https://arstechnica.com/information-technology/2017/05/theres-a-spike-in-android-apps-that-covertly-listen-for-inaudible-sounds-in-ads/ https://arstechnica.com/

https://arstechnica.com/information-technology/2017/05/theres-a-spike-in-android-apps-that-covertly-listen-for-inaudible-sounds-in-ads/ https://arstechnica.com/information-technology/2017/05/there... Be careful which apps you allow to use your phone's microphone.