A group of researchers from Newcastle University demonstrated that hackers can potentially guess PINs and passwords entered by the owner of the mobile device while authenticating itself on a website or an app. The technique devised by the experts has a surprising degree of accuracy, experts can monitor the angle and motion of the phone while the owner is typing a secret code. Mobile phones dont restrict websites and apps from accessing sensors data. Researchers were able to guess four-digit PINs on the first try with 74% accuracy and on the fifth try with 100% accuracy.”]
Source: https://securityaffairs.co/wordpress/57970/hacking/stealing-pin-phone-sensors.html