Security Analysis of SMS as a Second Factor of Authentication

Abstract

Despite their popularity and ease of use, SMS-based authentication tokens are arguably one of the least secure forms of two-factor authentication. This does not imply, however, that it is an invalid method for securing an online account. The current security landscape is very different from that of two decades ago. Regardless of the critical nature of an online account or the individual who owns it, using a second form of authentication should always be the default option, regardless of the method chosen. In the wake of a large number of leaks and other intrusions, there are many username and password combinations out there in the wrong hands that make password spraying attacks cheap and easy to accomplish.