This way they find out the unlock pattern of the mobile phone with sounds

SonarSnoop turns the smartphone into a sonar through the speaker and microphone

Pin or unlock pattern? Both have an important level of security and are used indifferently, but now two universities have discovered a vulnerability that makes the speakers and the mobile microphone the perfect allies to decipher the unlock patterns of Android devices.

This is the research of Swedish and British academics who focus on sound waves to track the position of a finger on the screen. The technique is known as SonarSnoop.

This tool emits sound waves through the microphone and speakers at inaudible frequencies (between 18 kHz and 20 kHz). The research work, published last week, details the tests conducted on a Samsung Galaxy S4 with Android 5.0.1.

Researchers at the University of Lancaster in the United Kingdom and Linköping University in Sweden explain that the system was able to reduce the number of possible unblocking patterns by 70% with the data obtained with SonarSnoop.

The idea is taken from the famous sonar that the submarines assemble to establish their location. In recent years, academics have explored the idea of ​​using smart phone sensors such as accelerometers, gyroscopes and proximity sensors to record and steal PINs and unlock smartphone patterns, however these tools are now being used for the first time to steal private keys. .

SonarSnoop is "applicable to many other types of computing devices and physical environments where microphones and loudspeakers are available," the researchers note.