SMS-Based 2FA Still Needed Despite NIST Guidelines: Security Expert

While SMS-based two-factor authentication isn't the most secure version of 2FA, it's still far better than not using 2FA, security expert Shaun Murphy tells eWEEK.

two-factor authentication

The U.S. National Institute of Standards and Technology (NIST), in its updated Digital Authentication Guidelines, claims SMS-based two-factor authentication isn't secure and should be banned. And at least one security expert is taking exception to that stance.

"For everyday users, two-factor authentication is a phenomenal thing," said Shaun Murphy, a security expert, inventor and most recently the co-founder and CEO of Sndr, an app that combines communications methods onto a single platform.

eWEEK spoke with Murphy in light of NIST's updated guidelines.

"To hear that two-factor authentication [also known as 2FA] over SMS isn't secure is a pretty sad thing to hear," said Murphy, anecdotally describing that anyone could go on the dark web right now, buy 10 million user names and passwords, and get right into an account—unless that account is protected by a second factor, in which case the password is useless to the hacker.

"So what do we do? Do we give up and say SMS isn't safe? I think that's not a smart thing to do right now," said Murphy.

While SMS can definitely be compromised, whether by social engineering (someone pretending to be someone else and getting their carrier to send a new SIM, for example) or by sniffing traffic over a WiFi connection, he explained, using two-factor authentication over SMS is still preferable to a single password.

"There are a lot of facets to why the NIST is recommending why not to use this, or that their guidance is to move away from it as soon as possible," said Murphy. "And I think their position is that there are stronger alternatives to what the SMS two-factor authentication gives you. And that's true."

Murphy said he uses a hardware device for two-factor authentication, as well as an app on his phone that generates a time-based one-time password (TOTP), for things like logging into his Amazon Web Services account.

"That's probably where we're going. Instead of companies sending you an SMS, I think that's what they'll start to require," said Murphy. "The biggest problem with that is it's not built into the phone. … So you have to go through the extra step of installing the application, configuring it, scanning in a QR code. Most people won't do that—but they will do the SMS thing. … That's the problem we're facing with this recommendation."

If you're not a high-profile person, these kinds of attacks likely aren't going to happen to you, suggests Murphy. But if you're a high-profile person, like a CEO, a secretary of state, a vice president, etc., "There are just too many ways, too many attack vectors, to get that information. I think that's why they're saying we're just going to deprecate it and get rid of it and have other techniques for second-factor authentication."

That said, he added, "There's an interpretation that SMS two-factor authentication isn't good, so we're not going to use two-factor authentication. And I think that's the wrong interpretation."

Essentially, if unsurprisingly, how secure you are comes down to how willing you are to put in a bit more effort.

"If you're willing to go the extra step and use a stronger two-factor authentication, I think it's absolutely worthwhile and everyone should do it—not just high-profile targets," said Murphy.

"But if you're on the fence about using two-factor authentication and SMS gets you in the door, I'm all for it."