More online services than ever now offer two-step authentication requiring customers to complete a login using their phone or other mobile device after supplying a username and password. With so many services relying on your mobile for that second factor, there has never been more riding on the security of your mobile account. The most common form of secondary authentication a one-time code sent to your mobile device via SMS/text message is also the least secure. Some of the more popular online services offer multiple options for multiple options.”]
Source: https://krebsonsecurity.com/2017/08/is-your-mobile-carrier-your-weakest-link/