Thinktecture IdentityServer with ASP.NET Identity - already authenticated user - thinktecture-ident-server

I'm creating an OpenId Connect host using IdentityServer v3, backed by ASP.NET Identity.
In cases where the user is already logged in to the host application using ASP.NET Identity, how can I use the existing session, rather than prompting the user to log in again?
An example is if you are already logged in to your Google account, and you navigate to https://jabbr.net/, you will find that Google does not prompt you to enter your username and password in order to authenticate through Google.

IdentityServer will not prompt your for credentials when there is an existing authentication session - IOW a cookie. Check if this cookie is present or maybe lost somehow. By default the cookie is only valid as long as the browser window is not closed.
IdSrv3 beta 2 also has a persistent cookie feature now -
https://identityserver.github.io/Documentation/docs/configuration/authenticationOptions.html

Related

IdentityServer4 - Login via ADFS without logon prompt appearing

With the use of IdentityServer4 and the OIDC protocol, I've managed to get my SPA and my .net core web api authenticating against a sql server user store, as well as ADFS which is great. However, when the user first clicks the 'Continue with ADFS' button, the login prompt is shown asking the user for their credentials. My understanding was that with the use of openId connect and IdentityServer, we could add external identity providers such as ADFS to our IdentityServer application and if ADFS is chosen for login with the user already logged in to ADFS via their local machine, then the authentication would happen seamlessly without the need to input windows user credentials again. There are other steps in order to achieve this of course, like linking the ADFS UserId with our SQL Database User Id table, but overall my understanding was that this would be entirely possible.
After a user logs out from an ADFS login, the next time the user chooses to log back in with ADFS, the 'Challenge' method that is run within my IdentityServer application to initiate the redirect to ADFS often recognises that the user has already logged in recently and therefore just logs them right in without the need for their credentials again.
My question is - is it actually possible to avoid the initial login prompt altogether? Or will the browser insist that credentials are provided if the user hasn't logged into the application for a while?
It certainly is possible but it may involve specific browser config in ADFS and also may require your IDP to be in the intranet zone in Windows Internet settings.
Check out these articles:
https://learn.microsoft.com/en-us/windows-server/identity/ad-fs/operations/configure-intranet-forms-based-authentication-for-devices-that-do-not-support-wia
https://learn.microsoft.com/en-us/windows-server/identity/ad-fs/operations/configure-ad-fs-browser-wia

Authenticating multiple web applications through single authentication mechanism

How can I authenticate multiple applications with a single authentication mechanism?. These applications are having existing authentication within them, perhaps I need to authenticate these apps into my system which is isolated from others. Please suggest a better approach
When using OpenID Connect, the first application the user logs in to, will redirect the user's browser to the authorization server (AS). Since the user does not have a session between the browser and the AS, it will present the login screen. The user signs in and is redirected to the application (client) with an ID token and access token. The application will then establish a session between the browser and the application (typically a cookie)
When the user navigates to the second application, it will also redirect the user to the AS, but now the user already has a valid session between the browser and the AS, so the AS won't show the login screen (it may show the consent screen if the user has not consented to the requested scopes), and will issue an ID token and access token to the second application.
Now the user has a authenticated session with both applications with a single sign on (SSO).
If you use OAuth 2.0 with OIDC, you can authenticate your user once and verify the access token at each app the user visits. This is a typical single sign-on flow (SSO).

oAuth2 SSO without Cookie

We're having a native iOS and Android app that has a custom login form to authenticate a user directly via an authentication endpoint of an oAuth2 enabled indentity provider (the app sends the user credentials via HTTP request to the identity provider and gets a JWT as response).
The app does not have the possibility to open a browser with callback url or an in-app-browser to open the login form of the identity provider directly - so there is no possibility to set a cookie for SSO.
The app does sometimes redirect the user to other services (in the web browser) that are using the same identitiy provider. Until now, the user is forced to enter his credentials again to signin.
We're now looking for a (secure) way to implement SSO with the app, without the need of using a cookie enabled (in-app-)browser for the app login.
A solution we thought about:
sending a valid access_token to the identity provider together with the target url of the service
the identity provider validates the token and the target url
the identity provider authenticates the user after successfull validation and redirects the user to the service
Can this be considered as a secure solution? Is there a standardized way we don't know about to do something like that?

Authenticating AD user automatically and manually - WebAPI 2 server and SPA client

I'm developing an Enterprise/Internet Application with WebAPI 2 RESTful server and SPA web client (Angular2) —So I have two separated projects created using ASP.NET 4.6 Empty template and both use OWIN and are IIS hosted.
The requirement for Authentication is:
Active Directory user which is logged in to the workstation will authenticated automatically once she opens any page from app in the browser if user id/name found in the database, with no need to enter her user/pass. Let name this as auto-login. Else if it's not found in the DB it will redirected to the login page.
Also there should be a logout option which redirects user to the login page after logging she out.
In the login page any AD user can enter her/his AD user&pass and after successful check against database (existed) and AD (valid credential) she/he will logged in to the system (Obviously it may be different than user currently is logged in to the workstation)
In addition to the web client it will have other clients such mobile apps which will connect and be served by the WebAPI back-end. Users will login there using their AD user & pass too. Let name it manual-login.
According to the REST architecture and having both AD enterprise and internet/mobile users together, the authentication should be token based —this is what I found till now but I'm not sure.
I read about OWIN Authentication architecture and Windows Authentication and I checked MixedAuth, Now I think it is the nearest solution for this requirement as it lets app-defined users to authenticate side by side of windows/AD users. But even after dig into it and its SPA sample I didn't found my way yet and confused.
Anyone can help?
What should I actually do on the WebApi server and SPA Client to accomplish those authentication requirements?
Which middlewares should I add and how should config/manipulate them?
UseCookieAuthentication ?
UseExternalSignInCookie ?
UseOAuthBearerTokens ?
Can I rely just on Bearer tokens (using OAuthBearerTokens MW) and get same token for authenticated windows users to unify authentication model based on bearer tokens? If so, how?
How and where should I put my code for checking that AD user exists in the DB and if not so reject the authentication?
Thanks a lot.

How does SE's single signon work?

Basically I just want to know how does StackExchange's single signon system work?
In the SE network you need to login only once in one of the websites to be automatically logged in to the other sites upon visiting.
How should I implement such a feature in my own network of sites?
I assume it uses the cookie which resides on the user's browser and then authenticates it with the originating site. If it is legit then it logs the user in automatically.
You have to implement SAML or oauth2 to allow sso on your network.
In case of SAML your child websites will be service providers or resource servers.
While you need to setup and identity provider.
The sequence of events will be like this.
1. User hits a url of songs website, this site is resource server and does not handle authentication.
2.To authenticate resource server will construct a SAML authrequest and redirects to identity provider after signing it.
Idp verifies the signature after receiving authrequest.
3. User will be presented with a login form, user has to end login credentials.
4. After user authentication idp will generate a SAMl token and redirect back to resource server.
5. Resource server will extract identity information from SAML token, resource server will login the user with session or cookie.
Depends upon which technology you are working in i have implemented it in php using simplesamlphp.