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Passkeys: A shattered dream

fy.blackhats.net.au

381–390 of 789 posts

Re: Passkeys: A shattered dream

#381

Earlier quoted context omitted.

> Sure the do. All somebody needs is the password to your password manager. It's a single point of failure and by putting your passkeys in there to you've made it even more vulnerable. Not more vulnerable than if they were just using password. You're still missing my point, password managers do not give you the ability to just copy-paste the private key of a passkey into a form field, unlike passwords. Some don't giv…

I agree that it's not more vulnerable than just using a password, I'm only saying that it's only slightly less vulnerable under the best circumstances and incredibly more vulnerable under the worst circumstances (ie. if somebody got ahold of your password manager). I also agree that passkey-based authentication provides a smaller attack surface than purely password-based authentication. But putting the passkey on a s…

> I agree that it's not more vulnerable than just using a password, I'm only saying that it's only slightly less vulnerable under the best circumstances and incredibly more vulnerable under the worst circumstances (ie. if somebody got ahold of your password manager).

I feel like we might have a mismatch in understanding what a passkey is. You make a new keypair for each account to authenticate to. A leaked passkey is generally no more vulnerable than a password when leaked.

> But putting the passkey on a second device provides an even smaller attack surface since now a bad actor needs both your device (or a MITM attack) and your password.

Correct. The gold standard is a hardware secured, non-cloud synced private key.

> This is an HN forum. Nobody's giving "security advice,"

It's a technical forum with statements on a technical topic. Making statements like that can always be misinterpreted as technical advice by default.

> but I do feel like the parent comment's question hasn't been answered. Why would one store passkeys in their password manager instead of on a separate device?

This is fair. The answer is: convenience. It is most definitely worse security posture to sync passkeys than to store them on a separate, physical device that can answer challenges without leaking the private key.

The reason to use them over passwords is they are more secure, even when synced to a cloud vault.

Re: Passkeys: A shattered dream

#382
> when the room is in a country that has a list of travel advisories including "Violent crime is more common in the US than in Australia", "There is a persistent threat of mass casualty violence and terrorist attacks in the US" and "Medical costs in the US are extremely high. You may need to pay up-front for medical assistance".

What's wrong with these Aussie technocrats?

Re: Passkeys: A shattered dream

#383

I’ve avoided passkeys so far because I just don’t have a good mental model of them. All my passwords are randomly generate and stored in a password manager so I really haven’t felt the need to switch or felt constrained by my existing set up. I fully understand username/email + password and remembering the pain of things like “app specific passwords” makes me worry that some tools (open source, cli, etc) might not in…

> I’ve avoided passkeys so far because I just don’t have a good mental model of them. OK, so the simplest way to understand is to first know about the previous generation. U2F keys are designed to be used alongside a username and password, as a more secure replacement for phone apps showing 6-digit codes. In U2F the key has a hardware 'secure element' where secrets can't be extracted, even if you plug it into a compr…

Yubikeys absolutely took off in certain corporate, government and tech environments. Just not so much with the general public.

Re: Passkeys: A shattered dream

#384

The biggest issue with passkeys is that I just can't trust the companies offering them. They are locked into the platform for reasons that are ostensibly security but often indistinguishable from platform lock-in. If you make a passkey on an Apple device as far as I can tell it will never leave that device, ever, and there is no way to change this. Of course this means you can never be phished for your credentials bu…

Store your passkeys in BitWarden.

Because if you don't want to, it'll get in your way every time you try to use your actual passkey. Oh right, I forgot they added an option - now it just gets in your way every time you try to use your actual passkey on a new device.

Re: Passkeys: A shattered dream

#385

Earlier quoted context omitted.

The first time I log in to a service on a new device it'll prompt me to sign a challenge with a previous passkey. If I've got my yubikey handy I'll just plug it in and sign it and add a new passkey to my new device. If I only have my phone the site will flash up a QR code I scan with my phone which signs and posts back the proof to a callback URL for the site. I only need to do this once per device if I add a passkey…

Is the fact that you need access to an already- enrolled device to create additional passkeys part of the threat model that passkeys resolves, or just an annoying detail? And is this for every site, or just once per device? I can just look it up, this thread has been great to improve my mental model enough to start considering trusting it.

Its per-site. So the first time I log into GitHub on a new device, I need to do the handshake with another device. The first time I sign into Coinbase, I need to do the handshake with the other device.

So this typically means when I get a new device I'll have my Yubikey in a bag or something with me for a while and pull it out from time to time. Eventually practically every site I use gets enrolled on the new device and I never actually need to reach for the Yubikey or my phone or whatever.

I don't really make any concerted effort to go through each and every account when I get a new device, it'll pretty much just happen eventually. When I do sign up for a new account that supports passkeys I do try and make an effort make a passkey on at least two devices though, often at least whatever device I'm using to initially register and my yubikey. Then I'll make a point to log in sometime in the next few weeks on another computer and create a passkey there. Eventually I'll probably end up logging in and making passkeys on most of my devices.

Needing to auth with an existing passkey is a major part of the model. If you could just log in and create a new passkey with just a regular password, what's the point?

Re: Passkeys: A shattered dream

#386

The biggest issue with passkeys is that I just can't trust the companies offering them. They are locked into the platform for reasons that are ostensibly security but often indistinguishable from platform lock-in. If you make a passkey on an Apple device as far as I can tell it will never leave that device, ever, and there is no way to change this. Of course this means you can never be phished for your credentials bu…

The platform lock in attempt is wild, my initial experiences with Passkeys were great on iOS and Safari, either getting pushed to touch-id or scanning a QR with my phone. But then in Chrome I couldn't get into GitHub because chrome would only push me to use their manager and wouldn't offer a QR code. Seeing this more and more with Chrome, like Credit Card numbers used to just save and autocomplete in browser but then…

> and shut down my Google Pay account I never knew I had

Google loves that nonsense, don't they? It's as though they think so highly of themselves that they cannot imagine they might not be strictly doing us all a favor by signing us up for their services.

Fifteen years later, I still have friends occasionally sending messages to a GMail address I never asked for, never used, and didn't even know about for most of a year while it was virally spreading through people's address books, silently diverting mail away from my actual address. The only time I used this account, after I discovered that it existed, was to delete it - but GMail apparently still suggests it when people type my name, because I get an "oops, sent this to the wrong address" forward every few months.

No I will not be knowingly using any Google passkey service, but perhaps I will someday find that they have signed me up for it anyway.

Re: Passkeys: A shattered dream

#387

> At this point I think that Passkeys will fail in the hands of the general consumer population. Actually, I think it might be worse. The predators like Apple/Google have already pounced on passkeys as a consumer capture mechanism, so they'll ensure it doesn't fail.

They're a consumer capture mechanism insofar as password management tools are, and we want users to use those because they make security tolerable. The problem is that it turns out the OS vendor was in the best place to win the password management game.

Password management tools allow export.

Re: Passkeys: A shattered dream

#388

Earlier quoted context omitted.

But my password manager locks….requiring something stored in my brain.

Doesn't your password manager use biometrics to unlock though?

Not necessarily. I use bitwarden with a master password to unlock the vault.

Re: Passkeys: A shattered dream

#389

Earlier quoted context omitted.

But my password manager locks….requiring something stored in my brain.

Doesn't your password manager use biometrics to unlock though?

I stick with passphrases so nobody steals my retina or thumb.

Re: Passkeys: A shattered dream

#390

Earlier quoted context omitted.

> But they don't have the right to extract something from your brain. Most folks store passwords in password managers and don't use their brains to retrieve them.

password managers are growing, but I'm not sure that 'most' people use them. Maybe 'most' software engineers or techies, but the average person probably has no idea what a password manager is.

They may not know the name of a password manager, but many may know their iPhone remembers and fills in passwords.
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