Malwarebytes has warned users of the UnfriendAlert app asking users to login with their Facebook credentials to activate unfriends monitoring and alert service for your Facebook profile. Users are recommended to uninstall the app from your computer and change your Facebook password as soon as possible. The app is also classified as potentially unwanted program (PUP) which often displays unwanted advertisements and deceptively installs other malicious software and free apps when visiting some web pages in your Chrome, Firefox and Internet Explorer, making you fail to block them.
Source: https://thehackernews.com/2015/06/facebook-password-hacking.html