Firefox has the ability to save usernames and passwords for easy access later. It’s a handy little feature but it does pose a possible problem. If someone else were to use your computer, or steal your profile folder, they’d be able to access all your accounts. That’s a bit scary. However, you can set a master password in Firefox and protect yourself.

A master password will allow anyone to use your browser, but, if they came across a page that had a saved username/password, Firefox will ask for the master password before auto populating the username and password fields. If the user doesn’t know it, they can hit cancel and continue to use the site without access to any of your accounts.