Comment on Millions of people imperiled through sign-in links sent by SMS
irotsoma@piefed.blahaj.zone 2 days agoHow so?
It’s a second factor. It’s “something you know”, “something you have”, and/or “something you are”. The username and password is the “something you know” and the sms message is “something you have” (I.e. the phone). There’s no need for the second factor to be secret as long as it is single use and time sensitive and is only used as a second factor, not the only factor.
This article was about single factor messages that are the entirety of the login flow, so not about 2FA, but I’m still interested in the concerns for second factor. It is still adding security over a password alone which is the only goal in the 2FA subject.
artyom@piefed.social 2 days ago
All of the same reasons for single factor also apply to MFA.
It’s also dependent on other services, is a privacy violation, and a giant fucking pain in the ass if you ever want to change your phone number, or like me, you have service issues.
There are many other alternate, more secure, more convenient, more resilient options.
irotsoma@piefed.blahaj.zone 2 days ago
Problem is finding something that is universal that is a “something you have” is difficult to find that almost everyone has. Almost everyone has a cell phone these days, so it’s a good option to use as that kind of factor. Email is a second “something you know” factor (I.e. via the password to your email account) and could be the same something if you use the same password. And getting someone to carry yet another device even if it’s simple like a Yubikey or something like that can be difficult. And unless biometric devices become universal on computers as well as phones, the “something you are” factor is hard to accomplish universally as well.
So, what options do you think are better that can be a “something you have” for use as a second factor to a password or other type of “something you know” factor?
artyom@piefed.social 2 days ago
TOTP or passkey are my preferred MFA options
irotsoma@piefed.blahaj.zone 2 days ago
SMS 2FA is TOTP, just the code is sent via SMS and the key is never shared with the user. But the issue with those apps seems to be even more problematic than SMS from the issues mentioned, e.g. changing phone numbers is not as common as changing phones or other catastrophic events that might cause the keys to get lost. And if you store passkeys or TOTP generating keys in the cloud, then the factor is no longer “something you have” because anyone can get the keys if they get the password to the thing storing the keys. SMS based TOTP leaves the keys only with the site you’re logging into and only the time sensitive TOTP codes are ever sent out. And although the lifetime period for sms TOTP has to be longer, they are additionally expired on single use (assuming it’s implemented properly).