The findings were presented at the Black Hat cyber security conference.
Researchers from the University of Massachusetts have created software which can crack your device password or PIN by analysing the video recorded through Google Glass.
Researchers claim that they can steal the passwords entered on a smartphone or tablet using video recorded through Google's face-mounted gadget and other video-capturing devices from a distance of over 140 feet and analysing it later.
The software uses a custom-coded video recognition algorithm which can track shadows from the finger taps while the password is being entered, letting the hacker know the keys that were used to unlock the device.
The researchers said that the positions of the keys in devices are always same and that makes the hacking process easier with the software.
There are tools available that can randomise the location of the keys and the researchers suggests users to use those tools to avoid such vulnerabilities.
The team tested the software on Google Glass, an iPhone 5 camera along with Logitech webcam and they succeeded in cracking the password with 90% accuracy.
UMass computer science professor Xinwen Fu said: "The major thing here is the angle.
"To make this attack successful the attacker must be able to adjust the angle to take a better video ... they see your finger, the password is stolen."
Google said that the Glass gives signals when it captures videos, hence it will alert the user who is targeted.