A security hole in the Facebook app discovered by Gareth Wright, an app developer based in the U.K., can be used to steal information about you, including your login credentials.
The problem? The native Facebook app does not encrypt the login information. This means that a malicious app would be able to steal that information, and in turn, steal your Facebook account. If you use an Android smartphone/tablet or an Apple iPhone/iPad, you are vulnerable to this attack.
There is not much that can be done to prevent this at this point except to be careful of the apps you install on your phone. Install some form of security that validates whether an app is legitimate or not.