[keycloak-dev] Override Refresh token lifespan per client

[Stian Thorgersen]

Thanks for your comments and yes they make sense. I think we mostly have
the same opinion here.

What is achievable with Keycloak today puts a fair bit of the effort on the
application and the RP. Firstly the RP/API would need to be able to find
out how long since the user authenticated, which it can as that can be
added as a claim to the token. The RP can then reject request if it's to
long since the user authenticated. Further, the application (web/UI) would
need to use max_age and/or prompt=login to force the user to
re-authenticate.

Taking this one step further to step-up authentication which we plan to
introduce in the not to distant future. In this case the application can
use acr_values to request step-up. This also needs to most likely be
validated by the RP, which somehow needs to communicate this to the
applications.

Ideally Keycloak would have some support to make this easier and not have
to put all the burden on the app and the RP, but AFAIK there's no real
standard way of doing that. One idea is that we could somehow drive it
through client scopes. Let's say you have a client scope named
"high-risk-scope". Setting a max_age and also an acr value on the client
scope itself within Keycloak means that everytime an application requests a
token with that scope the refresh token timeout would be set accordingly
and the user would be required to authenticate at the appropriate level.

In summary though - this is something that needs to be thought through
properly. Right now I have too many things on my plate to start working on
any sort of design proposal around this, but if anyone from the community
would like to start working on something that would be great.


On Wed, 25 Sep 2019 at 23:17, Martin Maher <gentoo at penguindreams.us> wrote:

> Stian:
>
> In reading this thread and the OPs concerns, I see three components that
> could exert or express control - the Keycloak server; the application
> server; and the user.
>
> From reading the OPs concerns, both in the original post and in the later
> articulation, it seems as though there is a desire to have the user express
> what is a high-risk API . . . "*Therefore end-user wants to
> re-authenticate periodically*”, versus your example of the Application
> server designating itself as a high-risk for all users.
>
> I agree with your assertion that solving this issue through HTTP
> session-timeouts would be problematic, not least of all for SSO type of
> authentications.
>
> Having the application server specify to the Keycloak server the
> max-length of a valid authorization based upon successful authentication,
> would permit the Keycloak server to set the “max-age” attribute, whereby
> refresh tokens would no longer be issued or honored after that time,
> leading to a requirement to reauthenticate.
>
> The tricky bit for the OPs scenario is creating a method within the
> application server for the user to express this to the application, which
> could then be conveyed to Keycloak, which could then be set on the user
> tokens.
>
> This does lead back to the application server, as you asserted, but I
> believe that there would need to be a mechanism, if one does not already
> exist, for the application server to communicate this to Keycloak on a
> per-user basis.  It should also be possible for the Keycloak server to take
> a configuration element that permits designation of high-risk and low-risk
> APIs, in order to interfere with attempts to downgrade authentication
> strengths  for sensitive applications.
>
> I hope this makes sense.
>
> Regards,
>
> Martin
>
> On Sep 24, 2019, at 23:55 , Stian Thorgersen <sthorger at redhat.com> wrote:
>
> I don't understand what's different with your use-case compared to what I
> listed. As I understand it they are both pretty much the same use-case.
>
> In either case different sessions and timeouts are not the correct
> solution. Configurable refresh token timeout is probably not a good
> solution either, at least not on its own without anything else.
>
> On Wed, 25 Sep 2019 at 03:05, 田畑義之 / TABATA，YOSHIYUKI <
> yoshiyuki.tabata.jy at hitachi.com> wrote:
>
> So trying to understand your use-case and simplifying things a bit. You
>
> basically have two (or more) different groups of APIs. Let's call these
> low-risk APIs and high-risk APIs. When a user invokes the low-risk API they
> don't need to authenticate regularly and a session can last for days (or
> weeks). For high-risk APIs they need to authenticate more regularly.
>
>
>
> This example is a little bit unfitted for our use case.
>
> I give a concrete example.
>
>
>
> For example, there are 2 client applications.
>
> Client application A accesses high-risk APIs such as money transfer API.
>
> Client application B accesses low-risk APIs such as balance inquiry API.
>
>
>
> In client application A case, it's risky for an end-user to let the client
> application to hold a valid refresh token long time because a risk
> increases which an attacker sends money using the stolen mobile devices or
> which an attacker steals the valid refresh token. Therefore end-user wants
> to re-authenticate periodically and the client application guarantees to
> end-user that it holds a valid refresh token only limited short time.
>
>
>
> In client application B case, it's not risky for an end-user to let the
> client application to hold a valid refresh token long time because it is
> not much impact for end-user that an attacker checks end user's balance.
> Therefore end-user does not want to re-authenticate periodically and the
> client application holds a valid refresh token long time prioritizing
> usability.
>
>
>
> In the above use case, end-user does not trust client applications
> completely, so it's meaningless that client application defines the
> expiration of a refresh token. And it's meaningful that authorization
> server (Keycloak) defines the expiration of a refresh token.
>
>
>
> Regards,
>
> Yoshiyuki Tabata
>
> Hitachi, Ltd.
>
>
>
> *From:* Stian Thorgersen <sthorger at redhat.com>
> *Sent:* Tuesday, September 24, 2019 4:45 PM
> *To:* TABATA，YOSHIYUKI <yoshiyuki.tabata.jy at hitachi.com>
> *Cc:* keycloak-dev <keycloak-dev at lists.jboss.org>
> *Subject:* [!]Re: Re: [keycloak-dev] Override Refresh token lifespan per
> client
>
>
>
> So trying to understand your use-case and simplifying things a bit. You
> basically have two (or more) different groups of APIs. Let's call these
> low-risk APIs and high-risk APIs. When a user invokes the low-risk API they
> don't need to authenticate regularly and a session can last for days (or
> weeks). For high-risk APIs they need to authenticate more regularly.
>
>
>
> Now this is solved with looking at when the user last authenticated as
> well as how the user was authenticated, not by having different session
> timeouts. As we don't have step-up autentication support right now, that
> leaves us with requiring users to re-authenticate more regularly for the
> high-risk API.
>
>
>
> Conceptually I can see at least two different ways to achieve the above:
>
>
>
> 1) Resource Server is responsible for verifying - the UI uses login=promt
> and/or max_age to re-authenticate the user when needed. Further, the
> resource server needs to check when user authenticate.
>
> 2) Keycloak is responsible for verifying - perhaps Keycloak issues refresh
> tokens with shorter duration for specific apps/UIs
>
>
>
> Option 2 is problematic as the UI may just as well invoke both low-risk
> and high-risk APIs. Further, in the future as we add step-up, high-risk may
> be asking for step-up authentication, not re-authentication.
>
>
>
> On Tue, 24 Sep 2019 at 07:46, TABATA，YOSHIYUKI <
> yoshiyuki.tabata.jy at hitachi.com> wrote:
>
> For authorization code flow it makes no sense at all to have different
>
> session timeouts as it is by definition a shared SSO session. Different
> security levels should be controlled things like step-up and authentication
> timeout, not by having different session timeouts. Further, I'm not sure if
> refresh token timeout should be configurable per-client here as end of the
> day a new refresh token can easily be obtained as long as the session is
> still active.
>
>
>
> Clients guarantee to end-users that clients access to end-users' resources
> only within the expiration using the tokens. So end-users need to re-login
> after the expiration and clients must not refresh tokens after the
> expiration.
>
> The expiration depends on each client by security reason, or usability
> reason, or so on.
>
> Therefore regardless of which authorization flows we use, we need to make
> a difference between session timeouts.
>
>
>
>
>
> I'm not particularly found of introducing so many settings on a client.
>
> It's difficult to setup and error prone. So this use-case needs to be
> described properly and we need to find a decent solution to it. Simply
> adding all these settings on a client may work for you, but I doubt others
> would understand how and when to use them, and I think it can easily end up
> resulting in a lot of error cases.
>
>
>
> How about providing a checkbox which enables a one-to-one relationship
> between UserSessionModel and ClientSessionModel?
>
> Currently, UserSessionModel and ClientSessionModel are a one-to-many
> relationship, and this makes it difficult to set session timeout per
> client.
>
> If the checkbox enabled, not link a new ClientSessionModel to the existing
> UserSessionModel when a new client which uses the existing authentication
> result appeared but make a new UserSessionModel.
>
> If this possible, we don't need to change the way to manage sessions.
>
>
>
> Keycloak is a SSO solution and we have no plans on introducing per-client
> sessions.
>
>
>
>
>
>
>
> Regards,
>
> Yoshiyuki Tabata
>
> Hitachi, Ltd.
>
>
>
> *From:* Stian Thorgersen <sthorger at redhat.com>
> *Sent:* Friday, September 20, 2019 6:00 PM
> *To:* TABATA，YOSHIYUKI <yoshiyuki.tabata.jy at hitachi.com>
> *Cc:* keycloak-dev <keycloak-dev at lists.jboss.org>
> *Subject:* [!]Re: [keycloak-dev] Override Refresh token lifespan per
> client
>
>
>
> I'm still not quite following what you are trying to achieve.
>
>
>
> For authorization code flow it makes no sense at all to have different
> session timeouts as it is by definition a shared SSO session. Different
> security levels should be controlled things like step-up and authentication
> timeout, not by having different session timeouts. Further, I'm not sure if
> refresh token timeout should be configurable per-client here as end of the
> day a new refresh token can easily be obtained as long as the session is
> still active.
>
>
>
> For client credentials grant where the server obtains tokens this may make
> sense.
>
>
>
> I'm not particularly found of introducing so many settings on a client.
> It's difficult to setup and error prone. So this use-case needs to be
> described properly and we need to find a decent solution to it. Simply
> adding all these settings on a client may work for you, but I doubt others
> would understand how and when to use them, and I think it can easily end up
> resulting in a lot of error cases.
>
>
>
> On Fri, 20 Sep 2019 at 08:40, TABATA，YOSHIYUKI <
> yoshiyuki.tabata.jy at hitachi.com> wrote:
>
> Hello,
>
> In cloud-native application systems, there are various client applications
> and those applications are not the same level (i.e. security level,
> alliance level, development level). And generally, a realm manager or a
> resource server manager wants to set a different timeout to tokens (access
> token/refresh token) per client. For example, for a client which wants to
> minimize authentication considering usability, we set the timeout of a
> refresh token longer enough. For a client which wants to refresh tokens
> periodically to mitigate the token interception attack, we set the timeout
> of a refresh token according to the client requirement.
>
> Currently, the timeout of an access token can be overridden per client.
> However, the timeout of a refresh token (including offline token) cannot be
> overridden per client.
>
> We'd like to be able to override the timeout of a refresh token (including
> offline token) per client.
>
> We'd already tried to implement this just like access token lifespan
> overriding, and create JIRA ticket and PR, but Stian recommended that we
> should discuss this use case and how to implement in ML, so I opened this
> thread.
>
> For single sign-on purpose, it is useful to share sessions among clients
> in a realm.
> However, when we implement this, sessions are no longer shared among
> clients depending on the settings. And this is useful for API management
> purpose because, for API management purpose, tokens (= sessions) are
> associated with each client, and should be managed per client.
>
> What do you think about this feature? I would be very happy if you
> community gives any kind of comment on that.
>
> JIRA ticket is the following.
> https://issues.jboss.org/browse/KEYCLOAK-10907
> <
> https://clicktime.symantec.com/3XksWm4odSS8VwXNrH1nE8Q7Vc?u=https%3A%2F%2Fissues.jboss.org%2Fbrowse%2FKEYCLOAK-10907
> >
>
> PR is the following.
> https://github.com/keycloak/keycloak/pull/6309
> <
> https://clicktime.symantec.com/3KpbzQn7GfmuzEjrULq3CKg7Vc?u=https%3A%2F%2Fgithub.com%2Fkeycloak%2Fkeycloak%2Fpull%2F6309
> >
>
> Regards,
> Yoshiyuki Tabata
> Hitachi, Ltd.
>
>
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