There is an application that secretly picks up ultrasonic waves and tracks users, what measures can the user take?

The system which tracks (traces) while not knowing the movement and preference of the user by using a microphone which is definitely installed in all smartphones and receiving a special ultrasonic signal is spread widely It is.

Hundreds of Apps Using Ultrasonic Signals to Silently Track Smartphone Users
http://thehackernews.com/2017/05/ultrasonic-tracking-signals-apps.html

This mechanism is used by some marketing companies and advertisement-related companies, and is called "cross device tracking" that can track the behavior of a specific user by using multiple devices together. For example, when an advertisement of a television or a website is displayed, by issuing a high frequency signal "audio / beacon" which can not be heard by the human ear, and causing it to be picked up by a microphone such as a smartphone, the user using the terminal It will be possible to identify what kind of advertisement or page you are currently viewing.

This information makes it possible to deliver information and advertisements to users on a pinpoint, and for advertisers it is something I want as much as to get out of my throat. However, because it is also a technology that approaches very close to the identification of individuals, there are also views that view problems from the viewpoint of privacy. A symposium on security and privacy held at the end of April 2017IEEE European Symposium on Security and Privacy 2017"Said that 234 Android applications were requested to approve access to microphone to enable tracking using ultrasound beaconsreport(PDF) has been announced, as well as the fact that the equipment that generates ultrasound beacon was installed at the entrance of the store at 4 of the 35 shops in Germany that the investigation team visited.


According to the survey team, three types of SDK called "SilverPush" "Lisnr" "Shopkick" are used to realize audio beacons, SilverPush uses multiple devices to track user tracking, Lisnr and Shopkick It is tracking position information. In addition, when I investigated millions of Android applications, it seems that the fact that SilverPush SDK is used the most is revealed.

Cross device tracking technology itself is legitimate, but there are serious concerns about privacy. Even if the terminal is not connected to a communication network or Wi-Fi (= quarantined state), the fact that you are tracking whereabouts and actions just by using a microphone is a user's desire to keep privacy There is a fear that it is contrary to intention.

In fact, to ensure confidentiality of the communication pathTorDemonstrated that demonstrating that users using ultrasound beacons from advertisements will use the cross device tracking technology to clarify the user's location and IP to advertisers who use it.

Among the information that Mr. Edward Snowden revealed has also been made clear that the intelligence agencies in the United States had indexed travelers' travel routes from abroad based on the MAC address of the terminal and similar attempts It can be said that the possibility of being realized by using audio beacons exists quite a bit.

Spying agencies tracking your location by capturing MAC address of your devices


It is a mechanism of audio / beacon where there is a possibility that your actions may be tracked while you do not notice, but the simple way to prevent this is to "restrict the use of microphones". Some applications include using microphones like LINE, Skype, and map applications, but if you are asking for unnatural microphone usage rights despite being a fashion related application, for example There is also.

For Android devices, go to "Settings" → "Privacy and safety" → "Permissions of application" → "Mike" and manage the use of the microphone for each application, or "Settings" → "Application" → "Application management" Go ahead and check the usage of the microphone from the "privilege" of each application to be displayed.

For iOS, you can make settings for each application from "Settings" → "Privacy" → "Mike".