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Random passwords in a password manager are also phishing-resistant. My password manager remembers the URL that I used the password in and will refuse to fill it

Random passwords in a password manager are also phishing-resistant. My password manager remembers the URL that I used the password in and will refuse to fill it in on other pages unless I deliberately work around that protection. They may be less phishing-resistant than passkeys (in which case add it to the list of small disagreements I have with the original poster), but it's not a wide open field for phishing attacks. And this is an important distinction to make—if passkeys have a terrible UX (which right now they absolutely do) and are only marginally better at phishing protection than a password manager, they could actually be a less secure solution overall by encouraging lazy workarounds.

afiori 2y ago
One big selling point of passkeys is that almost every workaround is impossible, whether that is good security or bad UX or both seems to be under discussion
- lolinder 2y ago
  If that's one of the big selling points then that's a problem, because workarounds are totally possible and actively implemented in the real world. As an obvious example: syncing passkeys is a workaround for their terrible UX that takes them further from the original design in ways that compromise some of the original security guarantees.
  - wglb 2y ago
    Can you illustrate how workarounds to passkeys are being actively implemented?
    - fragmede 2y ago
      Password manager support. If my password manager running on my desktop can provision and access the passkey for use on another device like my phone, then so can malicious code running on my desktop, and exfiltrate it to hackers. The original design, where the private key only exists on a TPM and the private key never leaves the TPM doesn't have that flaw.
      - lxgr 2y ago
        Passkeys were always designed as being synchronizable and not necessarily be secure hardware backed. I think there’s a place for both of them in WebAuthN based on the security/availability/convenience tradeoff which will be different for every application. If you care about your users only using the trusted hardware, non-synchronizing kind, you have to use attestation anyway (or malware running on their device could create credentials that only appear to be backed by secure hardware). Unfortunately both Apple and Google seem to have unshipped their attestation support without replacement (they used to support hardware backed credentials in their devices too for a while) in the interest of not confusing users about what is and isn’t synchronized – now everything is.
        wkat4242 2y ago
        Attestation would be terrible to have in passkeys because it will allow sites to block certain implementations. PayPal does this already by only allowing safari or chrome. With bitwarden on Firefox I'm locked out.
        lxgr 2y ago
        Yeah, as a user, I'm mostly happy about the lack of attestation. In an ideal world, only relying parties that really need it would request it, but views on who really does might obviously differ a lot between users and service providers. > PayPal does this already by only allowing safari or chrome. With bitwarden on Firefox I'm locked out. It works for me! However I do vaguely remember having to set them up on Chrome initially, but after that, they now work well even in Firefox. (Only on my computer; on my phone, I get an absurd non sequitur of "security keys only work on desktops").
        wkat4242 2y ago
        > It works for me! However I do vaguely remember having to set them up on Chrome initially, but after that, they now work well even in Firefox. (Only on my computer; on my phone, I get an absurd non sequitur of "security keys only work on desktops"). Oh ok, I haven't tried that. I don't even have Chrome installed anymore. And yeah I get that message too on my phone, even with standard FIDO2 MFA (not full passwordless Webauthn). Stupid because it does work just fine with other sites.
tptacek 2y ago
Passkeys are cryptographically phishing-resistant, and password managers just disable a convenience feature when a heuristic check fails. It's not the same thing. I don't care if you feel like the latter protection is sufficient for you or should be for others; they simply aren't the same, and that was what the comment upthread suggested.
- lolinder 2y ago
  Whether or not they're the same as a bit of a red herring, the question is whether the marginal added benefit of cryptographic phishing resistance is worth the trade-off in UX which introduces new kinds of vulnerabilities due to undesirable user behavior and/or implementation workarounds. And to answer that question you can't just dismiss the security offered by password managers—it's a very real protection that needs to be factored in to your assessment of the strengths and weaknesses of each system.
  - tptacek 2y ago
    Take it up with the person who said the two countermeasures were literally equivalent. You're not going to get anywhere with me on this.
    - lolinder 2y ago
      Which user/comment are you referring to? The top-level comment? I'm the person you replied to initially, and that's not what I said, so I'm assuming you're referring to something else.
      - tptacek 2y ago
        passkeys stored in a password manager aren't any more secure in practical terms than random passwords stored in a password manager It is my contention that this statement is: 1. Categorical, 2. False, and 3. Categorically false
        2y ago
lxgr 2y ago
Not at all. One phishing vector is: (On a phone call) "Hi, this is $your_bank, please go to your password manager, open the entry for $your_bank and read your password out loud to me on the phone, thank you!" You can't read out a passkey, nor can you read out a challenge to somebody that they are to sign with their passkey, because it's not possible by design.

afiori 2y ago

One big selling point of passkeys is that almost every workaround is impossible, whether that is good security or bad UX or both seems to be under discussion

lolinder 2y ago
If that's one of the big selling points then that's a problem, because workarounds are totally possible and actively implemented in the real world. As an obvious example: syncing passkeys is a workaround for their terrible UX that takes them further from the original design in ways that compromise some of the original security guarantees.
- wglb 2y ago
  Can you illustrate how workarounds to passkeys are being actively implemented?
  - fragmede 2y ago
    Password manager support. If my password manager running on my desktop can provision and access the passkey for use on another device like my phone, then so can malicious code running on my desktop, and exfiltrate it to hackers. The original design, where the private key only exists on a TPM and the private key never leaves the TPM doesn't have that flaw.
    - lxgr 2y ago
      Passkeys were always designed as being synchronizable and not necessarily be secure hardware backed. I think there’s a place for both of them in WebAuthN based on the security/availability/convenience tradeoff which will be different for every application. If you care about your users only using the trusted hardware, non-synchronizing kind, you have to use attestation anyway (or malware running on their device could create credentials that only appear to be backed by secure hardware). Unfortunately both Apple and Google seem to have unshipped their attestation support without replacement (they used to support hardware backed credentials in their devices too for a while) in the interest of not confusing users about what is and isn’t synchronized – now everything is.
      - wkat4242 2y ago
        Attestation would be terrible to have in passkeys because it will allow sites to block certain implementations. PayPal does this already by only allowing safari or chrome. With bitwarden on Firefox I'm locked out.
        lxgr 2y ago
        Yeah, as a user, I'm mostly happy about the lack of attestation. In an ideal world, only relying parties that really need it would request it, but views on who really does might obviously differ a lot between users and service providers. > PayPal does this already by only allowing safari or chrome. With bitwarden on Firefox I'm locked out. It works for me! However I do vaguely remember having to set them up on Chrome initially, but after that, they now work well even in Firefox. (Only on my computer; on my phone, I get an absurd non sequitur of "security keys only work on desktops").
        wkat4242 2y ago
        > It works for me! However I do vaguely remember having to set them up on Chrome initially, but after that, they now work well even in Firefox. (Only on my computer; on my phone, I get an absurd non sequitur of "security keys only work on desktops"). Oh ok, I haven't tried that. I don't even have Chrome installed anymore. And yeah I get that message too on my phone, even with standard FIDO2 MFA (not full passwordless Webauthn). Stupid because it does work just fine with other sites.

tptacek 2y ago

Passkeys are cryptographically phishing-resistant, and password managers just disable a convenience feature when a heuristic check fails. It's not the same thing. I don't care if you feel like the latter protection is sufficient for you or should be for others; they simply aren't the same, and that was what the comment upthread suggested.

lolinder 2y ago
Whether or not they're the same as a bit of a red herring, the question is whether the marginal added benefit of cryptographic phishing resistance is worth the trade-off in UX which introduces new kinds of vulnerabilities due to undesirable user behavior and/or implementation workarounds. And to answer that question you can't just dismiss the security offered by password managers—it's a very real protection that needs to be factored in to your assessment of the strengths and weaknesses of each system.
- tptacek 2y ago
  Take it up with the person who said the two countermeasures were literally equivalent. You're not going to get anywhere with me on this.
  - lolinder 2y ago
    Which user/comment are you referring to? The top-level comment? I'm the person you replied to initially, and that's not what I said, so I'm assuming you're referring to something else.
    - tptacek 2y ago
      passkeys stored in a password manager aren't any more secure in practical terms than random passwords stored in a password manager It is my contention that this statement is: 1. Categorical, 2. False, and 3. Categorically false
      - 2y ago

lxgr 2y ago

Not at all. One phishing vector is: (On a phone call) "Hi, this is $your_bank, please go to your password manager, open the entry for $your_bank and read your password out loud to me on the phone, thank you!" You can't read out a passkey, nor can you read out a challenge to somebody that they are to sign with their passkey, because it's not possible by design.