FTR the "Proof of possession" relies on a (specific) random number being received from a device.
It won't be long before that hardware device that is supposedly being held by a person becomes a soft device, which will then be impersonated.
It won't be long before that hardware device that is supposedly being held by a person becomes a soft device, which will then be impersonated.
There's a number of problems with the idea:
- The device (eg. Phone or Tablet) gets owned and gives up its value as a provider of confirmation
- Users end up nominating a password service like 1Password as the device
- Someone manages to convince the authentication systems that their faux device emitting the signal, is the device in question
For the second point, when I was integrating a (FOSS) passkey system into a product, it drove me up the wall having to have my phone right next to me every time I was working. I ciouldn't leave it in the next room on charge, for example.
As a user I drew no comfort from the system, and viewed it as a burden, and was concerned about replacing the device in the event of a loss/theft or destruction - which is usually the pathway malicious individuals take to insert their device as the one to be used instead of the original.
At a certain point, the user behavior IDS constraints become more important than building a deeper moat. 2FA cellphone based anything is $23 away from some adversaries control... ultimately more security theater in my opinion YMMV =3
Any device could get exploited. The requirement that it happen to both that device and my computer, simultaneously, significantly raises the difficulty bar.
> Users end up nominating a password service like 1Password as the device
I don't see the issue. Isn't that the user's choice to make? If you want better security then don't make that particular choice.
> Someone manages to convince the authentication systems that their faux device emitting the signal, is the device in question
By that logic why have passwords or keys or anything at all? Someone might exploit the server and get in regardless so why bother?
I've got at least a few objections to modern auth schemes but these aren't them.
Yes.
> The requirement that it happen to both that device and my computer, simultaneously, significantly raises the difficulty bar.
Well, only one of the two devices needs to be exploited. There's twice the attack surface for you.
> I don't see the issue. Isn't that the user's choice to make? If you want better security then don't make that particular choice.
Sure, and allowing people to use "password" as their password is bad, but the design of this system encourages using a "cloud" device, because of the issues already pointed out.
> By that logic why have passwords or keys or anything at all? Someone might exploit the server and get in regardless so why bother?
The system has added nothing that makes passwords or keys more secure.
> I've got at least a few objections to modern auth schemes but these aren't them.
/me shrugs
I'm almost at the point of caring.
I think we must be thinking of very different things here. Maybe I misunderstand the scheme you're objecting to. Would you mind elaborating?
Perhaps what you had in mind are the PoP tokens from RFC 7800? (Sure would be nice not to play guessing games though.) Given that those are intended to replace OAuth bearer tokens they are quite a decent upgrade from a security perspective. Used with a purely software based password manager it is no longer enough to simply exfiltrate a token from the browser. Used with TPM backed keys it is approximately equivalent to the chip in a bank card.
Because I get to talk to people that actually understand technical discussions.
> How could I possibly demonstrate lack of understanding when you actively avoid clarifying what you're even talking about in the first place?
You came into the thread with no understanding, then some time later decided to play word games.
All of the rest of your contributions from now are going straight to /dev/null where they belong.
As I already stated I'm no longer certain what scheme we're actually taking about. Is there some reason you don't feel like elaborating?
For my part I thought we were taking about a proof of possession scheme in addition to regular auth. The "regular auth" scheme was unspecified so could be password, software based TOTP, hardware token, whatever.
Widespread proof of possession already exists in the form of chips in bank cards. It seems to be quite resilient to attack in practice.
Even if I use software on my phone for proof of possession you still have to compromise the computer I'm actually logging in with, no? So the attack surface is either the same (primary device) or increased (primary plus secondary, simultaneously) depending on various practical details regarding implementation and usage.
If the "regular auth" scheme involves a half decent hardware token then good luck compromising that remotely. I won't be betting in your favor.
You don't need anything special to do that. Just select a hardware token that refuses to sign anything until it receives physical input from you.