Just take a picture!

In a movie-plot like scenario, where a biometric system is bypassed using restored fingerprint samples, Penn State researchers managed to identify the pass code patterns on two Android smartphones 68% of the time.

The researchers used photographs taken from smartphone touch screen surfaces under different lighting conditions and camera positions. The experimenting took place using two different scenarios -- the passive attacker, who operates from a distance, and the active attacker who has physical access to the device. In one experiment, the pattern was partially identifiable in 92% and fully in 68% of the cases. Even in the worst performing experiment, the pattern could be partially extracted in 37% of the setups and fully in 14% of them.

Source: ZDNet.