Which MSAL Authentication Flow? - oauth-2.0

I built a SaaS application that needs to retrieve all our customer's Users & Groups from Microsoft Graph daily.
The setup part can be interactive but the Microsoft Graph is not (as it is a background task on the server-side).
I have a hard time understanding which flow I should use. When I look at the list of Authentication flows (https://learn.microsoft.com/en-us/azure/active-directory/develop/msal-authentication-flows), I see naturally the Client credentials flow recommended for daemons apps. However, the drawback seems the setup complexity. The administrator needs to manually register an app, generate the secret, etc. which I would like to avoid.
On the other hand, I see the other flows (Authorization code, etc.) where there is a very streamlined authentication process. It seems that I can store on the backend side the refresh token and use it from the backend in a daemonize way. It seems to be the best of both worlds. Is this pattern correct? Is it reliable?
Note: My SaaS has a UI and users can log in to it during the setup part.

The administrators won't need to install your app manually and generate the secret. It's you who generates the secret for your server side and you will use your client ID and the secret to access Graph in offline mode. For that you'll need your clients' administrators' consent which you can get by redirecting them to admin consent page which will present the list of permissions required by your application to access the Graph data.
All of this is described here: https://learn.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow

Related

What's the best way to use OAuth to manage access to a suite of applications?

Please forgive my ignorance on this topic. I've been a developer for a long time, but there's a huge gap in my knowledge and experience when it comes to authentication & authorization protocols and proper handling of tokens.
We've got a whole homegrown suite that consists of:
4 web apps (2 in Ruby/Rails, 1 in Elixir/Phoenix, 1 single-page React)
1 image server (serverless app written as an AWS Lambda / API Gateway)
1 custom data API (also serverless Lambda / API Gateway)
We also have an Amazon Cognito User Pool connected to our backend identity provider to authenticate users and generate tokens.
All but one of these allow some form of anonymous access; the other is only available to logged in users. If a user is logged in, they all need to access the user's profile info from the ID token, preferably without initiating another auth flow. Our backend apps may also need to make use of the access token, but obviously we wouldn't be handing that out to to the SPA or public API consumers.
My first thought is to store the tokens in a key/value store on the backend, and have a short-lived, encrypted JWT containing a unique session ID set on the shared domain that all of the backend apps have access to, with the key stored in a config secret. By decoding the session ID, they can get what they need from the data store. The API would also refresh when necessary.
I also know that API Gateway can use a Cognito user pool as an authorizer, but I'm unclear how I would make that work while integrating it with the rest of our apps and requirements above. Sometimes requests to the API are made from the browser (in the React app, for example), and sometimes they come from the backend of one of the web apps.
The image server and API are used by our apps, but are also documented and accessible for other people to build their own applications on. But they would have to register their apps as OIDC clients to receive any profile info from logged in users.
I'd love some advice on how to make all of this work, or at least pointers toward resources that might help make it less dizzying.

Is it okay to use client credentials grant type for authentication of a WEB API going to be consumed by SailPoint(IAM)

I have an old windows application written in VB.NET with SQL server backend. Currently the new user additions, deletion, adding entitlements etc. are managed by an old approval workflow system. After getting approvals, the user details and entitlements are inserted in to the SQL server database table manually.
I am trying to integrate this application with the SailPoint's Identity and access management. So the new user addition, deletion update and adding entitlements etc will be done through Sailpoint. For this, I would require to create a WEB API which can be called by Sailpoint and expose the functionalities(add user/delete user/add entitlements). The only consumer to this API is SailPoint.
I am new to OAuth and below are the grant types that I came across. But not sure which one I should be using in this particular scenario.
1.Implicit Grant
2.Resource Owner Password Credentials Grant
3.Client Credentials Grant
4.Authorization Code Grant
I have done research on the different authentication methods that we can use to secure the web api. But still confused on which one to apply in this scenario as this new web api is going to be made available in internet.
I already tried developing a POC with the OAuth 2.0 with password grant type referring this article. But when I read articles in the internet I found that the password grant type is not that secure and is deprecated.
Could you please advise on which grant type(client credentials/authorization code/implicit) to use in this scenario. I believe authorization code is used when the user is directly trying to access the API. In this scenario, SailPoint will be calling the API in the backend programmatically when they insert a new user in their UI.
I think it's a good approach to use client credentials in this case because the communication between IIQ and your Web API can be considered an API-to-API communication, I mean, IIQ is acting on behalf of itself in this communication.
See this article for more details - https://dzone.com/articles/four-most-used-rest-api-authentication-methods (bold part by myself)
OAuth 2.0 provides several popular flows suitable for different types
of API clients:
Authorization code — The most common flow, it is mostly used for
server-side and mobile web applications. This flow is similar to how
users sign up into a web application using their Facebook or Google
account.
Implicit — This flow requires the client to retrieve an
access token directly. It is useful in cases when the user’s
credentials cannot be stored in the client code because they can be
easily accessed by the third party. It is suitable for web, desktop,
and mobile applications that do not include any server component.
Resource owner password — Requires logging in with a username and
password. In that case, the credentials will be a part of the request.
This flow is suitable only for trusted clients (for example, official
applications released by the API provider).
Client Credentials —
Intended for the server-to-server authentication, this flow describes
an approach when the client application acts on its own behalf rather
than on behalf of any individual user. In most scenarios, this flow
provides the means to allow users to specify their credentials in the
client application, so it can access the resources under the client’s
control.

Correct authorization strategy using Azure AD to secure a CLI to REST API

I'm trying to implement security to a backoffice CLI tool (NodeJS) that calls a REST api (Java/JAX-RS) for performing database operations etc.
As we're using Azure AD for all our user accounts I'd like to use it for authenticating our users and also for authorization.
The authorization is needed since not all members of the AD is supposed to use the CLI, and there are two types of users of the CLI with a different set of available commands, meaning that even if you are able to use it, some features might be locked out depending if you are an operator or administrator.
I've managed to create two applications in Azure AD, one for the CLI and one for the API. I can login using our AD credentials, fetch Access tokens for the CLI app id requesting the REST API resouce. On the client side I'm using https://www.npmjs.com/package/simple-oauth2 .
On the Java side the tokens are validated against Microsoft public keys, so everything seems to work out fine.
But, how should I lock down the users to either operator or admin roles? One naive way I can think of is to have the user/role correlation in the REST API and only use the OAuth flow for authenticating the user. But I guess that's what the AD is there for... Could OAuth scopes help me in this case?
Or should the REST API call the AD to query for users group memberships, once it receives the access tokens and knows the end user identity?
Thanks in advance!
Use the Application Roles.
Here you will find good description what application roles are and how to handle them:
https://learn.microsoft.com/en-us/azure/active-directory/develop/howto-add-app-roles-in-azure-ad-apps
The recommended resources at the end and also very helpful and will guide you through the process.
Also, when developing CLI it is recommended to use the Device Flow - described here with sample code (.net core) here.

Best practice for OAuth Tokens for a combination of native apps and backend processes

I have a scenario in which a mobile (native) app is requiring data from a long running task. The task is a continuesly running on the users behalf, and we have decided to move it to a backend service. To execute the task, the backend service must regularly fetch data from an API that is OAuth2 protected.
Our dilemma is that we are not sure how to provide the backend service with a set of access tokens to access the data API. Our mobile app uses the OAuth2 Authorization Grant flow with PKCS to get its own access token, refresh token and id-token (we use OpenID Connect). But how do we provide our backend service with a set of tokens? As the backend is continuesly running (also in absence of the mobile native app) we would like to provide it with its own set of access/refresh tokens.
There seem to be several solutions:
Proxy all mobile app communication to external APIs via the backend, make the client a private client, use the authorization code flow, and setup custom login sessions between the native app and our backend. To me this means more running backend infrastructure, and implementing session management including session refresh, etc. which is like re-implementing the OpenId flows on my own servers...
Using OpenID hybrid flow, providing both an access token as well as an authorization code to be shared with the backend. However, this seems to be directed at (in-browser) web-apps, not so much native mobile apps as it based on the implicit flow and as such less secure.
Doing the authorization code flow twice on the mobile app (optionally second time with prompt=none to suppress user interaction), keeping one code for the app, forwarding the second to the backend. Then both backend and app can exchange their own codes for access tokens. This feels a bit like a hack as the backend should be a private client, not a public client. It is the approach that Google seems to advertise though in CrossClientAuth
Performing impersonation by sending the id-token to the backend which then exchanges that id-token for its own set of access/refresh tokens. Microsoft does this through the jwt-bearer grant in its "on-behalf-of" scenarios. Moreover, the token-exchange RFC seems to cover the same use-case. However, in this scenario the id-token is indirectly used as access credential, not just as a bag of claims about the user identity, which is odd in my view as access should be controlled through access tokens, is it not? Moreover, not all services should be allowed to impersonate, so I suppose this comes with additional configuration complexity.
To me it feels that I'm overlooking something, this must be a problem others have too and must have been solved before... What would be best practice in my situation?

How to leverage oauth to implement SSO for micro service apps

We want to establish SSO between microservice apps,
Eg: In a e-commerce site if user logins to main app,user should be automatically allowed to access cart app connected to it, which is a micro service.
I searched Oauth spec but I could find any relevant answer specific to my case.
some of things which differ wrt Oauth are
User need not to authorize resources(cart app) against Identify provider.it should be done seamlessly in backend.
we don't want to use outside Identify provider like facebook,google,Main app(from eg above) should act as identity provider.
Questions
1.Is there a standard way(procedure) defined in oauth to handle these kind of authentication/authorization.?
If not what are the most popular alternatives ?
Other info:
Ours apps are build using Ruby on Rails,if you know any good gems please suggest.
I found couple of questions(1,2) related to this but they much broader. Even google is also not helping,so please don't mark this question as duplicate.
If you do want to use SSO, let all your services accept the same token, returned by Authorization server when user log in. Encrypt it and put to cookies for example - in this case your web frontend will authenticate user by validating that token against Authorization server and return user-specific content.
The same applies to cart service - it can get username by token and return user-specific cart items.
Pros: User can't access other user's data by design, user logout disables every service.
Cons: You will need "superuser" or additional API for background or analytical tasks.

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