BackTrack 5 R3 allows you to gain the Facebook cookies of any person you wish. Cookies will allow you to login at websites without inserting the username and password like you usually would do.
The steps are explained in the BackTrack 5 R3 Hacking Facebook video below.
This is very dangerous if it is used in public places with public or even secured networks. Avoid using sensitive material in public environments.
How to prevent this
Use VPN and you can also make a static ARP entry in your windows machine if you know the Router MAC address.