I think the problem here for me is that lack of clarity of how this problem could be better constrained at the protocol level. As far as I can see, albeit naively, the problem is purely an internal implementation detail. Is that not the case? Is there really something missing in the grants that would encourage AS to do the right thing? If so, can you share, because I'm not seeing it.
That being said, even if it is an implementation detail, that doesn't mean there couldn't be some sort of BCP. On Tue, Aug 15, 2023 at 7:42 PM Rodrigo Speller <rspeller= 40primosti.com...@dmarc.ietf.org> wrote: > I read all the comments carefully while flying through Brazil, and I > confess that my reasoning from the beginning tended to say that the OAuth > trust model is “as is” and that the main point of the trust relationship is > between the AS and the RO (in this case, a user). > > At various times, while reading, I agreed that Matthias' question was > about a problem that would not fit directly into the OAuth Framework, as I > understood that the central point in question was authentication and not > authorization. But I refused to accept that my point of view would be > correct due to the avalanche of exposed reasoning that contributed to my > understanding and that even so, Matthias insisted on making himself > understood by different approaches, leading to believe that he understood > the answers, but still did not was convinced that we had understood this > problem in essence. > > So, during the flight, I reflected on Matthias' insistence: "What could we > be missing?" Brilliantly, I think Matthias raised a very important and > fixable point: “That the user MUST allow the connection on both sides on > the client and on the provider.” > > As is known here, OAuth 2.0 is not a ready-to-use protocol, but a > framework that is constantly evolving, it is specified by multiple RFCs and > its main implementation is the OpenID Connect 1.0 layer, which is also > under development. I say this because I believe the solution to this point > raised by Matthias would result in a Zero-Trust Authorization Grant with > great value to the protocol, as it would reinforce user authorization so > that the AS could authorize client applications. > > In this grant type, the AS would ask the user to sign evidence tokens to > authorize client application access in the authentication/consent phase. Of > course, this flow would require some restrictions to maintain a high degree > of security, such as: Generation and storage of user signature keys; Form > of registration of the signature verification key with the AS; Transport of > authorization evidence to the client application; Transporting the evidence > token signature verification key to the client application; etc; > > I believe that a Zero-Trust Grant Type with a model similar to the one > above would be very useful for Web 3, financial applications (FAPI / Open > Banking), etc. It would also encourage the use of private keys to > authenticate users in these environments, making room for the signing of > operational tokens in the future (out of scope). > > Therefore, I ask Matthias to validate and complement, if possible, my > point of view. And I invite this group to start an effort to draft this > Grant Type with me. > > > Em qui., 10 de ago. de 2023 às 22:21, Michael Jones < > michael_b_jo...@hotmail.com> escreveu: > >> I HIGHLY recommend the authoritative blog post on the subject “OAuth 2.0 >> and Sign-In”, written by a dear friend to many of us, Vittorio Bertocci, >> just over a decade ago. While Microsoft took it down, it lives on in the >> Wayback Machine at >> http://web.archive.org/web/20130105031040/http://blogs.msdn.com/b/vbertocci/archive/2013/01/02/oauth-2-0-and-sign-in.aspx >> <http://web.archive.org/web/20130105031040/http:/blogs.msdn.com/b/vbertocci/archive/2013/01/02/oauth-2-0-and-sign-in.aspx>. >> It authoritatively covers much of the ground in our current discussion. >> >> >> >> Read and enjoy! >> >> >> >> -- Mike >> >> >> >> *From:* OAuth <oauth-boun...@ietf.org> *On Behalf Of * Dick Hardt >> *Sent:* Thursday, August 10, 2023 5:46 PM >> *To:* Matthias Fulz <mf...@olznet.de> >> *Cc:* oauth@ietf.org >> *Subject:* Re: [OAUTH-WG] OAuth Trust model >> >> >> >> Sorry -- I have not read this thread in depth, so if you have another >> crisp example, please send. >> >> >> >> Your description sounds like an identity problem and not an authorization >> problem. OAuth solves the latter, and it is a feature that the RS does need >> to know the client, only that the client is authorized. >> >> >> >> To fit that into your analogy, anyone the school deems authorized to pick >> up the kid is authorized to pick up the kid. If you don't like how the >> school decides that, don't send your kid to that school, or work to change >> the school's policy. >> >> >> >> >> >> >> >> On Thu, Aug 10, 2023 at 4:41 PM Matthias Fulz <mf...@olznet.de> wrote: >> >> I'm running out of ideas to get the point explained... >> >> Ok let's try it from an abstract view: >> >> Think about a school where your kid is allowed to get picked up by a >> legitimated list of persons -> ok >> >> Now think about the school saying I'm trusting a third party about >> identifying any person on that list, without asking the person about that >> this third party is allowed to identify this person. >> >> The problem is, that by design the person who's identity is to be >> verified has no control about what AS is allowed by the site to verify the >> identity. >> >> >> >> Sorry for that stupid example but I'm really not able to explain the >> issue in another way anymore :( >> >> On 8/11/23 00:02, Dick Hardt wrote: >> >> This sentence does not make sense to me "which AS is AUTHORIZED at which >> RS acting as the user" >> >> >> >> The RS server has delegated authorization decisions to the AS >> >> >> >> The client is acting as the user >> >> >> >> On Thu, Aug 10, 2023 at 2:59 PM Matthias Fulz <mf...@olznet.de> wrote: >> >> I can follow your point but please try to think from a different >> perspective: >> >> As authorization protocol, how can it not let the user decide which AS is >> AUTHORIZED at which RS acting as the user? >> >> >> >> On 8/10/23 23:28, Dick Hardt wrote: >> >> "auth providers" is an extremely confusing term. >> >> >> >> OAuth has no involvement in the content an RS provides the client -- the >> AS only provides authorization to access the content at the RS. >> >> >> >> It is common that the AS and RS are the same entity, but the protocol is >> designed to have a separation of concerns so that they are acting >> independently. >> >> >> >> From what I can understand in your discussion, you are wanting OAuth to >> do something it is not designed for. >> >> >> >> >> >> On Thu, Aug 10, 2023 at 2:03 PM Matthias Fulz <mf...@olznet.de> wrote: >> >> >> >> On 8/10/23 10:25, Warren Parad wrote: >> >> You've lost me at this: >> >> >> >> Some site, which I'm registered in is trusting some oauth provider I'm >> not even knowing about. I'm not registered at this provider. If this >> provider is (independent how or from whom) is used in a malicious way, they >> can access my account, without my knowledge by sending a valid token >> including my email. >> >> >> >> Nothing stops a site you are using, registered with your email address, >> from just selling your data to a third party, or blanket publishing it >> publicly. There is nothing we can do to stop this unless the data we care >> about is encrypted on the client side. OAuth doesn't really have anything >> to do with it. >> >> Yes but that's the point: The site itself has to do it. If they are not >> willing to it's ok. >> >> But: With the actual concept using auth providers, even if the the site >> is NOT willing to sell it, my account could be accessed by using the >> trusted auth provider without the site itself needs to do anything. And the >> problem is, that such sites wouldn't be technically forced to use such auth >> providers by active permission granting from user side. >> >> That's the difference I'm trying to point at. >> >> Sorry I'm really struggling to explain it in another way (will think >> about). >> >> >> >> Because it has nothing to do with OAuth, the suggested solution of course >> must have a hole with it. And indeed it does. What if the site offers the >> token strategy, but then decides to outsource the whole authentication >> process to a different third party? We are back at the same problem again. >> However it sounds like what you are saying is that there should be a >> standardized mechanism for handling the site <=> user token verification. >> If we use OAuth terminology that would be: We should allow *step-up >> authentication* to occur solely between the *resource server (RS)* and >> the *user agent* without involving the *authorization server (AS)*. But >> then who generates the new JWTs? If the AS generates the new one then, we >> didn't stop anything. And if the RS generates the new one then actually the >> AS isn't needed to do anything. >> >> No that's not what I was suggesting. >> >> It's not about excluding the authorization server it's more about a >> additional verification, that the user is granting the RS explicit >> permission to use the AS on behalf. >> >> AFAIK the actual situation is the following: >> >> The site is providing the login via AS and the AS can then on behalf any >> user of this site just login. The site can of course implement some >> permission granting but that's not required. This is done via signed JWT, >> etc. which are verified on the RS side. >> >> Now my suggestion would be more like adding an additional verification >> before the AS can be used: >> >> *The following is just some rough idea on how to add such verification in >> a safe way* >> >> The RS side will use a signed jwt that will be included into the access >> token send from AS to verify that the user has granted permission to use >> this AS. >> >> This could be done automatically during registration, so it wouldn't >> break this feature in a way that the RS will create this token during >> registration and send it to the AS. The AS will need to include this token >> for requests and if this cannot be verified on the RS side it will not be >> accepted. >> >> Further (ae. existing accounts) the user could provide a signed jwt to >> the AS and a pub key to the RS. If the jwt cannot be verified than the user >> did not granted the permission to use the AS on behalf. >> >> >> >> For companies, etc. using RS / AS on premise this could all be >> implemented to be done automatically and it would not create any additional >> effort on administration side. >> >> >> >> And that latter case is actually the reality if we consider these tokens >> to be a 2FA mechanism that is managed by the site/resource server. So I >> read this as, we should standardize *WebAuthn *communication between a *user >> agent* and the *resource server. *That already exists though, doesn't it? >> >> Yes and no: Think about the widely used TOTP (ae. github) the Secret Key >> is created on the AS side and therefore under full control of it. This is >> not helping to protect the user from malicious intents. >> >> >> >> >> >> On Thu, Aug 10, 2023 at 12:59 AM Matthias Fulz <mf...@olznet.de> wrote: >> >> I'm trying to explain my concern more deeply, please try to follow my >> thinking. >> >> First: Everything you've written is correct and I fully agree. >> >> But: The difference is: I'm deciding, that I'm using email from xy, I'm >> deciding, that I'm using this email to register at some site or anything. >> >> Anything of these services could be hacked of course, and then they can >> use my mail to reset password, use the accounts, etc. >> >> Now think from the other side: >> >> Some site, which I'm registered in is trusting some oauth provider I'm >> not even knowing about. I'm not registered at this provider. If this >> provider is (independent how or from whom) is used in a malicious way, they >> can access my account, without my knowledge by sending a valid token >> including my email. >> >> >> >> I'm not sure how to explain the main concern about this in more detail >> and of course I can avoid services providing these type of logins without >> my permission, but as said what about the future? >> >> On 8/10/23 00:40, Warren Parad wrote: >> >> Let me try that differently, is OAuth more vulnerable than email usage? >> If you hacked any email provider that's arguably a bigger goldmine than >> just ones protected by oauth. As long as sites are protected by email, >> oauth gives a more secure strategy. Most providers that accept email as >> authentication allow you to reset your password via email. >> >> >> >> Going further, "email is insecure" because providers that send email can >> impersonate you. How about telecom companies, they can pretend to send SMS >> from you. Or the government, they could issue a new password in your name >> and pretend to be you. The horror. >> >> >> >> In all seriousness, it's about your threat modal more than anything. >> Concerned about your email, then that's your weak point, concern about >> oauth, we'll first be concerned about your email, and then you can be >> concerned about oauth. >> >> >> >> If we assume that everything was on oauth, then there's the question of >> why don't providers just implement a FIDO2 compliant strategy. Wouldn't >> that solve everything? >> >> Don't get me wrong: I'm not telling everything is on oauth as far (I'm >> not so deep into the protocol) it's acting only as authorization not as >> authentication, than it is anyway the wrong point to address this issue. >> >> But if it would be possible to eliminate this specific issue inside the >> protocol directly, it would be the best solution to not even run into this >> situation at any later point of time. >> >> >> >> As total naive approach I could about something like: >> >> Client is trusting Provider for user authentication/authorization >> >> Client must set some random verification token (normally requested / set >> by the user) >> >> User is registering this token under the provider >> >> Only if this token is valid the token is accepted by the client >> >> >> >> If something like this would be included in the protocol itself, it would >> be working in all situations like companies because they can control both >> sides and generate such tokens automatically >> >> And yes if the site is working together with the provider than it's over, >> but that's exactly the point: Than the target itself must be included not >> only the single provider, where the user might not even have an >> relationship with. >> >> >> >> Further I could think of extended security, by using signed tokens with >> user provided public key, so it's technically secured to just fake tokens. >> >> >> >> On Thu, Aug 10, 2023 at 12:27 AM Matthias Fulz <mf...@olznet.de> wrote: >> >> Thank you for the responses so far. >> >> On 8/9/23 22:20, Warren Parad wrote: >> >> I can tell you I definitely read it. I actually read it multiple times. >> But I don't know what to tell you. The problem you've identified exists, >> but that doesn't necessarily mean it is a problem. In a way it is a bit >> like, You create a bank account at a bank and you give them all your money. >> They then decide to never give it back. >> >> Yep I know, but the difference is, that I've full control over my >> decision to give my money to this bank or not. >> >> >> >> While banks are regulated in most countries and things like GitHub are >> not, in essence this interaction is based on trust. Of course solutions >> like WebAuthn via FIDO2 used as a first party authentication can solve >> this, and arguably this is the remit of the entire web3.0 domain. >> >> >> >> I don't think anyone would suggest this isn't a problem, just that it >> isn't that big of a problem. I think realistically, in order for this >> problem to have a closed form solution, it would need to start with a >> suggestion on how to solve it, rather than a bunch of us agreeing that it >> is. Because right now there doesn't seem to be any fundamental solution >> available for this. And honestly, the bigger problem is the digital assets >> at risk at the third parties is not due to impersonation, but just general >> negligence. GitHub isn't trying to malicious log into my StackOverflow >> account, and Google isn't trying to log into my bank. That's because these >> organizations have supposedly bound themselves to not grant this ability to >> their internal engineers to abuse. And they are spending tons of resources >> attempting to stop external attackers. >> >> >> >> That being said, it's hard to know if this problem hasn't already >> transgressed in the wild. While it is certainly possible, it seems internal >> users are more likely to act maliciously on behalf of the user via their >> owned data in their own company, rather than attempt to impersonate their >> users at third party sites. >> >> These points are totally correct, but I think also about something like >> official Authorities (ae. Patriot Act, etc.) that would definitely be >> interested in such things (ok not on me personally), but this is another >> topic. >> >> For me to be more safe, I'm using now a unique mail for Github, etc., >> which is sufficient for now, but if you think into the future and >> especially about oauth with more than a handful widely used trusted >> Providers and that they could be hacked, infiltrated forced to grant >> malicious access, etc. Than this could become to a huge problem in no time. >> >> As example: Think about one widely used trusted provider that's hacked, >> or similar. You could access so many accounts on multiple sites, even if >> the users are never used this oauth for these sites. >> >> >> >> Sorry to insist here, but just because it is not an issue now, I can't >> agree that this not a big deal in general. >> >> I mean in the above scenario even a unique mail wouldn't help because >> that could send any mail, they want to these sites. Think about such >> provider acting malicious and you would not even HAVE an account at any of >> them: every site, that trusts them could be accessed under your account >> just by knowing the user identifier, which is in 99% time the mail. >> >> >> >> - Matthias >> >> >> >> - Warren >> >> >> >> On Wed, Aug 9, 2023 at 10:06 PM mfulz <mf...@olznet.de> wrote: >> >> Anyone read this topic or could tell if there is a better place to adress >> this? >> >> >> >> Sent from Nine <http://www.9folders.com/> >> ------------------------------ >> >> *Von:* mfulz >> *Gesendet:* Sonntag, 16. Juli 2023 03:38 >> *An:* oauth@ietf.org >> *Betreff:* [OAUTH-WG] OAuth Trust model >> >> >> >> >> >> Hi Together, >> >> I was thinking about some (at least I see it in that way) problem in the >> whole oauth/openid design: >> >> The problem is the following: >> >> The user has no control about what providers are accepted by the clients >> (websites, etc.) and this opens access to these providers without any way >> to protect against that. >> >> Example: >> >> I've created an account with email/password login at stackoverflow >> >> I've created an account with the same email at github >> >> -> logged out from stackoverflow >> >> -> logged in via github oauth -> working and connected to the email/pw >> account from stackoverflow >> >> >> >> Stackoverflow has the possibility to remove the github login now, but the >> main problem is, that I would be out of control, that some of these oauth >> providers >> >> (please don't go into the discussion WHY they or anyone should do it) >> could access my accounts, when such site would allow them as provider. >> >> >> >> In my opionion it would be good to avoid such issues, by including >> something in the standard, that the user MUST allow the connection on both >> sides on the client >> >> and on the provider. >> >> >> >> Yes for sso without any existing account that's some kind of an issue, >> but still it could be added some verification process like sending >> confirmation link >> >> That the user is accepting the oauth provider on the Client side. >> >> Then the oauth provider would also need access to my emails to access my >> account. >> >> >> >> Not sure if I'm wrong here but I think my description is correct. >> >> >> >> BR, >> >> Matthias >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> > _______________________________________________ > OAuth mailing list > OAuth@ietf.org > https://www.ietf.org/mailman/listinfo/oauth >
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