Two-factor authentication

Many online services offer two-factor authentication (2fa) to protect users’ accounts. When you enable 2fa on an account, it means that you still log in with a username and password, but then you have to enter a one-time code before you can access your account. How you get the code (typically a six-digit number) depends on the implementation: twitter sends you the code in an SMS text message, while others (like google and facebook) have you look up the code in a mobile app. Either way, you generally get the code with your phone. The point of this is to make it harder for someone to break into your online account, because they’d have to know your password and have access to your phone.

So logging in with 2fa means taking an extra step which at times can feel like a nuisance. The way I look at it is that it’s a minor inconvenience for me, but it’s a significant inconvenience to someone who wants to steal my account.

2fa isn’t a new innovation. I knew someone in the late 1990s who worked for a government-funded research facility, and he carried around a little device in his pocket. When he needed to log in to one of the facility’s computers, he’d have to look at the code that appeared on the device’s screen and enter that code in order to complete his login process. It worked very much like modern 2fa implementations.

More and more online services are offering 2fa, and I encourage you to start using it wherever you can. The Two Factor Auth (2FA) web site provides of list of who does and who doesn’t offer 2fa login features. This can be a good place to see which of your accounts have 2fa available, and the 2fa site typically has a link to the documentation on how to set up 2fa for each service.

2fa makes it a lot harder for someone to take over an account, but it’s not perfect (and this is the part that might be useful to a writer who needs her main character to defeat a 2fa-protected account). Someone gained control of the twitter account of political activist DeRay Mckesson, an account that had 2fa enabled. The criminal contacted Verizon (Mckesson’s mobile provider) and convinced the billing department that Mckesson’s cell phone number had changed. So SMS messages that should have gone to Mckesson instead went to the criminal’s phone. The criminal then used twitter’s “forgot my password” feature and received an SMS message with the code the criminal needed to complete the account theft.

This is a good reminder of how effective social engineering can be. Some people will do anything to end a phone conversation with an angry-sounding customer. Sometimes the best hacks exploit people, not computers.

By the way, that Naked Security post (near the end) has some tips on how to enable security features on the accounts of several mobile providers, including Verizon. That might or might not have made a difference in DeRay Mckesson’s incident, but it might have made it easier for him to regain control of his Verizon account.


Author: carl

A web programmer and Linux system administrator who would like to be a writer.