With its millions of users, the world’s most popular social network has become a perfect target for hackers exploiting such a dense concentration of potential victims. Apart from phishing attacks or spam, which are now easily recognized by many Internet users, hackers are employing new methods, which for the moment at least, are proving to be successful. What to do if your Facebook profile has been hacked
Step 1: Firstly, remove all permissions that have been given to the malicious application. This is a simple process: from Account > Application settings in the top-right corner of your Facebook profile. This ensures that the application will not continue to have access to your profile once the password is changed.
Step 2: Change the login password! To keep your identity safe, it is advisable to change your password and the user name (it’s a good idea to do this from time to time anyway). This is also easy: Go to Account > and Account Settings in the menu in the top left corner of your Facebook profile. It is also advisable to use strong passwords that cannot easily be guessed.
(Source: Panda Security)