it’s only a good idea if you’re very worried about your security.