Azure B2C is a fantastic identity and access management solution, but even the best tools can have their quirks. One such quirk is the refresh token not including custom claims. If you’re struggling with this issue, fear not! In this article, we’ll delve into the world of Azure B2C, exploring the root cause of the problem and providing a step-by-step guide to resolving it.
What are Custom Claims, and Why Do We Need Them?
Custom claims are additional pieces of information that can be included in an Azure B2C token to provide more context about the user. These claims can be used to store application-specific data, such as user roles, preferences, or other details that are not part of the standard Azure B2C payload.
In a typical authentication flow, Azure B2C issues an access token that contains a set of standard claims, such as the user’s name, email, and ID. However, when it comes to refresh tokens, things get a bit more complicated.
The Problem: Refresh Tokens Without Custom Claims
When you request a refresh token from Azure B2C, it’s not uncommon to find that the custom claims are missing from the token. This can be frustrating, especially if your application relies on these claims to function properly.
But why does this happen? The reason lies in how Azure B2C handles refresh tokens.
refresh_tokens are designed to be long-lived, allowing users to maintain access to resources even when their session has expired. To ensure security, Azure B2C doesn’t store the full set of claims in the refresh token. Instead, it only includes the necessary information to authenticate the user and issue a new access token.
This approach has a side effect: custom claims are not included in the refresh token by default.
Solving the Mystery: Steps to Include Custom Claims in Refresh Tokens
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Configure Azure B2C to include custom claims in the refresh token
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Update your application code to request the custom claims
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Verify that the custom claims are included in the refresh token
Step 1: Configure Azure B2C to Include Custom Claims
To include custom claims in the refresh token, you’ll need to update your Azure B2C policy.
<BuildingBlocks>
<ClaimsSchema>
<ClaimType Id="customClaim">
<DisplayName>Custom Claim</DisplayName>
<DataType>string</DataType>
</ClaimType>
</ClaimsSchema>
</BuildingBlocks>
<ClaimsProvider>
<DisplayName>Custom Claims</DisplayName>
<TechnicalProfiles>
<TechnicalProfile Id="CustomClaims">
<Protocol Name="OpenIdConnect" />
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="customClaim" />
</OutputClaims>
</TechnicalProfile>
</TechnicalProfiles>
</ClaimsProvider>
<RelyingParty>
<TechnicalProfile Id="PolicyProfile">
<Protocol Name="OpenIdConnect" />
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="customClaim" AlwaysIncludeInToken="true" />
</OutputClaims>
</TechnicalProfile>
</RelyingParty>
In this example, we’ve added a custom claim type called customClaim and included it in the OutputClaims section of the relying party policy.
Step 2: Update Your Application Code to Request Custom Claims
Next, you’ll need to update your application code to request the custom claims from Azure B2C.
In your Azure B2C authentication flow, add the custom claim to the scope parameter:
https://login.microsoftonline.com/{tenantId}/oauth2/v2.0/token?
client_id={clientId}&
scope=openid+profile+email+customClaim&
response_type=code&
redirect_uri={redirectUri}&
state={state}&
nonce={nonce}
By including the custom claim in the scope, Azure B2C will include it in the access token and refresh token.
Step 3: Verify Custom Claims are Included in the Refresh Token
Finally, verify that the custom claim is included in the refresh token by examining the token using a tool like jwt.io.
{
"exp": 1623456789,
"nbf": 1623456789,
"ver": "2.0",
"iss": "https://login.microsoftonline.com/{tenantId}/",
"aud": "{clientId}",
"iat": 1623456789,
"auth_time": 1623456789,
"nonce": "{nonce}",
"customClaim": "Custom Claim Value"
}
If everything is configured correctly, you should see the custom claim included in the refresh token.
Troubleshooting Tips and Tricks
If you’re still struggling to get custom claims included in your refresh tokens, here are some troubleshooting tips to keep in mind:
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Double-check your Azure B2C policy configuration to ensure that the custom claim is included in the output claims.
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Verify that the custom claim is being requested in the scope parameter of your authentication flow.
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Use a tool like Fiddler or Postman to inspect the HTTP requests and responses to ensure that the custom claim is being sent and received correctly.
-
Check the Azure B2C error logs to see if there are any errors related to the custom claim.
Conclusion
In this article, we’ve explored the mysterious case of the missing custom claims in Azure B2C refresh tokens. By configuring Azure B2C to include custom claims, updating your application code to request them, and verifying their inclusion in the refresh token, you can ensure that your application has access to the necessary information to function properly.
Remember to keep your Azure B2C policies and application code up-to-date to ensure that custom claims are included in refresh tokens. With a little patience and persistence, you’ll be able to uncover the secrets of Azure B2C and build applications that are both secure and functional.
| Tip | Description |
|---|---|
| Use a token debugger | Tools like jwt.io or token debugger can help you examine the contents of your Azure B2C tokens, including refresh tokens. |
| Verify policy configuration | Double-check your Azure B2C policy configuration to ensure that custom claims are included in the output claims. |
| Request custom claims in scope | Make sure to include the custom claim in the scope parameter of your authentication flow. |
By following these tips and best practices, you’ll be well on your way to resolving the mystery of the missing custom claims in Azure B2C refresh tokens.
Frequently Asked Question
Got stuck with Azure B2C and custom claims in refresh tokens? Don’t worry, we’ve got you covered!
Why doesn’t my refresh token include custom claims?
By default, Azure B2C only includes the standard claims in the refresh token. Custom claims are not included unless you specifically configure the token issuance policy to include them. To do this, you need to add the custom claims to the token configuration in the Azure B2C portal.
How do I configure the token issuance policy to include custom claims?
To include custom claims in the refresh token, you need to add a custom claim to the token configuration in the Azure B2C portal. Go to the Azure B2C portal, navigate to the “Token, session & config” section, and click on “Token configuration”. Then, click on “Add optional claim” and select the custom claim you want to include. Finally, save the changes and update the token issuance policy.
What are the implications of not including custom claims in the refresh token?
If you don’t include custom claims in the refresh token, your application may not be able to access the claims when the access token is refreshed. This can lead to authorization issues or errors in your application. Moreover, if you’re using custom claims to store sensitive information, not including them in the refresh token can compromise the security of your application.
Can I include custom claims in the id token instead?
Yes, you can include custom claims in the id token instead of the refresh token. However, keep in mind that the id token is meant to contain information about the user’s identity, while the refresh token is meant to contain information about the user’s session. Including custom claims in the id token may not be suitable for all scenarios, and you should consider the security implications of doing so.
What are some best practices for handling custom claims in Azure B2C?
Some best practices for handling custom claims in Azure B2C include: using a clear and consistent naming convention for custom claims, storing sensitive information securely, and limiting the number of custom claims to only those necessary for your application. Additionally, consider implementing a token caching mechanism to reduce the number of token requests and improve performance.
