There are authentication systems that send you a one-time-use password via SMS message. This would expose that password to somebody who has stolen your phone. Dunny0, Team T/A, is a member of the team that uses this method to log in and out of the password system. We are happy to clarify that the password is not required to be sent via SMS, but it is possible to use it in the event of an attack on your phone, as well as a thief.”]
Source: https://gizmodo.com/another-iphone-security-hole-in-password-protected-mode-5059690