Google is dedicated to continuously improving the security of Google accounts, Google have introduced a feature to keep user account safe from hijackers, even if they have your username and password. Now when Google detect a suspicious login, users will be prompted to verify their identity by entering their phone number. Users who have not set up their phone number will be prompted to do so.
For example, if we detect a suspicious login Google might send an SMS with a verification code to the user’s phone and ask them to enter this code before Google grant access to their account. This drastically reduces the chances of an unauthorized person accessing the account because they would have to get a hold of the user’s phone as well as the username and password.
users can skip entering their phone number, but may be asked to add their phone number again at a later date. Google will use that phone number to verify their identity upon the next suspicious login. When a user verifies their identity, the alert is dismissed.
Note: This feature only impacts web logins for users who do not have 2-step verification enabled and are not using SSO to login.
Get more information.
