The amount of malicious adware more than doubled last year as cyber criminals adjust their strategy in the wake of better security elsewhere, according to a new malware report from G Data Software.

In the second half of 2014, adware accounted for 31.4 percent of all new malware signatures, up from 14.1 percent during the first half of the year.

This total includes adware products that infect existing ads to cause malicious downloads, intrusive popup ads, and malware that injects new ads into websites.

Adware is now the second most-common malware category, having passed downloaders for the first time last year. It is quickly catching up to Trojans, which are still, by a slim margin, in first place.

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