18 ms·

Playing with more user-friendly methods for multi-factor authentication

79 points by noleary 1y ago

averageRoyalty 1y ago
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.
- sunrunner 1y ago
  > 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.
  - j-bos 1y ago
    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.
    - lelanthran 1y ago
      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!
      - HPsquared 1y ago
        Like logging in after a password reset.
        sunrunner 1y ago
        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.
  - progbits 1y ago
    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.
  - boogieknite 1y ago
    "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
    - davchana 1y ago
      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.
  - evantbyrne 1y ago
    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.
    - arccy 1y ago
      fingerprints seem pretty solid?
      - tialaramex 1y ago
        On a good day, with an excellent print and the best people doing the matching you can be pretty sure if this print is from this person, but crime scenes are not that perfect scenario and the actual crime scene investigator might be less than great at the matching or influenced to some extent by what their boss wants. There's a big difference between "This thumbprint in blood was on the recovered murder weapon and it's a perfect match" and "This smudge of half a finger on a paper bag found near the scene was arguably a match" but the jury isn't necessarily told about this and where on that scale the evidence they've been told about would lie.
      - evantbyrne 1y ago
        Standards vary wildly on what constitutes a fingerprint match. There can be well over 100 ridge characteristics in a fingerprint, but some US jurisdictions only require as few as 12 of them to match, and it all comes down to an investigator's subjective determination anyways. It is not scientific.
FuriouslyAdrift 1y ago
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.
- Ferret7446 1y ago
  It sounds like you're talking about passkeys though? (FIDO2) Or are you using PIV on all of those keys?
  - FuriouslyAdrift 1y ago
    Fido2
- esseph 1y ago
  whisper that Yubikey is holding the passkey data ;)
  - 01HNNWZ0MV43FF 1y ago
    I still don't know what a passkey is, but since Microsoft pushes for it, I assume I'll probably hate it
    - esseph 1y ago
      Everybody is pushing for it, Microsoft is just being dragged along.
  - FuriouslyAdrift 1y ago
    I’m referring to the browser based ‘passkey’ everyone is pushing right now
- BlackFly 1y ago
  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.
1970-01-01 1y ago
These are such terrible ideas that I expect someone already has one of them on github.
seplox 1y ago
> 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.
- cosmic_cheese 1y ago
  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).
  - toomuchtodo 1y ago
    Fidelity offers TOTP standard support, works with the native Apple Password app/keychain.
    - cpburns2009 1y ago
      Only recently. They used to require Symantec's authenticator.
  - hinkley 1y ago
    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?
    - abdullahkhalids 1y ago
      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!
thcipriani 1y ago
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.
smokel 1y ago
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.
- brewdad 1y ago
  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.
- fredley 1y ago
  FWIW 2FAS starts to show you the next code near the end of the window, this is very handy https://2fas.com/ https://2fas.com/
- conradludgate 1y ago
  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
  - michaelt 1y ago
    Some users clocks are a minute or two out, so sensible TOTP implementations will actually accept about 5 codes to account for clock error.
- _Algernon_ 1y ago
  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.
- zie 1y ago
  See RFC-6238: https://www.rfc-editor.org/rfc/rfc6238 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.
anteloper 1y ago
Why do we like entropy in auth factors?
- noleary 1y ago
  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+qmd1tkf7mwa.PQB0qrz%24 https://www.wolframalpha.com/input?i=password+strength+qmd1t... [2] https://www.wolframalpha.com/input?i=password+strength+1981 https://www.wolframalpha.com/input?i=password+strength+1981
Liftyee 1y ago
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?
- 542354234235 1y ago
  That is actually multifactor. Second factor is just any additional factor.
marc_abonce 1y ago
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.
BlackFly 1y ago
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.
- _Algernon_ 1y ago
  Why couldn't we combine the two? Make TOTP based on a higher-entropy secret with longer generated codes the only factor. This would prevent replay attacks of entered passwords, thus protecting against phishing, and ensure users have safe secrets (since the site generates the secret).
  - BlackFly 1y ago
    That's my preference. For some things I would be willing to have the increased security of a genuinely separate device.
pmontra 1y ago
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.
- FirmwareBurner 1y ago
  >because I don't receive SMSes when I'm outside of my country What?! I've never had that issue.
  - pmontra 1y ago
    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.
    - pinoy420 1y ago
      [dead]
PeterStuer 1y ago
Please, non of these. Just a QR code with an authenticator app of my choice.
- harwell 1y ago
  It’s a joke
jerjerjer 1y ago
> It's incredibly easy to remember your hand. Just ask any of your friends that play poker -- they can surely remember a bad beat. And it's pretty much impossible for an attacker to guess. There's an implication here that users would pick a random hand. I'm sure a set containing all flushes, straights, full houses and four of a kind would account for most of the used passwords.
zzo38computer 1y ago
I would want X.509 client authentication. You can use a passworded private key if wanted (and the server will not need to know your password), and there are other benefits with security and other stuff, compared with the more common 2FA and cookies and that stuff. It also ensures better that the client and server are communicating with each other that they want to rather than someone else that they don't want, then merely using X.509 server authentication only.

79 points by noleary 1y ago

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.

sunrunner 1y ago
> 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.
- j-bos 1y ago
  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.
  - lelanthran 1y ago
    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!
    - HPsquared 1y ago
      Like logging in after a password reset.
      - sunrunner 1y ago
        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.
- progbits 1y ago
  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.
- boogieknite 1y ago
  "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
  - davchana 1y ago
    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.
- evantbyrne 1y ago
  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.
  - arccy 1y ago
    fingerprints seem pretty solid?
    - tialaramex 1y ago
      On a good day, with an excellent print and the best people doing the matching you can be pretty sure if this print is from this person, but crime scenes are not that perfect scenario and the actual crime scene investigator might be less than great at the matching or influenced to some extent by what their boss wants. There's a big difference between "This thumbprint in blood was on the recovered murder weapon and it's a perfect match" and "This smudge of half a finger on a paper bag found near the scene was arguably a match" but the jury isn't necessarily told about this and where on that scale the evidence they've been told about would lie.
    - evantbyrne 1y ago
      Standards vary wildly on what constitutes a fingerprint match. There can be well over 100 ridge characteristics in a fingerprint, but some US jurisdictions only require as few as 12 of them to match, and it all comes down to an investigator's subjective determination anyways. It is not scientific.

FuriouslyAdrift 1y ago

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.

Ferret7446 1y ago
It sounds like you're talking about passkeys though? (FIDO2) Or are you using PIV on all of those keys?
- FuriouslyAdrift 1y ago
  Fido2
esseph 1y ago
whisper that Yubikey is holding the passkey data ;)
- 01HNNWZ0MV43FF 1y ago
  I still don't know what a passkey is, but since Microsoft pushes for it, I assume I'll probably hate it
  - esseph 1y ago
    Everybody is pushing for it, Microsoft is just being dragged along.
- FuriouslyAdrift 1y ago
  I’m referring to the browser based ‘passkey’ everyone is pushing right now
BlackFly 1y ago
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.

1970-01-01 1y ago

These are such terrible ideas that I expect someone already has one of them on github.

seplox 1y ago

> 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.

cosmic_cheese 1y ago
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).
- toomuchtodo 1y ago
  Fidelity offers TOTP standard support, works with the native Apple Password app/keychain.
  - cpburns2009 1y ago
    Only recently. They used to require Symantec's authenticator.
- hinkley 1y ago
  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?
  - abdullahkhalids 1y ago
    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!

thcipriani 1y ago

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.

smokel 1y ago

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.

brewdad 1y ago
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.
fredley 1y ago
FWIW 2FAS starts to show you the next code near the end of the window, this is very handy https://2fas.com/ https://2fas.com/
conradludgate 1y ago
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
- michaelt 1y ago
  Some users clocks are a minute or two out, so sensible TOTP implementations will actually accept about 5 codes to account for clock error.
_Algernon_ 1y ago
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.
zie 1y ago
See RFC-6238: https://www.rfc-editor.org/rfc/rfc6238 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.

anteloper 1y ago

Why do we like entropy in auth factors?

noleary 1y ago
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+qmd1tkf7mwa.PQB0qrz%24 https://www.wolframalpha.com/input?i=password+strength+qmd1t... [2] https://www.wolframalpha.com/input?i=password+strength+1981 https://www.wolframalpha.com/input?i=password+strength+1981

Liftyee 1y ago

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?

542354234235 1y ago
That is actually multifactor. Second factor is just any additional factor.

marc_abonce 1y ago

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.

BlackFly 1y ago

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.

_Algernon_ 1y ago
Why couldn't we combine the two? Make TOTP based on a higher-entropy secret with longer generated codes the only factor. This would prevent replay attacks of entered passwords, thus protecting against phishing, and ensure users have safe secrets (since the site generates the secret).
- BlackFly 1y ago
  That's my preference. For some things I would be willing to have the increased security of a genuinely separate device.

pmontra 1y ago

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.

FirmwareBurner 1y ago
>because I don't receive SMSes when I'm outside of my country What?! I've never had that issue.
- pmontra 1y ago
  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.
  - pinoy420 1y ago
    [dead]

PeterStuer 1y ago

Please, non of these. Just a QR code with an authenticator app of my choice.

harwell 1y ago
It’s a joke

jerjerjer 1y ago

> It's incredibly easy to remember your hand. Just ask any of your friends that play poker -- they can surely remember a bad beat. And it's pretty much impossible for an attacker to guess. There's an implication here that users would pick a random hand. I'm sure a set containing all flushes, straights, full houses and four of a kind would account for most of the used passwords.

zzo38computer 1y ago

I would want X.509 client authentication. You can use a passworded private key if wanted (and the server will not need to know your password), and there are other benefits with security and other stuff, compared with the more common 2FA and cookies and that stuff. It also ensures better that the client and server are communicating with each other that they want to rather than someone else that they don't want, then merely using X.509 server authentication only.