Mozilla announced the rollout of its two-step verification program for all Firefox Accounts designed without support for SMS-based codes.
The feature is designed to work with the support of three authentication mobile apps: Google Authenticator, Duo Mobile and Authy 2-Factor Authentication and it is unclear of the feature will be expanded to work with other applications.
The new feature most likely doesn't support SMS based codes because as criminals are able to exploit known weaknesses in the SS7 cellphone network to intercept text messages.
“Two-step authentication adds extra security by making it harder for someone else to log into your account, especially if they steal your password,” Firefox said in a recent blog
Users looking to enable the new features will need to first download one of the authentication apps, then follow a set of direction in their Firefox browser to enable the feature after which, when a user attempts to lo into their Firefox account, they will need to generate a one-time passcode using their verified account on their authentication mobile app after entering in their username and password.