According to recent research in Sweden and UK, hackers are now be able to steal the unlock pattern of your Android phone. With the help of speakers and microphones, the sonar will be able to pick up the movements of the fingers against the screen.
This technique is known as SonarSnoop. It is the malicious version of FingerIO. You should not rely on unlock patterns for protecting your phone. Nowadays, mobile phones come with fingerprint sensors which are considered to be a lot more secured than other pattern unlocks. Also you need to make sure that your Android runs on the latest version.
For the purpose of making the SonarSnoop work you will first have to install a malware app. Other kinds of devices are also applicable that have microphones and speakers.