SO as you can probably tell from the title, this will be a small tutorial on how to get the password for android devices, specifically if it has a gesture password (see image left of here) For this demonstration I was getting the password for my HTC sensation, using the latest version of Debian.
For this to work you need to be able to access the /data/system/gesture.key file on the target device, This is done either with ADB or through a JTAG hardware interface. For this demonstration I'll be using ADB.
This is for educational purposes only, you should only do this on your own devices or with the owners permission.
So lets get started. There are a few programs you will need if you don't have them already:
$ apt-get installandroid-tools-adb unrar wget
Firstly check that ADB is working, and that there is only 1 device. If you have more than one device then you will need to remember the device ID and modify the commands accordingly.
$ adb devices
List of devices attached
This command will pull down the gesture.key file onto your local system.
$ adb pull /data/system/gesture.key
0 KB/s(20 bytes in0.046s)
Now download the rainbow table of all the possible codes and correlating pins and unrar it