The problem with multi-factor authentication is its overuse. I would also hate physical keys if every single door I came across required me to unlock it.
When you already have so many logins that you start using a password manager, your passwords are already high entropy enough that they don't get brute forced and a leak doesn't compromise your other accounts. TOTP adds challenge response to this, so it is actually a bit better than a password since an interception cannot be reused, but they are both still shared secret and in both cases need to be stored in some other device (password manager vs TOTP code manager). For most logins that don't require real security I just use my password manager for both so it is just a disjoint shared secret approach. Nevertheless, TOTP "increases security" for websites (but not my security specifically) because the shared secret is generated by the website owner so is definitely unique and not reused unlike many other user's passwords.
I expect the majority of people are storing their TOTP secrets on the device they are logging in from (their mobile device) and so have single points of vulnerability. So multifactor auth is typically just a disjoint shared secret with a partial challenge. The extra security is just created because the website forces true random shared secret. We could have all this with a single factor.
> When I tell people I work on authentication software, I nearly always hear some version of the same story: I hate multifactor authentication. No, really. People hate this stuff.
I hate all of the half-cooked non-TOTP MFA methods that I'm forced to use. Just let me use my freaking authenticator app. If you believe that your users prefer (or maybe it's just you?) more databroker-friendly methods, then fine, but please at least provide TOTP as an option.
I wish that banks would offer TOTP. SMS is famously insecure and poorly suited for something that’s a load-bearing pillar in most of our lives, and TOTP is probably the most reasonable replacement. Unfortunately only a tiny handful of US banks offer non-SMS 2FA of any kind, and to my knowledge the one that does (Scwhab I think?) requires the use of a hardware gadget even though it’s standard TOTP (which people have written python scripts to extract the necessary bits of info from).
World of Warcraft was supporting tens of thousands poor teenagers in developing countries, who would farm high value items in the game and then sell the account /items to rich people who didn't want to put in the hard work.
There was (maybe still is) lots of money to be made by hacking accounts and selling them.
At least in Germany all the SMS 2FA has been shut off, but replaced with tons of custom 2FA apps. The security argument is certainly that they can check for 'insecure' devices. But I wonder what the empirical evidence here is and how often (compared to phishing/social engineering) a TOTP token was actually stolen. Worst thing is IMHO Microsoft now which seem to have also shut off the TOTP option and use some other propriatary 2FA scheme now. IMHO banks should simply use FIDO2 HW tokens, but with all that passkey bullshit it becomes unlikely...
Yes, for the love of god and all that is holy, just let me use TOTP for MFA. I absolutely HATE that some banks use SMS as a method of MFA. Sometimes it's a mix of 8 character numeric password with SMS as MFA.
The only 2FA I'm using is the one of my bank, because I must (there are regulations.)
I stopped logging in into GitHub since they enforced 2FA on my account. Luckily no current customer of mine is using GitHub. They are on Bitbucket and it does not require 2FA yet.
A number of services that I use ask me to enable 2FA. I skip the offer everytime.
The worst 2FAs are SMS based: not because of the (in)security of SMSes but because I don't receive SMSes when I'm outside of my country.
I never received a SMS from Italy when I was on vacation in Australia in 2019. Apparently my phone contract would allow them but either the phone company did not honor its terms or banks didn't send SMSes to roaming customers. I ended up using Italian payment services that either had their own app or other methods to perform 2FA. I also had an Australian SIM but there were no chances to associate it to my accounts. I guess that it's fair, because a foreign number all of a sudden is a red flag for a stolen account.
And nobody sent SMS to me, everybody used WhatsApp or similar services.
Quite funny. Amusingly, the self-portrait method is effectively the signatures we considered acceptable for financial and legal transactions for many decades - make up a scribble and compare it to a scribble you do previously - if it's close enough and you _seem_ to be the guy, we're good.
> make up a scribble and compare it to a scribble you do previously
I'll take "Lies that your parents told you about how the world works" for 500, Alex.
Serious question though, I thought the whole signature thing was more of a legally binding thing for the signer asserting themselves as X, sort of like checking the "I'm over 18" box. Sort of a "Well we asked you the question, it's not our fault if you lied" type thing.
"lies that your American parents told you about how the world works"
i went to Germany as an exchange student, scribbled out my random scribble for my travellers check, and they denied me because my signature wasn't close enough to their record. heard a similar story from a friend who visited Japan
And in India when you need lots of cash from your own account, you need to sign a withdrawal slip, and signatures on that need to match exactly the original signatures on their file.
When I got my first credit card, circa mid-90s, no one told me I had to sign the bank. Took my brand new card with my brand new girlfriend to a shop and bought something.
Handed the clerk my card during payment, she looked at it and said it is not signed so she is not allowed to accept it. I took it back, she gave me a pen, I signed it and gave it back to her.
She ran the transaction, got an approved slip, gave me the slip to sign, I signed it and gave it back.
She compared the signature on the slip to the signature on the back of the car, and Lo And Behold, They Matched!
I personally don't mind this because I've been burned too many times by services that mangle a new password in some invisible way, for example silent truncation, so I like the opportunity to log in just to make sure that the update has worked, the value in my password manager is correct, etc.
Signatures are the tip of the iceberg. Plenty of other forms of bs forensics live on in the legal system in some shape or form. e.g., fingerprint analysis, polygraphs, field sobriety tests, devices that literally do nothing, trainings on reading facial expressions, and so on. If you can take a two week course on it, then chances are there is some cop somewhere using it to detain people.
I always do a random scribble. If I want to later deny signing something good luck proving its me, won't match any of my other signatures. At least that's the theory, this is mostly a joke to me and I don't care if it works.
A fingerprint locked NFC Yubikey seems to be the preferred with all ages at work. Everyone likes it as long as it is once per login to the computer (which basically means we have to use Edge for everything which is fine).
Everyone universally hates passkeys because they never work right.
Except for those whose fingerprints don't work (climbing wears away fingerprints). I have even heard of people struggling to renew their passports because of difficulties getting their fingerprints read.
Many manual jobs wear away fingerprints. I renewed my ID card after renovating my home and the fingerprint reader could not read anything meaningful. They told me that sometimes the state accepts those messy fingerprints anyway and yes, the request got approved. There is some jumbled fingerprint on my record now.
Poker hands would pretty cool for encoding things that you have to recognize quickly; e.g., key fingerprints. If there are 2.5M unique hands then encoding 256 bits of information requires 12(ish) poker hands.
I know that the article is a joke, but the last one is (or was?) actually used by Facebook as a forced mfa when it suspected a correct login to be "suspicious".
Of course, it's also a way to force users to tag their contact's photos and train Facebook's face detector by holding your account hostage until you comply, similar to those CAPTCHA street view challenges.
Besides, it only works if the attacker is a stranger, if it's an acquaintance (or a very dedicated stalker) then it doesn't work so well anymore.
One aspect I find puzzling is why most two-factor authentication (2FA) applications restrict authentication to only a single valid code at any given time. This constraint inevitably creates a window during which it is inconvenient or impractical to copy the code to another device. Allowing the previous code to remain briefly valid would eliminate this unnecessary delay, enhancing usability without significantly compromising security.
This is all in the standard, most places have implemented one of the options. I've implemented all of the options at least once. It's configurable based on how lax/secure you want to be.
Most places I've dealt with allow the previous and next code to also be used, so instead of a 30s window you actually have a 1.5m window.
Have you actually tried writing a code close to the expiry window? I've definitely submitted codes a few seconds after the expiry and had them still be accepted
Ente Auth displays the current code and the next code so you can choose whichever best meets the time remaining until the changeover. It’s a nice usability feature.
Since totp codes are time based and there is no guarantee that time of the generating device, and the verifying device are exactly identical they usually allow some room for error. You'll probably be fine entering the code before or after for example.
Pedantry warning: I'm not convinced that some of these methods qualify as a second factor of authentication, based on the "something you know, something you have, something you are" model. They're both "something you know", right?
Imagine two different password strength standards:
1. Just a 4 digit numeric PIN like `1981`
2. A 20 character upper/lower/numeric/special-character password like `qmd1tkf7mwa.PQB0qrz$`
--
The PIN has lower entropy and is therefore a lot easier to brute force.
I haven't calculated this stuff myself -- I just used Wolfram Alpha -- but it looks like the PIN would take <1 second to brute force, while the 20 character password would take 7.6 * 10^25 years. [1] [2]
The problem with multi-factor authentication is its overuse. I would also hate physical keys if every single door I came across required me to unlock it.
When you already have so many logins that you start using a password manager, your passwords are already high entropy enough that they don't get brute forced and a leak doesn't compromise your other accounts. TOTP adds challenge response to this, so it is actually a bit better than a password since an interception cannot be reused, but they are both still shared secret and in both cases need to be stored in some other device (password manager vs TOTP code manager). For most logins that don't require real security I just use my password manager for both so it is just a disjoint shared secret approach. Nevertheless, TOTP "increases security" for websites (but not my security specifically) because the shared secret is generated by the website owner so is definitely unique and not reused unlike many other user's passwords.
I expect the majority of people are storing their TOTP secrets on the device they are logging in from (their mobile device) and so have single points of vulnerability. So multifactor auth is typically just a disjoint shared secret with a partial challenge. The extra security is just created because the website forces true random shared secret. We could have all this with a single factor.
> When I tell people I work on authentication software, I nearly always hear some version of the same story: I hate multifactor authentication. No, really. People hate this stuff.
I hate all of the half-cooked non-TOTP MFA methods that I'm forced to use. Just let me use my freaking authenticator app. If you believe that your users prefer (or maybe it's just you?) more databroker-friendly methods, then fine, but please at least provide TOTP as an option.
I wish that banks would offer TOTP. SMS is famously insecure and poorly suited for something that’s a load-bearing pillar in most of our lives, and TOTP is probably the most reasonable replacement. Unfortunately only a tiny handful of US banks offer non-SMS 2FA of any kind, and to my knowledge the one that does (Scwhab I think?) requires the use of a hardware gadget even though it’s standard TOTP (which people have written python scripts to extract the necessary bits of info from).
To this day I'm just amazed that World of Warcraft tried to mandate security tokens in a time when E*Trade barely supported them.
Why is a video game embarrassing fintech?
World of Warcraft was supporting tens of thousands poor teenagers in developing countries, who would farm high value items in the game and then sell the account /items to rich people who didn't want to put in the hard work.
There was (maybe still is) lots of money to be made by hacking accounts and selling them.
WoW was fintech!
>WoW was fintech!
WOW was teaching kids how free market capitalism works early on.
Fidelity offers TOTP standard support, works with the native Apple Password app/keychain.
At least in Germany all the SMS 2FA has been shut off, but replaced with tons of custom 2FA apps. The security argument is certainly that they can check for 'insecure' devices. But I wonder what the empirical evidence here is and how often (compared to phishing/social engineering) a TOTP token was actually stolen. Worst thing is IMHO Microsoft now which seem to have also shut off the TOTP option and use some other propriatary 2FA scheme now. IMHO banks should simply use FIDO2 HW tokens, but with all that passkey bullshit it becomes unlikely...
No it hasn't. How can you make a statement so confident, when obviously you couldn't objectively know?
Yes, for the love of god and all that is holy, just let me use TOTP for MFA. I absolutely HATE that some banks use SMS as a method of MFA. Sometimes it's a mix of 8 character numeric password with SMS as MFA.
A passkey is far better than TOTP for security to the point that TOTP should probably be deprecated already.
Passkeys don't replace all use-cases for TOTP
TOTP still seems good enough for most things
It's like picking WEP for your wifi
https://www.cisa.gov/sites/default/files/publications/fact-s...
At best WPA2. WEP is broken in ways that don't need human fault.
The only downside of TOTP to FIDO and friends (from a security perspective) is phishing resistance
That's a pretty major downside to OTP's and certainly not one that can be offhandedly dismissed.
The only 2FA I'm using is the one of my bank, because I must (there are regulations.)
I stopped logging in into GitHub since they enforced 2FA on my account. Luckily no current customer of mine is using GitHub. They are on Bitbucket and it does not require 2FA yet.
A number of services that I use ask me to enable 2FA. I skip the offer everytime.
The worst 2FAs are SMS based: not because of the (in)security of SMSes but because I don't receive SMSes when I'm outside of my country.
>because I don't receive SMSes when I'm outside of my country
What?! I've never had that issue.
I never received a SMS from Italy when I was on vacation in Australia in 2019. Apparently my phone contract would allow them but either the phone company did not honor its terms or banks didn't send SMSes to roaming customers. I ended up using Italian payment services that either had their own app or other methods to perform 2FA. I also had an Australian SIM but there were no chances to associate it to my accounts. I guess that it's fair, because a foreign number all of a sudden is a red flag for a stolen account.
And nobody sent SMS to me, everybody used WhatsApp or similar services.
[dead]
Quite funny. Amusingly, the self-portrait method is effectively the signatures we considered acceptable for financial and legal transactions for many decades - make up a scribble and compare it to a scribble you do previously - if it's close enough and you _seem_ to be the guy, we're good.
> make up a scribble and compare it to a scribble you do previously
I'll take "Lies that your parents told you about how the world works" for 500, Alex.
Serious question though, I thought the whole signature thing was more of a legally binding thing for the signer asserting themselves as X, sort of like checking the "I'm over 18" box. Sort of a "Well we asked you the question, it's not our fault if you lied" type thing.
"lies that your American parents told you about how the world works"
i went to Germany as an exchange student, scribbled out my random scribble for my travellers check, and they denied me because my signature wasn't close enough to their record. heard a similar story from a friend who visited Japan
And in India when you need lots of cash from your own account, you need to sign a withdrawal slip, and signatures on that need to match exactly the original signatures on their file.
I remember opening a bank account and having to sign a specific card that the bank would keep solely to verify my signature on checks.
When I got my first credit card, circa mid-90s, no one told me I had to sign the bank. Took my brand new card with my brand new girlfriend to a shop and bought something.
Handed the clerk my card during payment, she looked at it and said it is not signed so she is not allowed to accept it. I took it back, she gave me a pen, I signed it and gave it back to her.
She ran the transaction, got an approved slip, gave me the slip to sign, I signed it and gave it back.
She compared the signature on the slip to the signature on the back of the car, and Lo And Behold, They Matched!
Like logging in after a password reset.
I personally don't mind this because I've been burned too many times by services that mangle a new password in some invisible way, for example silent truncation, so I like the opportunity to log in just to make sure that the update has worked, the value in my password manager is correct, etc.
Signatures are the tip of the iceberg. Plenty of other forms of bs forensics live on in the legal system in some shape or form. e.g., fingerprint analysis, polygraphs, field sobriety tests, devices that literally do nothing, trainings on reading facial expressions, and so on. If you can take a two week course on it, then chances are there is some cop somewhere using it to detain people.
I always do a random scribble. If I want to later deny signing something good luck proving its me, won't match any of my other signatures. At least that's the theory, this is mostly a joke to me and I don't care if it works.
A fingerprint locked NFC Yubikey seems to be the preferred with all ages at work. Everyone likes it as long as it is once per login to the computer (which basically means we have to use Edge for everything which is fine).
Everyone universally hates passkeys because they never work right.
Except for those whose fingerprints don't work (climbing wears away fingerprints). I have even heard of people struggling to renew their passports because of difficulties getting their fingerprints read.
Many manual jobs wear away fingerprints. I renewed my ID card after renovating my home and the fingerprint reader could not read anything meaningful. They told me that sometimes the state accepts those messy fingerprints anyway and yes, the request got approved. There is some jumbled fingerprint on my record now.
It sounds like you're talking about passkeys though? (FIDO2) Or are you using PIV on all of those keys?
whisper that Yubikey is holding the passkey data ;)
I still don't know what a passkey is, but since Microsoft pushes for it, I assume I'll probably hate it
Poker hands would pretty cool for encoding things that you have to recognize quickly; e.g., key fingerprints. If there are 2.5M unique hands then encoding 256 bits of information requires 12(ish) poker hands.
I know that the article is a joke, but the last one is (or was?) actually used by Facebook as a forced mfa when it suspected a correct login to be "suspicious".
Of course, it's also a way to force users to tag their contact's photos and train Facebook's face detector by holding your account hostage until you comply, similar to those CAPTCHA street view challenges.
Besides, it only works if the attacker is a stranger, if it's an acquaintance (or a very dedicated stalker) then it doesn't work so well anymore.
One aspect I find puzzling is why most two-factor authentication (2FA) applications restrict authentication to only a single valid code at any given time. This constraint inevitably creates a window during which it is inconvenient or impractical to copy the code to another device. Allowing the previous code to remain briefly valid would eliminate this unnecessary delay, enhancing usability without significantly compromising security.
See RFC-6238: https://www.rfc-editor.org/rfc/rfc6238
This is all in the standard, most places have implemented one of the options. I've implemented all of the options at least once. It's configurable based on how lax/secure you want to be.
Most places I've dealt with allow the previous and next code to also be used, so instead of a 30s window you actually have a 1.5m window.
Have you actually tried writing a code close to the expiry window? I've definitely submitted codes a few seconds after the expiry and had them still be accepted
I believe every single 2fa system I've used accepts either the current code or the one directly prior.
FWIW 2FAS starts to show you the next code near the end of the window, this is very handy https://2fas.com/
Ente Auth displays the current code and the next code so you can choose whichever best meets the time remaining until the changeover. It’s a nice usability feature.
Since totp codes are time based and there is no guarantee that time of the generating device, and the verifying device are exactly identical they usually allow some room for error. You'll probably be fine entering the code before or after for example.
Pedantry warning: I'm not convinced that some of these methods qualify as a second factor of authentication, based on the "something you know, something you have, something you are" model. They're both "something you know", right?
These are such terrible ideas that I expect someone already has one of them on github.
Why do we like entropy in auth factors?
Imagine two different password strength standards:
1. Just a 4 digit numeric PIN like `1981`
2. A 20 character upper/lower/numeric/special-character password like `qmd1tkf7mwa.PQB0qrz$`
--
The PIN has lower entropy and is therefore a lot easier to brute force.
I haven't calculated this stuff myself -- I just used Wolfram Alpha -- but it looks like the PIN would take <1 second to brute force, while the 20 character password would take 7.6 * 10^25 years. [1] [2]
--
[1] https://www.wolframalpha.com/input?i=password+strength+qmd1t...
[2] https://www.wolframalpha.com/input?i=password+strength+1981