should be selective in downloading about the apps they want to download
say this technique can even be used to de-anonymize Tor users.
Let’s see what
this technique is about:
An increasing number of Android applications are
attempting to track users without their knowledge, according to a new report.
Many app development Companies have now started hiding
“beacons”, beacons--that are ultrasonic audio signals not audible to humans,--
in their adverts, in order to track devices and learn more about their owners
from some past recent years.
Electronic devices equipped with microphones can register
these sounds, allowing advertisers to uncover their location and work out what
kind of ads their owners watch on TV and which other devices they own.
The technique can even be used to de-anonymize Tor users.
A report from researchers at Technische Universität
Braunschweig in Germany, stated “Throughout our empirical study, we confirm
that audio beacons can be embedded in sound, such that mobile devices spot them
with high accuracy while humans do not perceive consciously the ultrasonic
They found that, while six apps were known to be using
ultrasound cross-device tracking technology in April 2015, this number grew to
39 by December 2015, and has now increased to 234.
The study hasn’t named any specific programs, but says
that several have millions of downloads and “are part of reputable companies”,
including McDonald’s and Krispy Kreme.
“They embed these beacons in the ultrasonic frequency
range between 18 and 20 kHz of audio content and detect them with regular
mobile applications using the device’s microphone,” the research adds.
Since consumers need to have the apps open in order for
advertisers to use them for tracking purposes, the privacy threat isn’t quite
as worrying as it could be.
However, the researchers believe it could grow into a
serious issue "in the near future”.
As ever, users should be selective about the apps they
You should be able to analyze, why an app is asking for any
particular permissions, such as access to your camera or microphone, think
twice about installing it.