Google Removes 300 Apps Used to Launch DDoS Attacks From Play Store

Kate Conger, writing for Gizmodo:

Google has removed roughly 300 apps from its Play Store after security researchers from several internet infrastructure companies discovered that the seemingly harmless apps—offering video players and ringtones, among other features—were secretly hijacking Android devices to provide traffic for large-scale distributed denial of service (DDoS) attacks.

How many more have yet to be discovered?