Re: [OAUTH-WG] WGLC for Step-up Authentication

[Rifaat Shekh-Yusef <[e-mail]>]

Jaimandeep,

With the chair hat on, and as the shepherd for this document, I think that
the authors addressed your comments in detail, and Warren provided you with
some valuable responses. I do not see a need for any further discussion at
this stage.

The next step is the shepherd review, which could start a new discussion
about this document.

Regards,
 Rifaat


On Tue, Oct 25, 2022 at 2:11 PM Jaimandeep Singh <jaimandeep.phdcs21=
[e-mail]> wrote:

> Dear Warren,
>
> It is always nice to read your elaborately written views. It helps in
> getting perspective.
>
> I have a slightly different take on the subject. What is the client
> application going to do with the "acr_values"? Ultimately, it is going to
> send these values to the authorization server in order to meet the required
> end-user authentication criteria. This is what I am referring to as reverse
> flow RS->client_app->AS.
>
> I'm on the fence of calling the "user agent" untrusted.
>
> Here we have to consider client applications that are other than browsers
> such as native apps and these apps can surely be called "untrusted". These
> native apps will first receive the "acr_values" from the RS and will then
> use the "user agent" to pass the values to the authorization server.
>
> I'd ask for at least one practical attack that this RFC enables (not
>> necessarily causes).
>
>
> Well I will start at the abstract level first. Wherever the trust
> boundaries are crossed it results in security complications. Here the data
> is moving from trusted (RS)->untrusted (client-app)->trusted(AS). Now,
> coming to specific examples,
>
> Example 1: OWASP Top10: API8:2019 Injection. Once the client_app presents
> the "acr_values" data to the authorization server it has to be sanitized,
> otherwise it can result in unintended command execution.
>
> Example 2: OWASP Top 10: API1:2019 Broken Object Level Authorization.  The
> client_app will use all possible combinations of "acr_values" to know the
> behaviour of the particular authorization endpoint/server.
>
> On Tue, Oct 25, 2022 at 5:23 PM Warren Parad <[e-mail]> wrote:
>
>> I'm glad that we can move on from item No 1. Regarding this second one,
>> the AS is not required to be involved in this communication, as the RS
>> already has the capability to convey to the user agent why the access token
>> is denied. It just hasn't been standardized. There are lot's of reasons why
>> an access token or the user identity the token is for might not contain the
>> necessary authorization to access to the resource. I see here we are only
>> codifying that communication rather than opening any holes.
>>
>> What's the reason for needing to sign data from the RS, the RS might not
>> even be a client of the AS, so if theoretically necessary, we would have to
>> challenge our suggested implementation. Is there a specific security
>> problem you are thinking about?
>>
>> I'm on the fence of calling the "user agent" untrusted. Sure it is, but
>> the browsers have the expectation to expose the requests from the RS to the
>> user, if we blindly passed the acr_values from the RS directly to the AS
>> then there would be a problem, but signing the values wouldn't change
>> anything. In any case the user agent/client application can't be agnostic
>> to the acr_values because updating the acr actually does require user
>> input. While the user agent the user is using to interact with the RS might
>> not be the same one used for the AS in the acr needed value, for instance
>> the hypothetical SMS, still there is a user interaction.
>>
>> I'm not seeing any security issue here, and while exposing data to a
>> malicious attacker is always a concern, this is opt-in functionality by the
>> RS, so if they are concerned they need not implement the RFC. I'd ask for
>> at least one practical attack that this RFC enables (not necessarily
>> causes).
>>
>> On Tue, Oct 25, 2022 at 1:29 PM Jaimandeep Singh <
>> [e-mail]> wrote:
>>
>>> Dear Warren, Brian and Vittorio,
>>> My concerns regarding the additional complexity are well addressed by
>>> Warren. I am reproducing the same for sake of records in the email archive.
>>>
>>>> I'd love to see a situation where it is a better at the gateway level.
>>>> The problem is that, even if you could, you almost certainly shouldn't,
>>>> since doing so couples the gateway to the authorization check/permissions
>>>> validation of the service. The gateway now needs to become away of how the
>>>> underlying resources work.
>>>
>>> Even in simple scenarios, this becomes impossible to manage since
>>>> understanding the "business logic" is required to know "whether a user
>>>> should have access". That means the gateways are doomed from the start.
>>>
>>> As I mentioned it is possible, doing the check at the component level
>>>> can be augmented by a system that manages those permissions, which
>>>> different from doing the check at the gateway level. At least this is what
>>>> we advice the clients of our CIAM solution.
>>>
>>>
>>> I would like to close the concerns regarding Item No-1 and move on
>>> towards Item No 2. I am reproducing the conversation for sake of ease of
>>> reference.
>>>
>>> *Item No 2*: Punching a security hole by requiring AS to act on
>>> information provided by the client applications (Reverse Flow).
>>> *Follow-up Comments-v2*. Refer Section abstract of draft RFC
>>>
>>>> This document also codifies a mechanism for a client to request that an
>>>> authorization server achieve a specific authentication strength or
>>>> freshness when processing an authorization request.
>>>
>>>
>>> a. In our journey of OAuth 2.0 we are still struggling with security
>>> issues related to access tokens from AS->clientapp->RS. Now, we are
>>> introducing a reverse flow, which is likely to introduce numerous other
>>> vulnerabilities. Whenever the communication crosses the boundaries from
>>> trusted -> untrusted -> trusted it creates its own set of security
>>> problems.
>>> b. Need for signing the values (error_codes) returned by the RS which
>>> can be verified by the AS. Therefore, we need to look at ways by which the
>>> RS returns a signed JWT token containing "acr_values" or other such
>>> parameters which are opaque to the client applications. I also appreciate
>>> that signed JWT will create its own complexities especially with regards to
>>> verifying the association between the RS and its public key.
>>>
>>>
>>> On Mon, Oct 24, 2022 at 6:18 PM Jaimandeep Singh <
>>> [e-mail]> wrote:
>>>
>>>> Dear Warren,
>>>> It seems reasonable to handle items one by one in order to reach
>>>> convergence. I am taking up Item No1 in this email to achieve convergence
>>>> and close the same. The previous suggestions can be referenced at
>>>> part-1
>>>> <https://mailarchive.ietf.org/arch/msg/oauth/rNqEACxVM1OtDfT5SIQDybSK6kk/>,
>>>> part-2
>>>> <https://mailarchive.ietf.org/arch/msg/oauth/U8c9JfHCnmcbX238zXWTuRgx2BE/>
>>>> and part-3
>>>> <https://mailarchive.ietf.org/arch/msg/oauth/SsollGVV01oPmYYTef25-SYVYok/>
>>>> .
>>>>
>>>> *Item No 1*: Striking at the core of OAuth 2.0 idea by coupling end
>>>> user authentication with authorization.
>>>> *Follow-up Comments-v3*. My original concern was the introduction of
>>>> tight coupling between end user authentication and the OAuth 2.0. It was
>>>> explained by Brian that the draft RFC does not intend to introduce any
>>>> coupling and just provides a channel of signal/information flow between AS
>>>> and RS via client app. It is just that the signal as of now only contains
>>>> data on the end-user authentication. This seems to be a
>>>> reasonable explanation and the point is not pressed further. However, this
>>>> has raised two sub concerns. One is mentioned in Item No5, so I am not
>>>> taking it up here.
>>>>
>>>> The other remaining sub concern is the complexity introduced due to the
>>>> introduction of the new channel. If we look from the higher level of
>>>> abstraction, earlier the events concerned were handled at the
>>>> interface/entry level, now the information about the events is passed on to
>>>> the other components of the system . All the other components may handle
>>>> the events as per their policies and can be out of sync with each other.
>>>>
>>>> Coming back to OAuth 2.0, earlier the authentication complexities were
>>>> handled by AS as per OIDC specs. Now, with the introduction of this
>>>> channel, the authentication event information is being passed on to the RS.
>>>> The requirement/behaviour of RS may not be in sync with the requirements of
>>>> AS. I had given a hypothetical example of one such complexity in my email
>>>> part-3. Just to give another flavour of the complexity I am quoting from
>>>> Section 5 of the draft RFC which acknowledges the existence of loops being
>>>> handled by OIDC specs.
>>>>
>>>> The recommended behavior will help prevent clients getting stuck in a
>>>>> loop where the authorization server keeps returning tokens that the
>>>>> resource server already identified as not meeting its requirements hence
>>>>> known to be rejected as well.
>>>>
>>>>
>>>> If the esteemed members are of the view that the benefits accrued are
>>>> more than the complexity introduced we can close the concern and move
>>>> ahead. I would request the members to give their views.
>>>>
>>>>
>>>> On Mon, Oct 24, 2022 at 3:51 PM Warren Parad <[e-mail]> wrote:
>>>>
>>>>> I get the sense we are diverging from a resolution to your questions
>>>>> rather that converging on one.  Given that some of the items reference each
>>>>> other, would it be possible for you to prioritize which item you are most
>>>>> concerned with? Then we could work through that one and then move on to the
>>>>> next point. By this email I'm now lost on the current issues with the spec
>>>>> from your perspective which makes it hard, at least for me, to continue
>>>>> this conversation.
>>>>>
>>>>> Is item 1 the primary concern you want to discuss or is it something
>>>>> else?
>>>>>
>>>>> On Mon, Oct 24, 2022, 07:52 Jaimandeep Singh <
>>>>> [e-mail]> wrote:
>>>>>
>>>>>> Dear Brian, Warren and Vittorio,
>>>>>>
>>>>>> Thank You for taking out time and efforts in giving the detailed
>>>>>> explanation. After spending considerable time on the explanations provided,
>>>>>> my follow-up comments are given below for the considered view of the
>>>>>> esteemed members. The original comments are at part1
>>>>>> <https://mailarchive.ietf.org/arch/msg/oauth/rNqEACxVM1OtDfT5SIQDybSK6kk/>
>>>>>> and part2
>>>>>> <https://mailarchive.ietf.org/arch/msg/oauth/U8c9JfHCnmcbX238zXWTuRgx2BE/>
>>>>>> .
>>>>>>
>>>>>> *Item No 1*: Striking at the core of OAuth 2.0 idea by coupling end
>>>>>> user authentication with authorization.
>>>>>> *Follow-up Comments-v2*.
>>>>>>
>>>>>>> by allowing a resource server to signal to a client that the
>>>>>>> authentication event associated with the access token of the current
>>>>>>> request doesn't meet its requirements (however the RS determines that) and
>>>>>>> convey that to the AS in the authorization request (via the user's browser)
>>>>>>> to remediate.
>>>>>>
>>>>>> In my view we are creating an information/signal channel between AS
>>>>>> and RS via client app. Both AS and RS may or may not act on this
>>>>>> information/signal depending upon their policies and is out of the scope of
>>>>>> the draft RFC. The forward path of this information/signal channel can
>>>>>> piggyback on the existing mechanism of the access tokens. However, no such
>>>>>> mechanism exists for the reverse path from RS to AS in the OAuth 2.0 specs.
>>>>>> The question then arises:-
>>>>>>
>>>>>> a. Do we need to restrict the signals only to the end user
>>>>>> authentication or are there any more signals to be considered. This
>>>>>> question was previously asked by Yusuf. I have suggested other options in
>>>>>> Item No 5 of this email.
>>>>>>
>>>>>> b. Are we comfortable in opening up a reverse channel from RS to AS
>>>>>> via client app which will potentially open OAuth 2.0 to numerous other
>>>>>> vulnerabilities as mentioned in Item No 2.
>>>>>>
>>>>>> c. These signals are already well handled at the entry point i.e AS
>>>>>> level through various specs like OIDC. Then, is there a need to again send
>>>>>> these signals to RS and then carry the response back to AS? Is this not
>>>>>> overly complicating the OAuth process? A hypothetical example of such a
>>>>>> complication is given below.
>>>>>>
>>>>>> Hypothetical example. Say tomorrow the draft RFC is implemented and
>>>>>> now a particular RS decides that its high value scopes can only be accessed
>>>>>> by end-users authenticated using MFA. This may result in a scenario
>>>>>> wherein, the end-user is not able to read his own emails if he does not
>>>>>> have MFA enabled. Alternatively, he may be locked out, in case the email
>>>>>> client application used by him does not support MFA. The concept of
>>>>>> "freshness!!" may result in the requirement of logging in every hour or
>>>>>> every day for accessing own emails.
>>>>>>
>>>>>> *Item No 2*: Punching a security hole by requiring AS to act on
>>>>>> information provided by the client applications (Reverse Flow).
>>>>>> *Follow-up Comments-v2*. Refer Abstract of draft RFC
>>>>>>
>>>>>>> This document also codifies a mechanism for a client to request that
>>>>>>> an authorization server achieve a specific authentication strength or
>>>>>>> freshness when processing an authorization request.
>>>>>>
>>>>>> In our journey of OAuth 2.0 we are still struggling with security
>>>>>> issues related to access tokens from AS->clientapp->RS. Now, we are
>>>>>> introducing a reververs flow, which will itself introduce numerous other
>>>>>> vulnerabilities. Whenever the communication crosses the boundaries from
>>>>>> trusted -> untrusted -> trusted it creates its own set of security problems.
>>>>>>
>>>>>> *Item No 3*: Forcing AS to implement OIDC specifications will render
>>>>>> existing implementations non-compliant.
>>>>>> *Follow-up Comments-v2*.
>>>>>>
>>>>>>> I don't see how this as being biased. I see it as a pragmatic
>>>>>>> decision aimed at simplification and interoperability.
>>>>>>
>>>>>> Using two simple constructs may seem innocuous at first, but it does
>>>>>> give an impression that OIDC is the preferred mechanism for the
>>>>>> authentication of the end-user as compared to any other implementations.
>>>>>>
>>>>>> *Item No 4*: How much “Freshness” is fresh?
>>>>>> *Follow-up Comments-v2*. The parameters like "expires_in" have
>>>>>> already been defined in the original RFC 6749 without the need of the term
>>>>>> "Freshness".
>>>>>>
>>>>>> *Item No 5*: Why not include client app parameters in the signal
>>>>>> flow?
>>>>>> *Comments*. Vittorio's answer to Yusuf's email dated 13 Oct 2022.
>>>>>>
>>>>>>> During the discussion we did inquire on other parameters/aspects
>>>>>>> that would have the same direct applicability but nothing was identified.
>>>>>>
>>>>>> We may consider including various parameters of the client app in the
>>>>>> step-up as it is intrinsic to the OAuth 2.0 specs and plays a big role in
>>>>>> how the permission is granted for restricted scopes.
>>>>>>
>>>>>> Let us see how Google handles the restricted scopes. Refer here
>>>>>> <https://developers.google.com/identity/protocols/oauth2/production-readiness/restricted-scope-verification>
>>>>>> .
>>>>>>
>>>>>>> The Gmail and Fit APIs limit the apps that can seek permission to
>>>>>>> access consumer data. These additional requirements for restricted scopes
>>>>>>> require an app to demonstrate that they're a permitted application type and
>>>>>>> to submit to additional reviews, which include a possible security
>>>>>>> assessment by a third-party auditor.
>>>>>>
>>>>>> Here, the problem of restricted or sensitive scopes is handled
>>>>>> through security assessment of the apps requesting these scopes.
>>>>>>
>>>>>> The signal related to the client app could therefore carry the
>>>>>> following information:
>>>>>> a. Type of client app
>>>>>> b. How has it been identified i.e using basic authentication, mTLS or
>>>>>> other such techniques.
>>>>>> c. Security assessment of the client app
>>>>>>
>>>>>> Wishing everyone a Happy Diwali
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Sat, Oct 22, 2022 at 12:49 AM Brian Campbell <bcampbell=
>>>>>> [e-mail]> wrote:
>>>>>>
>>>>>>> Thanks Warren, it's a good reminder about REQUIRED/MUST/etc meaning
>>>>>>> in the context of the given document.
>>>>>>>
>>>>>>> As far as references are concerned. IETF documents can reference
>>>>>>> non-IETF documents. It's not at all uncommon. And a number of OAuth RFCs
>>>>>>> and in-progress drafts do already reference OIDC; draft-ietf-oauth-v2-1,
>>>>>>> draft-ietf-oauth-security-topics, rfc9068, rfc8725, rfc9101, rfc9126,
>>>>>>> rfc9207 being just a partial list.
>>>>>>>
>>>>>>>
>>>>>>> On Fri, Oct 21, 2022 at 6:39 AM Warren Parad <wparad=
>>>>>>> [e-mail]> wrote:
>>>>>>>
>>>>>>>> REQUIRED always means "in the context of the RFC".
>>>>>>>>
>>>>>>>> I fully agree to your statement that 'existing implementations
>>>>>>>>> aren't expected to comply with the new specification'. However, the point I
>>>>>>>>> am making is that we cannot be biased towards OIDC specifications and leave
>>>>>>>>> others non-compliant. We have to make future specifications such that it
>>>>>>>>> doesn't favour one over other.
>>>>>>>>
>>>>>>>>
>>>>>>>> Regarding OAuth 2.0 references, we already have a AS metadata
>>>>>>>> parameter and the AS doesn't have to return the acr values, which in itself
>>>>>>>> is a signal. So switching the expectations to OPTIONAL, in my opinion would
>>>>>>>> be a mistake. We aren't leaving others as "non-compliant". Sure they are
>>>>>>>> "non-compliant" with this new RFC, but they aren't "non-compliant" with
>>>>>>>> regards to OIDC nor OAuth2.0.
>>>>>>>>
>>>>>>>> On the flip side, I'm not sure how I feel about directly
>>>>>>>> referencing the implementations found in OIDC. If there is a pattern we
>>>>>>>> wish to adapt, it does follow for me that we explicitly document that
>>>>>>>> pattern within the RFC and not link to the OIDC reference.
>>>>>>>>
>>>>>>>>
>>>>>>>> On Fri, Oct 21, 2022 at 2:04 PM Jaimandeep Singh
>>>>>>>> <jaimandeep.phdcs21=[e-mail]> wrote:
>>>>>>>>
>>>>>>>>> Dear Vittorio,
>>>>>>>>>
>>>>>>>>> Thankyou for the detailed reply. My follow-on suggestions and
>>>>>>>>> recommendations are given below for kind consideration please [The original
>>>>>>>>> suggestions can be found here
>>>>>>>>> <https://mailarchive.ietf.org/arch/msg/oauth/rNqEACxVM1OtDfT5SIQDybSK6kk/>
>>>>>>>>> ]:
>>>>>>>>>
>>>>>>>>> *Item No 1*: Striking at the core of OAuth 2.0 idea by coupling
>>>>>>>>> end user authentication with authorization.
>>>>>>>>> *Follow-on Comment*: Thx for bringing out that RFC 9068 already
>>>>>>>>> has "acr'' as a claim. However, it is an OPTIONAL claim, whereas section 5
>>>>>>>>> of the draft RFC recommends it to be a required parameter. Notwithstanding,
>>>>>>>>> in my view, the proposed draft is challenging the very premises of OAuth
>>>>>>>>> 2.0 by strongly coupling the authorization layer with the end user
>>>>>>>>> authentication. The OAuth 2.0 is supposed to be agnostic to the end user
>>>>>>>>> authentication. Are we comfortable with this coupling?
>>>>>>>>> *Recommendation*: The draft RFC should be made informational. If
>>>>>>>>> that is out of scope then all the proposed claims, parameters and headers
>>>>>>>>> should be made OPTIONAL.
>>>>>>>>>
>>>>>>>>> *Item No 2*: Punching a security hole by requiring AS to act on
>>>>>>>>> information provided by the client applications (Reverse Flow).
>>>>>>>>> *Follow-on Comment*: I would like to differ on this view. The
>>>>>>>>> client applications do require authentication in case of confidential
>>>>>>>>> clients (Refer Section 2.3 of RFC 6749). I would also like to point towards
>>>>>>>>> the Google OAuth 2.0 page which talks about 'creation of authorization
>>>>>>>>> credentials' by the client applications and can be accessed here
>>>>>>>>> <https://developers.google.com/identity/protocols/oauth2/web-server>
>>>>>>>>> .
>>>>>>>>>    The point I am making is that the client application needs to
>>>>>>>>> authenticate itself with the OAuth 2.0 endpoint before starting the
>>>>>>>>> communication. Also, making AS act on information provided by
>>>>>>>>> client applications may lead to future vulnerabilities as client
>>>>>>>>> applications are not considered 'trusted' especially when we follow zero
>>>>>>>>> trust architecture.
>>>>>>>>> *Recommendation*.
>>>>>>>>>
>>>>>>>>> a. The example given in section 4 of draft RFC be updated to
>>>>>>>>> reflect the need of complete authentication of the client application
>>>>>>>>> before the "acr_values" or "max_age" values are accepted or acted upon by
>>>>>>>>> the OAuth 2.0 endpoint.
>>>>>>>>> b. Need for signing these values by the RS which can be verified
>>>>>>>>> by the AS. Therefore, we need to look at ways by which the RS returns a
>>>>>>>>> signed JWT token containing "acr_values" or other such claims which should
>>>>>>>>> also be opaque to the client applications.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> *Item No 3*: Forcing AS to implement OIDC specifications will
>>>>>>>>> render existing implementations non-compliant.
>>>>>>>>> *Follow-on Comment*: I fully agree to your statement that
>>>>>>>>> 'existing implementations aren't expected to comply with the new
>>>>>>>>> specification'. However, the point I am making is that we cannot be biased
>>>>>>>>> towards OIDC specifications and leave others non-compliant. We have to make
>>>>>>>>> future specifications such that it doesn't favour one over other.
>>>>>>>>> *Recommendations*: All the proposed claims, parameters and
>>>>>>>>> headers should be made OPTIONAL.
>>>>>>>>>
>>>>>>>>> *Item No 4*: How much “Freshness” is fresh?
>>>>>>>>> *Follow-on Comment*: The *term* "freshness" may have earlier
>>>>>>>>> precedent but the context is different.
>>>>>>>>> *Recommendation*. Let's not use a term which cannot be quantified
>>>>>>>>> and is open to different interpretations by readers/implementers.
>>>>>>>>>
>>>>>>>>> Kind Regards
>>>>>>>>> Jaimandeep Singh
>>>>>>>>>
>>>>>>>>> On Fri, Oct 21, 2022 at 2:53 AM Vittorio Bertocci <vittorio=
>>>>>>>>> [e-mail]> wrote:
>>>>>>>>>
>>>>>>>>>> Hi Jaimandeep,
>>>>>>>>>> I have a bit of cognitive whiplash - your first message professed
>>>>>>>>>> strong support for this work, further reinforced by a LinkedIn post where
>>>>>>>>>> you mentioned that your own paper supports the ideas expressed in this spec
>>>>>>>>>> (not linking it because it's gone, but I have a screenshot)- whereas in
>>>>>>>>>> your latest message you raise objections that question the very
>>>>>>>>>> existence of this document... anyway, to your comments:
>>>>>>>>>>
>>>>>>>>>> 1 - I don't understand what "striking at the very core of OAuth"
>>>>>>>>>> really means in concrete terms, however passing ACR in an access token is
>>>>>>>>>> already standard behavior as described in
>>>>>>>>>> https://datatracker.ietf.org/doc/html/rfc9068, as referenced by
>>>>>>>>>> the draft.
>>>>>>>>>> For what concerns the clientID considerations - the draft is
>>>>>>>>>> pretty clear on aiming to solve scenarios where the RS is the entity
>>>>>>>>>> deciding to reject incoming tokens for its own reasons, such as risk
>>>>>>>>>> assessment performed locally, that by definition cannot be determined
>>>>>>>>>> solely on the basis of the client identity.
>>>>>>>>>>
>>>>>>>>>> 2 - I have a hard time parsing this objection as well. A client
>>>>>>>>>> does NOT authenticate itself when hitting the authorization endpoint,
>>>>>>>>>> regardless of the client flavor;  whether the oauth spec accepts a
>>>>>>>>>> parameter or not isn't really relevant in an spec whose intent is to
>>>>>>>>>> _extend_ oauth; and saying that the client is untrusted doesn't mean that
>>>>>>>>>> the AS wouldn't comply with request parameters, because once again the
>>>>>>>>>> authorization endpoint doesn't require ANy client authentication.
>>>>>>>>>>
>>>>>>>>>> 3- New RFCs don't override existing specs: they build on existing
>>>>>>>>>> specs by extending and/or constraining existing behaviors. Forward
>>>>>>>>>> compatibility would require the ability to predict the future, hence
>>>>>>>>>> existing implementations aren't expected to comply with the new
>>>>>>>>>> specification until they decide to add support for it. Now for this
>>>>>>>>>> particular specification, we might get lucky and have forward compatibility
>>>>>>>>>> in many implementations as products often implement both OAuth and OIDC in
>>>>>>>>>> the same codebase, but once again - that is definitely not required.
>>>>>>>>>>
>>>>>>>>>> 4- Also in this case, I am not sure how to read this objection.
>>>>>>>>>> The use of the *term* "freshness" has precedent in IETF specs (see rfc8747)
>>>>>>>>>> and is commonly used in discussions on the list; and the concept is very
>>>>>>>>>> well known and understood, as the existence of the max_age parameter
>>>>>>>>>> attests; the fact that it is defined in OIDC doesn't really matter in this
>>>>>>>>>> context, it is common practice for RS to impose the same constraint- one of
>>>>>>>>>> the reasons that prompted us to draft this extension.
>>>>>>>>>>
>>>>>>>>>> I hope this helps!
>>>>>>>>>> Best,
>>>>>>>>>> V.
>>>>>>>>>>
>>>>>>>>>> On Thu, Oct 20, 2022 at 10:10 AM Jaimandeep Singh
>>>>>>>>>> <jaimandeep.phdcs21=[e-mail]> wrote:
>>>>>>>>>>
>>>>>>>>>>> *This message originated outside your organization.*
>>>>>>>>>>>
>>>>>>>>>>> ------------------------------
>>>>>>>>>>>
>>>>>>>>>>> Dear Vittorio Bertocci, Brian Campbell and Rifaat,
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> My sincere compliments to Vittorio and Brian for their
>>>>>>>>>>> persistent efforts in making and improving the draft RFC and also for
>>>>>>>>>>> taking out valuable time and efforts to reply to any queries. However, I
>>>>>>>>>>> strongly feel that the following points should be addressed before closing
>>>>>>>>>>> the last call.
>>>>>>>>>>>
>>>>>>>>>>> Item No 1: Striking at the core of OAuth 2.0 idea by coupling
>>>>>>>>>>> end user authentication with authorization.
>>>>>>>>>>>
>>>>>>>>>>> Explanation: OAuth 2.0 is an authorization protocol. Its
>>>>>>>>>>> strength lies in the decoupling of the end user authentication with the
>>>>>>>>>>> authorization layer. The proposed draft proposes means of coupling the two
>>>>>>>>>>> by passage of authentication information down the complete OAuth 2.0 chain
>>>>>>>>>>> and then RECOMMENDS actions by AS based on this information, thereby
>>>>>>>>>>> striking at the core idea of OAuth 2.0.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> The idea of end user authentication information being
>>>>>>>>>>> transferred to the AS is borrowed from OIDC, which sends this information
>>>>>>>>>>> through token ID in the form of JWT (Refer Section 2 of OIDC specs). This
>>>>>>>>>>> parameter is designed to be OPTIONAL in OIDC and is not further passed in
>>>>>>>>>>> the access tokens. In the draft RFC we are not only passing the
>>>>>>>>>>> authentication information down the chain through access tokens but also
>>>>>>>>>>> acting on the information received from client applications upstream.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> The idea of fiddling with end user authentication is completely
>>>>>>>>>>> foreign to the OAuth 2.0 specs. Following questions then arise:
>>>>>>>>>>>
>>>>>>>>>>>    1.
>>>>>>>>>>>
>>>>>>>>>>>    Do we intend to extend the scope of OAuth 2.0 specs by
>>>>>>>>>>>    coupling it with the end-user authentication and striking at the very core
>>>>>>>>>>>    idea of OAuth 2.0?
>>>>>>>>>>>    2.
>>>>>>>>>>>
>>>>>>>>>>>    OAuth 2.0 does require means of identification for the
>>>>>>>>>>>    client application either through client ID only in case of public clients
>>>>>>>>>>>    or through basic authentication in case of confidential clients. Is it not
>>>>>>>>>>>    better to look at step-up identification/authentication requirements of the
>>>>>>>>>>>    client application i.e. the way the client application
>>>>>>>>>>>    identifies/authenticates itself with the AS instead of getting involved
>>>>>>>>>>>    with the mechanics of end user authentication. The idea of client
>>>>>>>>>>>    application authentication is intrinsic to the OAuth 2.0 specs.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Item No 2: Punching a security hole by requiring AS to act on
>>>>>>>>>>> information provided by the client applications (Reverse Flow).
>>>>>>>>>>>
>>>>>>>>>>> Explanation. Refer Section 4 of draft RFC
>>>>>>>>>>>
>>>>>>>>>>> The example request below, which might occur after receiving the
>>>>>>>>>>>> challenge in Figure 2, indicates to the authorization server that the
>>>>>>>>>>>> client would like the authentication to occur according to the
>>>>>>>>>>>> authentication context class reference identified by myACR.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>> GET https://as.example.net/authorize?client_id=s6BhdRkqt3
>>>>>>>>>>>> <https://urldefense.com/v3/__https://as.example.net/authorize?client_id=s6BhdRkqt3__;!!PwKahg!7gVZGCGaFSdlozdZ1AdZhFCyfxK8nxToBplJ45oqxst0UKwrmcGMaeEYQpCbT54MpXqFjVoQflkoFpwtN5sadjP3seHNQRw$>
>>>>>>>>>>>> &response_type=code&scope=purchase&acr_values=myACR
>>>>>>>>>>>> Figure 4: Authorization Request indicating acr_values
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> In OAuth 2.0 specs, the client application authenticates itself
>>>>>>>>>>> with the AS before starting the flow. Here, in the example above there are
>>>>>>>>>>> two prominent flaws:
>>>>>>>>>>>
>>>>>>>>>>>    1.
>>>>>>>>>>>
>>>>>>>>>>>    The unauthenticated rogue client makes a GET request to the
>>>>>>>>>>>    AS forcing the complete authentication breakdown at the end user forcing
>>>>>>>>>>>    him to authenticate time over and again.
>>>>>>>>>>>    2.
>>>>>>>>>>>
>>>>>>>>>>>    Even if we take a scenario that the request is made by an
>>>>>>>>>>>    authenticated client, the original specs of OAuth 2.0 does not mandate any
>>>>>>>>>>>    action based on the commands received from the client application. In a
>>>>>>>>>>>    zero trust model we assume that the client is compromised. AS acting on
>>>>>>>>>>>    commands of client applications and propagating them across the ecosystem
>>>>>>>>>>>    to force the end user authentication may result in future unseen
>>>>>>>>>>>    vulnerabilities.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Item No 3: Forcing AS to implement OIDC specifications will
>>>>>>>>>>> render existing implementations non-compliant.
>>>>>>>>>>>
>>>>>>>>>>> Explanation. Refer Section 5 of the draft specs.
>>>>>>>>>>>
>>>>>>>>>>> Although [OIDC] leaves the authorization server free to decide
>>>>>>>>>>>> how to handle the inclusion of acr in ID Token when requested via
>>>>>>>>>>>> acr_values, when it comes to access tokens in this specification it is
>>>>>>>>>>>> RECOMMENDED that the requested acr value is treated as required for
>>>>>>>>>>>> successfully fulfilling the request.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> The *RECOMMENDED *and *required* “acr_values” in the access
>>>>>>>>>>> tokens will render existing deployments of AS, which currently do not
>>>>>>>>>>> support OIDC, as non-compliant.
>>>>>>>>>>>
>>>>>>>>>>> Item No 4: How much “Freshness” is fresh?
>>>>>>>>>>>
>>>>>>>>>>> Explanation. The use of the word “Freshness” is not quantified
>>>>>>>>>>> and does not convey any meaning. It is recommended to be removed
>>>>>>>>>>> altogether. On the contrary it complicates the draft, making the reader
>>>>>>>>>>> assume that “freshness” of authentication is very important and might
>>>>>>>>>>> impact on the whole idea of access tokens and the OAuth 2.0 in the first
>>>>>>>>>>> place.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Tue, Oct 18, 2022 at 1:25 AM Brian Campbell <bcampbell=
>>>>>>>>>>> [e-mail]> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Thanks Jaimandeep,
>>>>>>>>>>>>
>>>>>>>>>>>> There are certainly some complementary aspects of the step-up
>>>>>>>>>>>> work and adaptive risk based approaches. Both in conveying information
>>>>>>>>>>>> in/with an access token that might be input into a risk score calculation
>>>>>>>>>>>> and in signaling that a more recent and/or stronger user authentication
>>>>>>>>>>>> is required when the calculated risk exceeds the allowed risk.
>>>>>>>>>>>>
>>>>>>>>>>>> On Sat, Oct 15, 2022 at 10:58 PM Jaimandeep Singh
>>>>>>>>>>>> <jaimandeep.phdcs21=[e-mail]> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Dear Brian,
>>>>>>>>>>>>>
>>>>>>>>>>>>> I strongly support this work. I have recently written a
>>>>>>>>>>>>> conference paper on supporting similar ideas titled '*Resilient
>>>>>>>>>>>>> Risk based Adaptive Authentication and Authorization (RAD-AA) Framework*'.
>>>>>>>>>>>>> The paper is still in the pre-print stage and can be accessed
>>>>>>>>>>>>> here
>>>>>>>>>>>>> <https://urldefense.com/v3/__https://arxiv.org/abs/2208.02592__;!!PwKahg!7gVZGCGaFSdlozdZ1AdZhFCyfxK8nxToBplJ45oqxst0UKwrmcGMaeEYQpCbT54MpXqFjVoQflkoFpwtN5sadjP3zA283j8$>.
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> 1. The core idea is similar. Firstly, ability to revoke or
>>>>>>>>>>>>> step-up the authentication requirements based on the risk score. Secondly,
>>>>>>>>>>>>> to limit the scope based on the risk score.
>>>>>>>>>>>>>
>>>>>>>>>>>>> 2. One of the factors determining the risk score is the way
>>>>>>>>>>>>> the client application has authenticated with the Authorization server. If
>>>>>>>>>>>>> it has used basic auth the risk score is high as compared to mTLS.
>>>>>>>>>>>>>
>>>>>>>>>>>>> 3. Additionally the idea is to downgrade the scope of the
>>>>>>>>>>>>> token in case the risk score is high. This could be achieved at the
>>>>>>>>>>>>> protected resource server end through introspection and at authorization
>>>>>>>>>>>>> server end while issuing new access when the older ones expire. This can
>>>>>>>>>>>>> avoid forcing the complete authentication cycle at client end.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Regards
>>>>>>>>>>>>> Jaimandeep Singh
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Wed, Oct 12, 2022 at 3:25 AM Brian Campbell <bcampbell=
>>>>>>>>>>>>> [e-mail]> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> I don't know offhand a better place or if your specific
>>>>>>>>>>>>>> privacy consideration is already covered. Honestly, with that comment, I
>>>>>>>>>>>>>> was just aiming to keep the scope of this document concise and relevant.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On Tue, Oct 11, 2022 at 10:06 AM Denis <[e-mail]>
>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Hi Brian,
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I agree with you that "must not" is more appropriate in that
>>>>>>>>>>>>>>> context.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I also agree with you that the "privacy implications of
>>>>>>>>>>>>>>> opaque tokens are inherent to OAuth in general".
>>>>>>>>>>>>>>> However, I have not reviewed all the RFCs and I wonder
>>>>>>>>>>>>>>> whether such a privacy consideration has already been mentioned.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> It would be nice to start to mention it, rather than to
>>>>>>>>>>>>>>> continue to omit it. Do you see a better place to mention it ?
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Denis
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Thanks Denis, I agree the word "cannot" isn't quite right
>>>>>>>>>>>>>>> there. I struggled with trying to find the right wording (more than I
>>>>>>>>>>>>>>> probably should have) attempting to add a note/reminder without getting
>>>>>>>>>>>>>>> into normative sounding language. But I also wanted to make a firm
>>>>>>>>>>>>>>> statement. Words are hard sometimes. Oftentimes! But reading it again
>>>>>>>>>>>>>>> today, "cannot" doesn't work very well. I think changing to "must not" is
>>>>>>>>>>>>>>> appropriate. The privacy implications of opaque tokens are inherent to
>>>>>>>>>>>>>>> OAuth in general and I don't believe this draft is an appropriate place to
>>>>>>>>>>>>>>> attempt to give them treatment.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On Tue, Oct 11, 2022 at 2:57 AM Denis <[e-mail]>
>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Hi Brian,
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> The text states:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Also recall that OAuth 2.0 [RFC6749] assumes access tokens
>>>>>>>>>>>>>>>> are treated as
>>>>>>>>>>>>>>>> opaque by clients. So, during the course of any token
>>>>>>>>>>>>>>>> caching
>>>>>>>>>>>>>>>> strategy, a client *cannot* inspect the content of the
>>>>>>>>>>>>>>>> access token to
>>>>>>>>>>>>>>>> determine the associated authentication information or
>>>>>>>>>>>>>>>> other details.
>>>>>>>>>>>>>>>> The token format might be unreadable to the client or might
>>>>>>>>>>>>>>>> change at
>>>>>>>>>>>>>>>> any time to become unreadable.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> A client *can *inspect the content of the access token.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> A better wording  would be:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> ...  a client *should not *inspect the content of the
>>>>>>>>>>>>>>>> access token ...
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> It would be worthwhile to add a Privacy Considerations
>>>>>>>>>>>>>>>> section:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> 10. Privacy Considerations
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Since access tokens are presumed to be opaque to clients,
>>>>>>>>>>>>>>>> clients (and hence users) are not supposed to inspect the content of the
>>>>>>>>>>>>>>>> access tokens.
>>>>>>>>>>>>>>>> Authorizations Servers are able to disclose more
>>>>>>>>>>>>>>>> information than strictly necessary about the authenticated user without
>>>>>>>>>>>>>>>> the end user being
>>>>>>>>>>>>>>>> able to know it. Such additional information may endanger
>>>>>>>>>>>>>>>> the privacy of the user.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Denis
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I've published an -04. It has that very minor change. There
>>>>>>>>>>>>>>>> was also an off-list discussion during WGLC that resulted in thinking it'd
>>>>>>>>>>>>>>>> be worthwhile
>>>>>>>>>>>>>>>> *to add a reminder that access tokens are opaque to clients*.
>>>>>>>>>>>>>>>> So I took that as LC feedback and -04 adds a brief note towards that end.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> https://datatracker.ietf.org/doc/draft-ietf-oauth-step-up-authn-challenge/
>>>>>>>>>>>>>>>> <https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-ietf-oauth-step-up-authn-challenge/__;!!PwKahg!7gVZGCGaFSdlozdZ1AdZhFCyfxK8nxToBplJ45oqxst0UKwrmcGMaeEYQpCbT54MpXqFjVoQflkoFpwtN5sadjP3CV1UVi4$>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> On Mon, Oct 10, 2022 at 1:22 PM Vittorio Bertocci <vittorio=
>>>>>>>>>>>>>>>> [e-mail]> wrote:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Thanks Dima for the comment. Some thoughts:
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> > (editorial)...
>>>>>>>>>>>>>>>>> Good point. "statically" would characterize the simplest
>>>>>>>>>>>>>>>>> of the scenarios, but in fact any case where the AS is the only arbiter of
>>>>>>>>>>>>>>>>> the authn level works for the point we are trying to make. We'll drop
>>>>>>>>>>>>>>>>> "statically". Thanks!
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> > Apart from...
>>>>>>>>>>>>>>>>> This spec focuses on empowering an RS to communicate its
>>>>>>>>>>>>>>>>> ACR and freshness requirements, regardless of the reasons leading the RS to
>>>>>>>>>>>>>>>>> make that determination: the logic by which that happens is explicitly out
>>>>>>>>>>>>>>>>> of scope, and in many real life cases it might simply be unknowable (eg
>>>>>>>>>>>>>>>>> anomaly detection engines based on ML are often back boxes). The mechanism
>>>>>>>>>>>>>>>>> described here can be used alongside other mechanisms that might require
>>>>>>>>>>>>>>>>> the client to get the user to interact with the AS, as it is the case for
>>>>>>>>>>>>>>>>> insufficient_scope, but those remain distinct cases (eg insufficient _scope
>>>>>>>>>>>>>>>>> might not require any step up but simply explicit user consent, and if it
>>>>>>>>>>>>>>>>> does require a stepup, that's entirely determined by the AS without any
>>>>>>>>>>>>>>>>> communication with client or RS required).
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> On Fri, Oct 7, 2022 at 17:43 Dima Postnikov <
>>>>>>>>>>>>>>>>> [e-mail]> wrote:
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> *This message originated outside your organization.*
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> ------------------------------
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Couple of quick comments from me:
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> 1) (Editorial) >In simple API authorization scenarios, an
>>>>>>>>>>>>>>>>>> authorization server will statically determine what authentication technique
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> In many scenarios, authorization servers will use
>>>>>>>>>>>>>>>>>> *dynamic* decisioning to determine authentication
>>>>>>>>>>>>>>>>>> techniques; it's just not exposed to the client in a way
>>>>>>>>>>>>>>>>>> to make it actionable (which is why this specification's intent makes
>>>>>>>>>>>>>>>>>> perfect sense).
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> 2) Apart from authentication level, there might be other
>>>>>>>>>>>>>>>>>> reasons why users might be forced to go through the authorization flow, for
>>>>>>>>>>>>>>>>>> example, insufficient authorization / scopes / claims / etc.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> If there is a mechanism to let the client know, as a
>>>>>>>>>>>>>>>>>> practitioner, i'd rather have the same approach for both authentication and
>>>>>>>>>>>>>>>>>> authorization. There are a range of authorization policy engines in the
>>>>>>>>>>>>>>>>>> market that could return "STEP UP is required" after looking at
>>>>>>>>>>>>>>>>>> authentication, authorisation and many other real-time signals. It's just
>>>>>>>>>>>>>>>>>> not standardized...
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> On Sat, Oct 8, 2022 at 7:30 AM Pieter Kasselman
>>>>>>>>>>>>>>>>>> <pieter.kasselman=[e-mail]> wrote:
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> I am very supportive of this work and have been working
>>>>>>>>>>>>>>>>>>> through different use cases to see whether it can satisfy the requirements
>>>>>>>>>>>>>>>>>>> that arise from them.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> One observation from working through these uses cases is
>>>>>>>>>>>>>>>>>>> that as customers move to Zero Trust architectures, we are seeing customers
>>>>>>>>>>>>>>>>>>> adopting finer grained policy segmentation. Consequently customers are
>>>>>>>>>>>>>>>>>>> planning to deploy segmented access control by data or action sensitivity,
>>>>>>>>>>>>>>>>>>> within a service. This approach to policy design makes it more common for a
>>>>>>>>>>>>>>>>>>> single service to depend on multiple authentication context values or
>>>>>>>>>>>>>>>>>>> combinations of authentication context values.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> An example of this is a policy that has multiple acr
>>>>>>>>>>>>>>>>>>> values (e.g. acr1=password, acr2=FIDO, acr3=selfie check, acr4=trusted
>>>>>>>>>>>>>>>>>>> network). A customer may define a policy that requires different
>>>>>>>>>>>>>>>>>>> combinations of these acr values, for example, a file server may requires
>>>>>>>>>>>>>>>>>>> password for general access (e.g. acr1), FIDO authentication (acr2) or
>>>>>>>>>>>>>>>>>>> password access and being on a trusted network to read sensitive data (acr
>>>>>>>>>>>>>>>>>>> 2 of (acr1 + acr 4), FIDO authentication and password (acr1 + acr2) for
>>>>>>>>>>>>>>>>>>> accessing editing sensitive documents and a real-time selfie check on top
>>>>>>>>>>>>>>>>>>> of FIDO and presence on a trusted network  (acr1 + acr2 + acr3 + acr4) to
>>>>>>>>>>>>>>>>>>> initiate a sensitive workflow (e.g. check-in code). Other variations of
>>>>>>>>>>>>>>>>>>> this includes database access with different types of access requirement
>>>>>>>>>>>>>>>>>>> for certain rows (row-level permissions) or columns (column level
>>>>>>>>>>>>>>>>>>> permissions) with different combinations of acr values.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> I was curious if this type of scenario where multiple
>>>>>>>>>>>>>>>>>>> authentication contexts and combinations of contexts are required is
>>>>>>>>>>>>>>>>>>> something others see (or are beginning to see) as well?
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Cheers
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Pieter
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> *From:* OAuth <[e-mail]> *On Behalf Of *Rifaat
>>>>>>>>>>>>>>>>>>> Shekh-Yusef
>>>>>>>>>>>>>>>>>>> *Sent:* Thursday, September 22, 2022 3:02 PM
>>>>>>>>>>>>>>>>>>> *To:* oauth <[e-mail]>
>>>>>>>>>>>>>>>>>>> *Subject:* Re: [OAUTH-WG] WGLC for Step-up
>>>>>>>>>>>>>>>>>>> Authentication
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> *Correction:*
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Please, review the document and provide your feedback on
>>>>>>>>>>>>>>>>>>> the mailing list by *Oct 7th, 2022*.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> On Thu, Sep 22, 2022 at 9:52 AM Rifaat Shekh-Yusef <
>>>>>>>>>>>>>>>>>>> [e-mail]> wrote:
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> All,
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> This is to start a *WG Last Call *for the *Step-up
>>>>>>>>>>>>>>>>>>> Authentication *document:
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> https://www.ietf.org/archive/id/draft-ietf-oauth-step-up-authn-challenge-03.html
>>>>>>>>>>>>>>>>>>> <https://urldefense.com/v3/__https://nam06.safelinks.protection.outlook.com/?url=https*3A*2F*2Fwww.ietf.org*2Farchive*2Fid*2Fdraft-ietf-oauth-step-up-authn-challenge-03.html&data=05*7C01*7Cpieter.kasselman*40microsoft.com*7C0078f809101147bc978308da9ca32020*7C72f988bf86f141af91ab2d7cd011db47*7C1*7C0*7C637994521713812011*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C3000*7C*7C*7C&sdata=18sfemyWqYb06PvUA9eTLaq0ccDY14*2F6ETo58JpE*2FJQ*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSUl!!PwKahg!537tJQfGj3Z_Yi2waywl1VPGyDs9818JE-M-KNFgPtoB0O26a7ksRvAYrPyzfKKXsMKCVblAomtRXj8$>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Please, review the document and provide your feedback on
>>>>>>>>>>>>>>>>>>> the mailing list by *Sep 30th, 2022*.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Regards,
>>>>>>>>>>>>>>>>>>>  Rifaat & Hannes
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>>>>>>> OAuth mailing list
>>>>>>>>>>>>>>>>>>> [e-mail]
>>>>>>>>>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/oauth
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>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>>>>>> OAuth mailing list
>>>>>>>>>>>>>>>>>> [e-mail]
>>>>>>>>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/oauth
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>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>>>>> OAuth mailing list
>>>>>>>>>>>>>>>>> [e-mail]
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>>>>>>>>>>>>>>>>> <https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/oauth__;!!PwKahg!7gVZGCGaFSdlozdZ1AdZhFCyfxK8nxToBplJ45oqxst0UKwrmcGMaeEYQpCbT54MpXqFjVoQflkoFpwtN5sadjP3O4Vq9Uo$>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> *CONFIDENTIALITY NOTICE: This email may contain
>>>>>>>>>>>>>>>> confidential and privileged material for the sole use of the intended
>>>>>>>>>>>>>>>> recipient(s). Any review, use, distribution or disclosure by others is
>>>>>>>>>>>>>>>> strictly prohibited.  If you have received this communication in error,
>>>>>>>>>>>>>>>> please notify the sender immediately by e-mail and delete the message and
>>>>>>>>>>>>>>>> any file attachments from your computer. Thank you.*
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>>>> OAuth mailing [e-mail]://www.ietf.org/mailman/listinfo/oauth <https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/oauth__;!!PwKahg!7gVZGCGaFSdlozdZ1AdZhFCyfxK8nxToBplJ45oqxst0UKwrmcGMaeEYQpCbT54MpXqFjVoQflkoFpwtN5sadjP3O4Vq9Uo$>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> *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.*
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>> *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.*
>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>> OAuth mailing list
>>>>>>>>>>>>>> [e-mail]
>>>>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/oauth
>>>>>>>>>>>>>> <https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/oauth__;!!PwKahg!7gVZGCGaFSdlozdZ1AdZhFCyfxK8nxToBplJ45oqxst0UKwrmcGMaeEYQpCbT54MpXqFjVoQflkoFpwtN5sadjP3O4Vq9Uo$>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> --
>>>>>>>>>>>>> Regards and Best Wishes
>>>>>>>>>>>>> Jaimandeep Singh
>>>>>>>>>>>>> LinkedIn
>>>>>>>>>>>>> <http://www.linkedin.com/in/jaimandeep-singh-07834b1b7>
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> *CONFIDENTIALITY NOTICE: This email may contain confidential
>>>>>>>>>>>> and privileged material for the sole use of the intended recipient(s). Any
>>>>>>>>>>>> review, use, distribution or disclosure by others is strictly prohibited.
>>>>>>>>>>>> If you have received this communication in error, please notify the sender
>>>>>>>>>>>> immediately by e-mail and delete the message and any file attachments from
>>>>>>>>>>>> your computer. Thank you.*
>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>> OAuth mailing list
>>>>>>>>>>>> [e-mail]
>>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/oauth
>>>>>>>>>>>> <https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/oauth__;!!PwKahg!7gVZGCGaFSdlozdZ1AdZhFCyfxK8nxToBplJ45oqxst0UKwrmcGMaeEYQpCbT54MpXqFjVoQflkoFpwtN5sadjP3O4Vq9Uo$>
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> Regards and Best Wishes
>>>>>>>>>>> Jaimandeep Singh
>>>>>>>>>>> LinkedIn <http://www.linkedin.com/in/jaimandeep-singh-07834b1b7>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> OAuth mailing list
>>>>>>>>>>> [e-mail]
>>>>>>>>>>> https://www.ietf.org/mailman/listinfo/oauth
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Regards and Best Wishes
>>>>>>>>> Jaimandeep Singh
>>>>>>>>> LinkedIn <http://www.linkedin.com/in/jaimandeep-singh-07834b1b7>
>>>>>>>>> _______________________________________________
>>>>>>>>> OAuth mailing list
>>>>>>>>> [e-mail]
>>>>>>>>> https://www.ietf.org/mailman/listinfo/oauth
>>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> OAuth mailing list
>>>>>>>> [e-mail]
>>>>>>>> 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). 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.*
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Regards and Best Wishes
>>>>>> Jaimandeep Singh
>>>>>> LinkedIn <http://www.linkedin.com/in/jaimandeep-singh-07834b1b7>
>>>>>>
>>>>>
>>>>
>>>> --
>>>> Regards and Best Wishes
>>>> Jaimandeep Singh
>>>> LinkedIn <http://www.linkedin.com/in/jaimandeep-singh-07834b1b7>
>>>>
>>>
>>>
>>> --
>>> Regards and Best Wishes
>>> Jaimandeep Singh
>>> LinkedIn <http://www.linkedin.com/in/jaimandeep-singh-07834b1b7>
>>>
>>
>
> --
> Regards and Best Wishes
> Jaimandeep Singh
> LinkedIn <http://www.linkedin.com/in/jaimandeep-singh-07834b1b7>
> _______________________________________________
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