Re: [OAUTH-WG] OAuth Security Topics -- Recommend authorization code instead of implicit

I am ok with that.

On Wed, Nov 28, 2018, 8:03 PM Torsten Lodderstedt <torsten@lodderstedt.net
wrote:

>
> > Am 28.11.2018 um 23:50 schrieb n-sakimura <n-sakimura@nri.co.jp>:
> >
> > That works.
>
> Good!
>
> I just realized this text has an issue with „token“ (only). It would allow
> „token“ to be used if the token would sender constrained. This completely
> ignores the fact implicit also shall be abandoned because of its
> vulnerability for access token injection.
>
> I therefore propose a modified text:
>
>    In order to avoid these issues, Clients SHOULD NOT use the implicit
>    grant. Furthermore, clients SHOULD only use other response types
> causing the authorization server to
>    issue an access token in the authorization response, if the particular
> response type detects access token
>    injection and the issued access tokens are sender-constrained.
>
> Or we just state:
>
>   In order to avoid these issues, Clients SHOULD NOT use the response type
> „token". The response types
> „token id_token“ and „code token id_token“ SOULD NOT be used, if the
> issued access tokens are not
> sender-constrained.
>
> >
> > In fact, I would further go and say MUST NOT but that probably is too
> much for a security consideration.
> >
>
> Mike suggested to go with a SHOULD NOT to get the message out but give
> implementors time to move/change.
>
> > Best,
> >
> > Nat
> >
> > Nat Sakimura / n-sakimura@nri.co.jp / +81-90-6013-6276
> >
> >
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> >
> > 差出人: Torsten Lodderstedt <torsten@lodderstedt.net>
> > 送信日時: 水曜日, 11月 28, 2018 11:38 午後
> > 宛先: n-sakimura
> > Cc: Dick Hardt; Hannes Tschofenig; oauth@ietf.org
> > 件名: Re: [OAUTH-WG] OAuth Security Topics -- Recommend authorization code
> instead of implicit
> >
> > Hi Nat,
> >
> >> Am 28.11.2018 um 21:10 schrieb n-sakimura <n-sakimura@nri.co.jp>:
> >>
> >> I would support
> >>
> >> 1) clearly defining Implicit as the flow that returns access token from
> the authorization endpoint ( some people confuses implicit as the flow that
> returns ID Token in the front channel)
> >
> > That’s the current text:
> >
> > In order to avoid these issues, Clients SHOULD NOT use the implicit
> >    grant or any other response type causing the authorization server to
> >    issue an access token in the authorization response.
> >
> > What would you like to modify?
> >
> >>
> >> 2) Banning the returning of the access token that are not sender
> constrained from the authorization endpoint
> >
> > In order to avoid these issues, Clients SHOULD NOT use the implicit
> >    grant or any other response type causing the authorization server to
> >    issue an access token in the authorization response, if this access
> tokens is not sender-constraint.
> >
> > What about this?
> >
> > kind regards,
> > Torsten.
> >
> >>
> >> Best,
> >>
> >> Nat
> >>
> >>
> >> Outlook for iOS を入手
> >>
> >> 差出人: OAuth <oauth-bounces@ietf.org> (Dick Hardt <dick.hardt@gmail.com>
> の代理)
> >> 送信日時: 水曜日, 11月 28, 2018 8:58 午後
> >> 宛先: Hannes Tschofenig
> >> Cc: oauth@ietf.org
> >> 件名: Re: [OAUTH-WG] OAuth Security Topics -- Recommend authorization
> code instead of implicit
> >>
> >> +1
> >>
> >> While there are various mechanisms to alleviate some of the issues of
> implicit, I don't think we can recommend specifics, and there may be future
> ones in the future. I think we all agree that implicit without any
> mitigation is problematic.
> >>
> >> How about we recommend against using implicit alone?
> >>
> >>
> >> On Mon, Nov 19, 2018 at 2:34 AM Hannes Tschofenig <
> Hannes.Tschofenig@arm.com> wrote:
> >> Hi all,
> >>
> >> The authors of the OAuth Security Topics draft came to the conclusion
> that it is not possible to adequately secure the implicit flow against
> token injection since potential solutions like token binding or JARM are in
> an early stage of adoption. For this reason, and since CORS allows
> browser-based apps to send requests to the token endpoint, Torsten
> suggested to use the authorization code instead of the implicit grant in
> call cases in his presentation (see
> https://datatracker.ietf.org/meeting/103/materials/slides-103-oauth-sessb-draft-ietf-oauth-security-topics-01
> ).
> >>
> >> A hum in the room at IETF#103 concluded strong support for his
> recommendations. We would like to confirm the discussion on the list.
> >>
> >> Please provide a response by December 3rd.
> >>
> >> Ciao
> >>
> >> Hannes & Rifaat
> >>
> >>
> >>
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