Steps:-
1) First of all download wire-shark and install it.
2) Go to Facebook or any other social media websites, Chat with your victim for 5 to 10 minutes. File sharing is better
3) Next open up wire-shark click on capture and then click on interfaces.
4) Next choose the appropriate interface and click on start.
5) Continue sniffing for around 10 minutes.
6) After 10 minutes stop the packet sniffing by going to the capture menu and clicking on Stop.
7) Next set the filter to HTTP.cookie contains dart at top left, This filter will search for all the HTTP cookies with the name dart, And dart as we know is the name of the Facebook authentication cookies
8) Next you’ll want to open up Firefox. You’ll need both Grease-monkey and the cookie injector script. Now open up Facebook.com and make sure that you are not logged in.
9) Press Alt C to bring up the cookie injector, Simply paste in the cookie value into it.
10) Now refresh your page and voila!! you are logged in to the victims Facebook account.
Download link of Wire-shark:-http://www.filehippo.com/download_wireshark/