<https://cacm.acm.org/magazines/2020/12/248798-security-analysis-of-sms-as-a-...> [...] This article provides some insight into the security challenges of SMS-based multifactor authentication: mainly cellular security deficiencies, exploits in the SS7 (Signaling System No. 7) protocol, and the dangerously simple yet highly efficient fraud method known as SIM (subscriber identity module) swapping. Based on these insights, readers can gauge whether SMS tokens should be used for their online accounts. This article is not an actual analysis of multifactor authentication methods and what can be considered a second (or third, fourth, and so on) factor of authentication; for such a discussion, the author recommends reading security expert Troy Hunt's report on the topic.^9 <https://cacm.acm.org/magazines/2020/12/248798-security-analysis-of-sms-as-a-...> [...]