I have a JWT token which is generated client side and stored in session storage. It is passed to ASP.NET WebApi endpoints that are decorated with the Authorize attribute. If a user signs out of my application then I can delete the token and sign the user out of Azure.
However if the user goes to a different Azure site and signs out then the token that is used in my application remains valid (despite the user being signed out.) How can I force WebApi to call back to Azure and revalidate the token on each request?
Thanks,
Joe
Azure AD JWT access tokens are self signed and the payload contains the exp timestamp, datetime until which the token is valid. The relying party application does not communicate with Azure AD to validate the token, instead, it uses the self-signed information.
The only way to log out, as you mention, is to delete the token.
When you log out from Azure AD SSO you only log out of the possibility to create new access tokens, but already issued access tokens will continue to work until they expire.
Try to log out from Azure AD SSO but keep the access token to your application: You will still be able to access it.
So if you want to log out from both applications, you will need to delete access tokens for both applications.
Related
I have a scenario whereby, a user would sign in/sign up to Azure AD B2C from a frontend application. There after they would make calls to an API application (with a JWT token) separate from this frontend. The requirement is that the API application validates a user's token and decides whether to execute the request. I can send the JWT token from frontend to API using the auth header. I can receive it in the API also. The challenge is to now validate that this token is not faked by a man-in-the-middle or just being abused by someone who got hold of it. I know each token comes with a timestamp and can be checked for expiration. However, this is not sufficient. I need to check it against Azure AD B2C somehow.
Update: the API is a NodeJs based Azure Functions app
You can validate the signatures of the token in your API app. A Token is signed by asymmetric keys.
Every user flow in AzureB2C has a associated metadata document which has all the details about the keys in the tag "jwks_uri"
"jwks_uri": "https://xxxxxx.b2clogin.com/xxxxxxxxx.onmicrosoft.com/discovery/v2.0/keys?p=b2c_1_pe",
you can fetch the key details from the link under jwks_uri tag and use it to validate the signature. Also remember these keys are rotated so you need to get the latest once every 24 hours.
Sample :-
https://github.com/azure-ad-b2c/samples/tree/master/policies/user_info
Doc https://learn.microsoft.com/en-us/azure/active-directory-b2c/tokens-overview
See this sample. The API is protected using the UseOAuthBearerAuthentication to verify the signature of the token. All Azure AD B2C tokens are signed JWTs. The sample code will find the metadata endpoint of your policy+tenant combination, and use the public key to ensure that the token signature is valid/unmodified and has been signed by the private keyholder (AAD B2C)
I am using vue-adal library in my VueJS application to connect to Azure AD.
AD Token valid for 1hr after login.
When my token expires i am unable to renew it from client side.
Is there any way to renew token from client side using VueJS or
Any other alternate approach can be used for this scenario?
Thanks,
Gowtham
Since you are using implicit flow, azure AD will not return refresh token in implicit flow for you to refresh the token. As per this documentation, here is the recommended approach for this.
A JavaScript application has another mechanism at its disposal for
renewing access tokens without repeatedly prompting the user for
credentials. The application can use a hidden iframe to perform new
token requests against the authorization endpoint of Azure AD: as long
as the browser still has an active session (read: has a session
cookie) against the Azure AD domain, the authentication request can
successfully occur without any need for user interaction.
I already made the authentication flow with the Microsoft Graph/Azure AD authentication. Once I get the authenticated user's token I store them in his cookies. To validate the user's token I call the Microsft Graph API resource /me. This does not seem a good approach because basically everytime time a client does a request to my API, he is basically doing 2 requests because my API requests Azure AD for validation.
Is this a good flow?
No, it isn't.
Your front-end should acquire an access token for your API, which the API can verify using its digital signature.
The token will contain some info about the user as well as the app that acquired it.
The way in which the front-end acquires the token depends on the type of application.
Front-end single page apps use implicit grant flow for example.
Do note that you have to specifically ask for an access token for your API.
As long as your back-end is then configured with standard JWT Bearer authentication,
all is handled.
This is done by specifying the authority as your Azure AD tenant (or the common endpoint if it's multi-tenant),
and the standard bits for JWT authentication should download the public keys from Azure AD's metadata endpoint, which it can then use to verify validity of any access token it receives.
You do not have to validate tokens for an api that's not yours (issued to your AppId Uri).
For example, Graph validates the tokens that are sent to it (issued for "https://graph.microsoft.com).
If you build and register in Azure AD an Api of your own (say AppIdUri="https://myapi.mydomain.com"), your clients will request and receive access tokens with aud claim set to "https://myapi.mydomain.com".
The clients themselves don't need to validate the access token issued for your Api But your Api, when it receives those access tokens, has to validate them. The validations, among other things will validate the access token was issued to "https://myapi.mydomain.com".
Try out this sample, to get a good understanding around concepts of token validation.
I need clarification with sample or reference link for below items:
How to enable automatic renewal of access token?
How to get active access token and expiry time ?
Is there any possible ways to get Ad username, password and client id again from access token?
How to validate access token ?
It all needs to be implement in c# not in powershell.
How to enable automatic renewal of access token?
Upon successful authentication , Azure AD returns two tokens: a JWT access token and a JWT refresh token .When the access token expires, the client application will receive an error that indicates the user needs to authenticate again. If the application has a valid refresh token, it can be used to acquire a new access token without prompting the user to sign in again. If the refresh token expires, the application will need to interactively authenticate the user once again.
How to get active access token and expiry time ?
For how to authenticate users and get an Azure AD access token for your azure ad app , you could refer to Authentication Scenarios for Azure AD .The Azure Active Directory Authentication Library (ADAL) enables client application developers to easily authenticate users to cloud or on-premises Active Directory (AD), and obtain access tokens for securing API calls. ADAL is available on a variety of platforms. You could find code samples and common scenario in this document .
Is there any possible ways to get Ad username, password and client id again from access token?
You could get decode the access token , find the upn claim which Stores the user name of the user principal ; appid claim identifies the application that is using the token to access a resource. Please refer to document :Azure AD token reference .And of course ,you can't get password information .
How to validate access token ?
JWT tokens are signed, but not encrypted when received. It must validate the signature to prove the token's authenticity and validate a few claims in the token to prove its validity. The claims validated by an app vary depending on scenario requirements, but there are some common claim validations that your app must perform in every scenario.For example, we need to verify the iss and aud claim if you were developing a single tenant app. And you also need to verify the nbf to ensure the token is not expired. For more details , please refer to Validating tokens .
Here is a code sample for how to manually validating a JWT access token in a web API . And if you were using the OWIN components in your project, it is more easy to verify the token by using UseWindowsAzureActiveDirectoryBearerAuthentication extension , code sample here is for your reference .
I am trying to gather metrics info of azure resources. For that i need an access token to authorize. But to get an access token i have to give client id, client secret, subscription id, tenant id.I was wondering if i could get this access token without giving so many details except username and password of my azure account.
Basically you need the parameters. Azure's APIs are protected by Azure AD so you have to authenticate against it first. If you want to make calls as the user, you still need to authenticate with one of the few ways available. The password grant (as shown in #4c74356b41 answer) is one option, though it is not really recommended. The reason is that if the user's password has expired or has MFA enabled, it won't work.
What you usually do is request the user to login via Azure AD sign-in page (via redirect or web view), and then exchange the resulting authorization code for an access token and refresh token. Then you can make calls against the APIs as the user.
Another option is to register your app in Azure AD and grant its service principal some roles in your Azure subscriptions/resource groups/resources. Then it can authenticate with client credentials (using only its client id and secret + your Azure AD tenant id).
it is possible, but it is considered not safe. And you would still need a lot of parameters:
Name Description
grant_type The OAuth 2 grant type: password
resource The app to consume the token, such as Microsoft Graph, Azure AD Graph or your own Restful service
client_id The Client Id of a registered application in Azure AD
username The user account in Azure AD
password The password of the user account
scope optional, such as openid to get Id Token
Reference:
https://blogs.msdn.microsoft.com/wushuai/2016/09/25/resource-owner-password-credentials-grant-in-azure-ad-oauth/
ps. Don't mind Walter, he is wrong like 50% of the time in his answers.
It really depends on your need and if you want this fully automated or not.
If you want to have a token for a ServicePrincipal, the answer of 4c74356b41 is a great way to do it.
However if you would want to obtain a bearer token for a user (you or another AAD user) that is already authenticated in a PowerShell session, you could do this very easily if you use this piece of code that I wrote.
https://gallery.technet.microsoft.com/scriptcenter/Easily-obtain-AccessToken-3ba6e593
Basically what it does, it fetch the current token from the token cache and return it to you. This way you don't have to deal with clientId, cliendSecret or certificate. I use this all the time when I need to call the Azure REST API on a Just In Time fashion.