SilverPush has been around for a while but was recently reverse-engineered so that it could be investigated by anyone with an interest in their phones security.  It is software that is often bundled in advertisements or streamed media that takes advantage of your phones the far greater range of audio sensitivity and the fact that you can communicate information via audio signals.  This could allow an app to communicate with your phone without your knowledge, to collect data from your phone or even to provide contextual ads on your phone.

However as you can see from the list of apps which The Register links to, there is not much likelihood that you have an app which has SilverPush enabled installed on your phone and that is the real key.  If you do not have an app which is listening for audio signals on those frequencies then you will not suffer the effects of SilverPush.  The moral of the story is that your phones security starts with you, if you download random free apps and allow them full access to your phone then you should not be surprised by this sort of thing.

"SilverPush's software kit can be baked into apps, and is designed to pick up near-ultrasonic sounds embedded in, say, a TV, radio or web browser advert. These signals, in the range of 18kHz to 19.95kHz, are too high pitched for most humans to hear, but can be decoded by software."

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