Page 46 - FCW, September/October 2019

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Fighting digital eavesdropping with audio masking
On-device audio masking can limit the exposure of users’ confidential conversations without crippling the power of smart devices
BY MIKE FONG
Thanks in no small part to a barrage of news stories about smartphone spyware and misbehaving smart devices, there’s a growing awareness that the cameras and microphones
in our digital companions can be hijacked by sophisticated threat actors to remotely spy and eavesdrop on users.
But while it’s relatively straight- forward for users of these devices
to prevent illicit image capture by blocking built-in cameras, the com- plexities associated with blocking sound preclude a simple equivalent for microphones. To solve this gap
in protection, sophisticated products have started to emerge that add noise
near a device’s microphones to mask sound in the vicinity of the device.
Why audio data matters
Before discussing the ins and outs of preventing illicit audio capture, it’s helpful to look at why threat actors seek audio data in the first place.
Sensitive and confidential conver- sations are digital eavesdropping’s version of gold because the informa- tion revealed in those discussions
is often too sensitive or too fresh to be written down or recorded and therefore is unavailable through other modes of hacking. Think of an intelligence service learning about an adversary’s strategic moves well in
advance or a corporate spy learning about a competitor’s product devel- opment while it’s still in the early stages.
But it’s not just long, uninterrupted sequences of dialogue that can be valuable to an eavesdropper. Random audio snippets, for example, can be pieced together to draw important conclusions, especially when the audio is accompanied with other data points.
After the recordings of an Amazon Alexa user in Germany were mistak- enly sent to another user, a neutral party listening to the audio files was able “to piece together a detailed picture of the customer concerned
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