WebAuthn: Issue with Fido metadata?
Philip Smart
Philip.Smart at jisc.ac.uk
Sun Nov 3 16:33:12 UTC 2024
Quick note: orchestrating it in this way, if you do ‘downgrade', it would no longer satisfy an MFA request (or similar) from the SP.
Phil
On 3 Nov 2024, at 15:04, Mats Luspa <mats.luspa at irf.se> wrote:
Yes, you are correct. In the registration process it works but not in the authentication flow where you for those without passkeys registrated go to authn/Password.
I tested with activationCondition (activate authn/Password only if no passkey is regsistrated) according to below configuration but it didn't work that either.
<bean id="authn/Password" parent="shibboleth.AuthenticationFlow"
p:passiveAuthenticationSupported="true"
p:forcedAuthenticationSupported="true"
p:activationCondition-ref="checkWebAuthnAvailability"/>
<bean id="checkWebAuthnAvailability" parent="shibboleth.Conditions.Scripted" factory-method="inlineScript">
<constructor-arg>
<value>
<![CDATA[
var webauthnRegCtx = profileRequestContext.getSubcontext(WebAuthnRegistrationContext.class);
var result = webauthnRegCtx == null || !webauthnRegCtx.isWebAuthnAvailable();
result;
]]>
</value>
</constructor-arg>
</bean>
Ok, I wait.
/Regards Mats
Den 2024-11-03 kl. 10:41, skrev Philip Smart:
On 3 Nov 2024, at 09:35, Philip Smart via dev <dev at shibboleth.net><mailto:dev at shibboleth.net> wrote:
On 2 Nov 2024, at 20:19, Mats Luspa <mats.luspa at irf.se<mailto:mats.luspa at irf.se>> wrote:
However I discovered the known issue that the username (that has no passkey) collected in the initial step is possible to alter in the authn/Password step. That means that a user with passkey can be degraded to username/password authentication.
I've tested and it works to do that.
Is it possible to secure that the username in the authn/Password step is the same as the username in the initial step? The optimal would be to only allow password input in the authn/Password step.
Yes, this should be covered by the ‘AccessByCurrentUser’ policy as shown in https://shibboleth.atlassian.net/wiki/spaces/IDPPLUGINS/pages/3879206915/WebAuthnRegistration#%5BinlineExtension%5DAccessPolicy-Configuration. Let me know if that is not working (it is working for me), as that is pretty fundamental.
Sorry, I might have answered this too quickly. I guess you mean in the authentication flow, not for registration. Yeah, this is why there is a warning about that. I will get back to you next week.,
Phil
Phil
/Regards Mats
Den 2024-11-01 kl. 14:04, skrev Philip Smart:
Excellent.
Phil
On 1 Nov 2024, at 12:01, Mats Luspa <mats.luspa at irf.se><mailto:mats.luspa at irf.se> wrote:
Hello!
Thanks, it works now as I want it to work with this configuration in mfa-authn-config.xml (nearly straightforward from documentation):
<util:map id="shibboleth.authn.MFA.TransitionMap">
<entry key="">
<bean parent="shibboleth.authn.MFA.Transition" p:nextFlowStrategy-ref="checkPasswordOrWebAuthn" />
</entry>
<entry key="authn/WebAuthn">
<bean parent="shibboleth.authn.MFA.Transition">
<property name="nextFlowStrategyMap">
<map>
<entry key="NoRegisteredWebAuthnCredentials" value="authn/Password" />
</map>
</property>
</bean>
</entry>
<!-- An implicit final rule will return whatever the final flow returns. -->
</util:map>
<bean id="checkPasswordOrWebAuthn" parent="shibboleth.ContextFunctions.Scripted" factory-method="inlineScript">
<constructor-arg>
<value>
<![CDATA[
nextFlow = "authn/WebAuthn";
// Go straight to second factor if we have to, or set up for an attribute lookup first.
webauthnRegCtx = input.getSubcontext("net.shibboleth.idp.plugin.authn.webauthn.context.WebAuthnRegistrationContext");
if (webauthnRegCtx != null) {
if (!webauthnRegCtx.isWebAuthnAvailable()){
nextFlow = "authn/Password";
}
}
nextFlow; // pass control to second factor or end with the first
]]>
</value>
</constructor-arg>
</bean>
and of course NoRegisteredWebAuthnCredentials is configured in authn-events-flow.xml.
Thanks for the advice!
/Regards Mats
On 2024-10-31 12:22, Philip Smart wrote:
On 31 Oct 2024, at 07:58, Mats Luspa <mats.luspa at irf.se><mailto:mats.luspa at irf.se> wrote:
Maybe I should rephrase the question.
I wonder if it's possible to use webauthn/MFA always even if the SP is not requiring that?
Yes, if that is your only configured authentication flow.
I was thinking this scenario:
If the user enters the SP the user gets the webauthn/MFA interface in passwordless flow. Enters the username and if the user does not have any passkey registered the user comes to username/password flow if the SP is not requiring webauthn, otherwise if SP is requiring webauthn the resource is not accessible for the user. If the user has passkey registered the login is proceeding in the usual way for passkey login.
I see. You should be able to make that switch using the approach I mentioned (linked previously): if no FIDO credentials are registered, signal that to the MFA flow and then switch to the username/password flow. If the SP has signalled it wants MFA (I can not see an SP would specifically request a WebAuthn authentication method), but the user only uses a password, the IdP would not be able to satisfy the request, and so an error will be returned to the SP. If the SP had not requested MFA (or anything), and Password was sufficient, authentication will succeed. You could, of course, allow a fallback to username/password plus some other second factor (TOTP, and Duo are some options in the IdP), which could also satisfy a request for MFA from the SP.
Noting, you decide if you want to assert WebAuthn authentication as multi-factor. There are some warnings about that on this page: https://shibboleth.atlassian.net/wiki/spaces/IDPPLUGINS/pages/3878256667/WebAuthnAuthentication#%5BinlineExtension%5DAuthentication-Context-Classes-(Supported-Principals). The authentication assurances of ‘passkeys’ are changing all the time, e.g. they can be synchronised between devices and, soon, exported and transferred between providers (Credential Exchange Protocol). Of course, you could restrict users to certain ‘strong’ or trusted authenticators, e.g., hardware security keys—you can do that with the latest release candidate.
Phil
/Regards Mats
On 2024-10-30 10:48, Philip Smart wrote:
On 30 Oct 2024, at 09:22, Mats Luspa via dev <dev at shibboleth.net><mailto:dev at shibboleth.net> wrote:
Hello again!
Is it possible to configure so the authentication process falls back to username/password if a passkey can't be discovered? Right now passkey is used only if the SP requires that. But most of the SP:s at least here don't require passkeys and hence username/password is used. I want the idp to decide that passkey should be used if possible (passkey is discovered).
I guess this depends on what you mean by ‘discovered’. If you mean; does the user have a passkey registered with the IdP, then there are some options to signal ‘no passkeys’ to the MFA flow during authentication. You can then use MFA logic to decide what to do next. The docs need work, but this should be described in https://shibboleth.atlassian.net/wiki/spaces/IDPPLUGINS/pages/3878256667/WebAuthnAuthentication#%5BinlineExtension%5DSignalling-custom-events-when-the-user-has-no-registered-credentials. Please note the warning about enabling that feature (in the yellow box).
Or maybe you meant something else?
Phil
/Regards Mats
On 2024-10-30 07:24, Mats Luspa via dev wrote:
You are absolutely correct. irfAuthorizedService is an ldap attribute not resolved. I have now made a scripted attribute that checks if irfAuthorizedService contains shibAdmin and it works now.
Thanks for pointing med to the right direction :)
/Regards Mats
On 2024-10-29 21:35, Michael Grady via dev wrote:
On Oct 29, 2024, at 2:46 PM, Cantor, Scott via dev <dev at shibboleth.net><mailto:dev at shibboleth.net> wrote:
I think it has to do with that irfAuthorizedService is a multi
-value attribute.
It doesn't.
Yes the example I supplied (and that is from a working deployment), the attribute we used could have dozens and dozens of values, so multi-valued is most definitely not the issue.
--
Michael A. Grady
IAM Architect, Unicon, Inc.
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Mats Luspa
Phone: +46 (0)980 79 022
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Mats Luspa
Phone: +46 (0)980 79 022
Cellular phone: +46 (0)725813330
Institutet för rymdfysik Fax: +46 (0)980 79 050
Swedish Institute of Space Physics email: matsl at irf.se<mailto:matsl at irf.se>
Visiting/Delivery address: Bengt Hultqvists väg 1, SE-981 92 Kiruna
Postal address: Box 812, SE-981 28 Kiruna
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Digital vcard: https://www.irf.se/vcard/mats.luspa
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Mats Luspa
Phone: +46 (0)980 79 022
Cellular phone: +46 (0)725813330
Institutet för rymdfysik Fax: +46 (0)980 79 050
Swedish Institute of Space Physics email: matsl at irf.se<mailto:matsl at irf.se>
Visiting/Delivery address: Bengt Hultqvists väg 1, SE-981 92 Kiruna
Postal address: Box 812, SE-981 28 Kiruna
--
PGP Public Key: https://www.irf.se/pgp/matsl
Digital vcard: https://www.irf.se/vcard/mats.luspa
--
--
Mats Luspa
Phone: +46 (0)980 79 022
Cellular phone: +46 (0)725813330
Institutet för rymdfysik Fax: +46 (0)980 79 050
Swedish Institute of Space Physics email: matsl at irf.se<mailto:matsl at irf.se>
Visiting/Delivery address: Bengt Hultqvists väg 1, SE-981 92 Kiruna
Postal address: Box 812, SE-981 28 Kiruna
--
PGP Public Key: https://www.irf.se/pgp/matsl
Digital vcard: https://www.irf.se/vcard/mats.luspa
--
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