I would also like to see something to that effect. I feel that sometimes because SPAs use APIs, there's an unchallenged assumption that OAuth also has to be used with the in-browser code accessing those APIs. Even if the details are out of scope for this document, some text like the below at least gives a nod to the possibility of different approaches, which may ultimately be more secure and easier to mange. https://tools.ietf.org/html/draft-parecki-oauth-browser-based-apps-00#section-5.1 kinda does this too but I'm a +1 for a little something along the lines of what is being discussed recently in this thread.
On Mon, Dec 3, 2018 at 7:57 AM Aaron Parecki <aa...@parecki.com> wrote: > I support adding something to that effect, but would like to make it clear > that this removes the app from being covered under this BCP. How about: > > --- > Implementations MAY consider moving the authorization code exchange and > handling of access and refresh tokens to a backend component in order to > avoid the risks inherent in handling access tokens from a purely browser > based app. In this case, the backend component can be a confidential client > and can be secured accordingly. > > Security of the connection between code running in the browser and this > backend component is assumed to utilize browser-level protection > mechanisms. Details are out of scope of this document. > --- > > > > > On Mon, Dec 3, 2018 at 3:15 AM Torsten Lodderstedt < > tors...@lodderstedt.net <tors...@lodderstedt..net>> wrote: > >> Interesting. Even on this list people felt to see that moving some logic >> to a backend could solve some of the problems raised. What I want to convey >> is: the solution to a problem in the OAuth space does not necessarily need >> to be found on the OAuth protocol level. That’s a best practice in the same >> way as some OAuth pattern. >> >> What I’m suggesting is a statement in the BCP like >> >> — >> Implementations MAY consider to move authorization code exchange and >> handling of access and refresh tokens to a backend component in order to >> fulfill their security goals. >> >> Security of the connection between code running in the browser and this >> backend component is assumed to utilize browser-level protection >> mechanisms. Details are out of scope of this document. >> — >> >> > Am 03.12.2018 um 11:19 schrieb John Bradley <ve7...@ve7jtb.com>: >> > >> > This is my point. >> > >> > From a security perspective we have a server based confidential >> client.. The fact that it has a angular or other JS UI protected by a >> cookie seems to not be especially relucent to OAuth. >> > >> > Perhaps from the developer point of view they have a JS SPA and the >> only difference to them is in one case they are including the OAuth client >> and in the other they are using a server based proxy. So they see it as the >> same. >> > >> > Perhaps it is perspective. >> > >> > On Mon, Dec 3, 2018, 12:44 AM Aaron Parecki <aa...@parecki.com wrote: >> > In this type of deployment, as far as OAuth is concerned, isn't the >> backend web server a confidential client? Is there even anything unique to >> this situation as far as OAuth security goes? >> > >> > I wouldn't have expected an Angular app that talks to its own server >> backend that's managing OAuth credentials to fall under the umbrella of >> this BCP. >> > >> > ---- >> > Aaron Parecki >> > aaronparecki.com >> > >> > >> > >> > On Sat, Dec 1, 2018 at 11:31 PM Torsten Lodderstedt < >> tors...@lodderstedt.net> wrote: >> > the UI is rendered in the frontend, UI control flow is in the >> frontend.. just a different cut through the web app’s layering >> > >> > All Angular apps I have seen so far work that way. And it makes a lot >> of sense to me. The backend can aggregate and optimize access to the >> underlying services without the need to fully expose them. >> > >> > Am 02.12.2018 um 00:44 schrieb John Bradley <ve7...@ve7jtb.com>: >> > >> >> How is that different from a regular server client with a web >> interface if the backed is doing the API calls to the RS? >> >> >> >> >> >> >> >> On 12/1/2018 12:25 PM, Torsten Lodderstedt wrote: >> >>> I forgot to mention another (architectural) option: split an >> application into frontend provided by JS in the browser and a backend, >> which takes care of the business logic and handles tokens and API access.. >> Replay detection at the interface between SPA and backend can utilize >> standard web techniques (see OWASP). The backend in turn can use mTLS for >> sender constraining. >> >>> >> >>> Am 01.12.2018 um 15:34 schrieb Torsten Lodderstedt < >> tors...@lodderstedt.net>: >> >>> >> >>>> IMHO the best mechanism at hand currently to cope with token >> leakage/replay in SPAs is to use refresh tokens (rotating w/ replay >> detection) and issue short living and privilege restricted access tokens.. >> >>>> >> >>>> Sender constrained access tokens in SPAs need adoption of token >> binding or alternative mechanism. mtls could potentially work in >> deployments with automated cert rollout but browser UX and interplay with >> fetch needs some work. We potentially must consider to warm up application >> level PoP mechanisms in conjunction with web crypto. Another path to be >> evaluated could be web auth. >> >>>> >> >>>> Am 01.12.2018 um 10:15 schrieb Hannes Tschofenig < >> hannes.tschofe...@arm.com>: >> >>>> >> >>>>> I share the concern Brian has, which is also the conclusion I came >> up with in my other email sent a few minutes ago. >> >>>>> >> >>>>> >> >>>>> >> >>>>> From: OAuth <oauth-boun...@ietf.org> On Behalf Of Brian Campbell >> >>>>> Sent: Friday, November 30, 2018 11:43 PM >> >>>>> To: Torsten Lodderstedt <tors...@lodderstedt.net> >> >>>>> Cc: oauth <oauth@ietf.org> >> >>>>> Subject: Re: [OAUTH-WG] draft-parecki-oauth-browser-based-apps-00 >> >>>>> >> >>>>> >> >>>>> >> >>>>> >> >>>>> >> >>>>> On Sat, Nov 17, 2018 at 4:07 AM Torsten Lodderstedt < >> tors...@lodderstedt.net> wrote: >> >>>>> >> >>>>> > Am 15.11.2018 um 23:01 schrieb Brock Allen <brockal...@gmail.com >> >: >> >>>>> > >> >>>>> > So you mean at the resource server ensuring the token was really >> issued to the client? Isn't that an inherent limitation of all bearer >> tokens (modulo HTTP token binding, which is still some time off)? >> >>>>> >> >>>>> Sure. That’s why the Security BCP recommends use of TLS-based >> methods for sender constraining access tokens ( >> https://tools.ietf.org/html/draft-ietf-oauth-security-topics-09#section-2..2). >> Token Binding for OAuth ( >> https://tools.ietf.org/html/draft-ietf-oauth-token-binding-08) as well >> as Mutual TLS for OAuth ( >> https://tools.ietf.org/html/draft-ietf-oauth-mtls-12) are the options >> available. >> >>>>> >> >>>>> >> >>>>> >> >>>>> Unfortunately even when using the token endpoint, for SPA / >> in-browser client applications, the potential mechanisms for >> sender/key-constraining access tokens don't work very well or maybe don't >> work at all. So I don't know that the recommendation is very realistic. >> >>>>> >> >>>>> >> >>>>> >> >>>>> >> >>>>> CONFIDENTIALITY NOTICE: This email may contain confidential and >> privileged material for the sole use of the intended recipient(s).. Any >> review, use, distribution or disclosure by others is strictly prohibited... >> If you have received this communication in error, please notify the sender >> immediately by e-mail and delete the message and any file attachments from >> your computer. Thank you. >> >>>>> >> >>>>> IMPORTANT NOTICE: The contents of this email and any attachments >> are confidential and may also be privileged. If you are not the intended >> recipient, please notify the sender immediately and do not disclose the >> contents to any other person, use it for any purpose, or store or copy the >> information in any medium. Thank you. >> >>>> _______________________________________________ >> >>>> OAuth mailing list >> >>>> OAuth@ietf.org >> >>>> https://www.ietf.org/mailman/listinfo/oauth >> >>> >> >>> >> >>> _______________________________________________ >> >>> OAuth mailing list >> >>> >> >>> oa...@ietf..org <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 >> >> -- > ---- > Aaron Parecki > aaronparecki.com > @aaronpk <http://twitter.com/aaronpk> > > _______________________________________________ > OAuth mailing list > OAuth@ietf.org > https://www.ietf.org/mailman/listinfo/oauth > -- _CONFIDENTIALITY NOTICE: This email may contain confidential and privileged material for the sole use of the intended recipient(s). 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