Azure AD B2C - Custom policy with HRD, Domain Hints and MFA

Question

I'm trying to build a B2C custom policy that makes use of Home-realm Discovery and Domain Hints.

We have 2 personas.

Local User that authenticates in B2C with MFA
External User that must to be redirected to their company's login page.

Use cases:

User gets redirected to https://customdomain.b2clogin.com (no domain hint). User gets presented with a Login page asking for the email address and depending on type of user:
- A local user to B2C authenticates in our B2C page (customdomain.b2clogin.com). First, user enters email address, then on Next user enters password and finally enters code (received on phone) for MFA.
- An external user first enters their email then B2C must automatically redirect the user to the federated Identity provider to login.
User gets redirected to https://customdomain.b2clogin.com/?domain_hint=xyz.com (with domain hint)
- In this case we expect the user to be automatically redirected to xyz.com identity provider. The user should NOT see our login page for customdomain.b2clogin.com

What I have tried:

By taking the home-realm-discovery-modern sample (https://github.com/azure-ad-b2c/samples/tree/master/policies/home-realm-discovery-modern) I get HRD working properly (point 1)

By taking the SocialAndLocalAccountsWithMfa sample in the B2C starter pack I get the domain_hint redirection for free (point 2 above).

However, I'm failing at combining the two together to get both working (domain_hint and HRD).

Here is the User Journey:

    <UserJourneys>
       <UserJourney Id="SignIn">

        <OrchestrationSteps>

            <OrchestrationStep Order="1" Type="ClaimsExchange">
                <ClaimsExchanges>
                    <ClaimsExchange Id="ParseDomainHint" TechnicalProfileReferenceId="ParseDomainHint" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <OrchestrationStep Order="2" Type="ClaimsExchange">
                <Preconditions>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="true">
                        <Value>isKnownCustomer</Value>
                        <Value>True</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsExchanges>
                    <ClaimsExchange Id="SigninEmailExchange" TechnicalProfileReferenceId="SelfAsserted-Signin-Email" />
                </ClaimsExchanges>
            </OrchestrationStep> 

            <OrchestrationStep Order="3" Type="ClaimsExchange">
                <Preconditions>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="true">
                        <Value>isKnownCustomer</Value>
                        <Value>True</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsExchanges>
                    <ClaimsExchange Id="ParseDomainHintLogic" TechnicalProfileReferenceId="HRDLogic" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <!-- If the domain_hint did not match any known domain, then redirect to a default local account sign in-->
            <OrchestrationStep Order="4" Type="CombinedSignInAndSignUp" ContentDefinitionReferenceId="api.signuporsignin">
                <Preconditions>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="true">
                        <Value>isKnownCustomer</Value>
                        <Value>True</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsProviderSelections>
                    <ClaimsProviderSelection ValidationClaimsExchangeId="LocalAccountSigninEmailExchange" />
                </ClaimsProviderSelections>
                <ClaimsExchanges>
                    <ClaimsExchange Id="LocalAccountSigninEmailExchange" TechnicalProfileReferenceId="SelfAsserted-LocalAccountSignin-Email" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <!-- dont run this step if the domain was known, or we have an objectid (local account sign in)-->
            <OrchestrationStep Order="5" Type="ClaimsExchange">
                <Preconditions>
                    <Precondition Type="ClaimsExist" ExecuteActionsIf="true">
                        <Value>objectId</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="true">
                        <Value>isKnownCustomer</Value>
                        <Value>true</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsExchanges>
                    <ClaimsExchange Id="SignUpWithLogonEmailExchange" TechnicalProfileReferenceId="LocalAccountSignUpWithLogonEmail" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <!-- If the domain matched any known domain, then this step will have a single IdP
                enabled due to each known IdP TP having an enablement flag via identityProviders claim -->
            <OrchestrationStep Order="6" Type="ClaimsProviderSelection" ContentDefinitionReferenceId="api.idpselections">
                <Preconditions>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="false">
                        <Value>isKnownCustomer</Value>
                        <Value>True</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsProviderSelections>
                    <ClaimsProviderSelection TargetClaimsExchangeId="AADOIDC" />
                    <ClaimsProviderSelection TargetClaimsExchangeId="MSAOIDC" />
                </ClaimsProviderSelections>
            </OrchestrationStep>

            <OrchestrationStep Order="7" Type="ClaimsExchange">
                <Preconditions>
                    <Precondition Type="ClaimsExist" ExecuteActionsIf="true">
                        <Value>objectId</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="false">
                        <Value>isKnownCustomer</Value>
                        <Value>true</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsExchanges>
                    <ClaimsExchange Id="AADOIDC" TechnicalProfileReferenceId="AAD-OIDC" />
                    <ClaimsExchange Id="MSAOIDC" TechnicalProfileReferenceId="MSA-OIDC" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <!-- For social IDP authentication, attempt to find the user account in the directory. -->
            <OrchestrationStep Order="8" Type="ClaimsExchange">
                <Preconditions>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="false">
                        <Value>isKnownCustomer</Value>
                        <Value>True</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsExchanges>
                    <ClaimsExchange Id="AADUserReadUsingAlternativeSecurityId" TechnicalProfileReferenceId="AAD-UserReadUsingAlternativeSecurityId-NoError" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <!-- Still dont have objectId (social idp user that doesnt yet exist) - write the account -->
            <OrchestrationStep Order="9" Type="ClaimsExchange">
                <Preconditions>
                    <Precondition Type="ClaimsExist" ExecuteActionsIf="true">
                        <Value>objectId</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsExchanges>
                    <ClaimsExchange Id="AADUserWrite" TechnicalProfileReferenceId="AAD-UserWriteUsingAlternativeSecurityId" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <OrchestrationStep Order="10" Type="ClaimsExchange">
                <Preconditions>
                    <Precondition Type="ClaimEquals" ExecuteActionsIf="true">
                        <Value>isKnownCustomer</Value>
                        <Value>True</Value>
                        <Action>SkipThisOrchestrationStep</Action>
                    </Precondition>
                </Preconditions>
                <ClaimsExchanges>
                    <ClaimsExchange Id="AADUserReadWithObjectId" TechnicalProfileReferenceId="AAD-UserReadUsingObjectId" />
                </ClaimsExchanges>
            </OrchestrationStep>

            <OrchestrationStep Order="11" Type="SendClaims" CpimIssuerTechnicalProfileReferenceId="JwtIssuer" />
        </OrchestrationSteps>
        <ClientDefinition ReferenceId="DefaultWeb" />
    </UserJourney>
</UserJourneys>

What I'm I missing?

Alboz Alboz · Accepted Answer · 2021-03-02T10:25:30

We managed to get Home Realm Discovery (HRD) and Domain Hints to work together in a custom policy. It's based on the HomeRealmDiscoveryModern sample.

Here is the solution/sample: https://github.com/AlbozDroid/b2c-hrd-domainhint-sample/blob/main/Alboz_susi_public.xml

The MFA part is not there but should be easy to add by following the LocalAndSocialWithMFA sample provided by Microsoft.

Azure AD B2C - Custom policy with HRD, Domain Hints and MFA

1 Answers