Which of the following is the least secure method to use for implementation?

An OT security practitioner wants to implement two-factor authentication (2FA).

Which of the following is the least secure method to use for implementation?
A . Out-of-band authentication (OOBA)
B. 2FA over Short Message Service (SMS)
C. Authenticator Apps for smartphones
D. Fast Identity Online (FIDO) Universal 2nd Factor (U2F) USB key

View Answer

Answer: B