I am trying to prevent multiple concurrent sessions for a user using ASP.NET Core and CookieAuthentication middleware.
Any tips on how to do this?
Ideally, once a user signs in, the app would invalidate and effectively "sign out" all other existing cookies issued for that user. Then, the old sessions would be redirected to the sign in page on the next interaction with the server. So far, I have not found a way to do this.
I have been trying to figure out a way to use a custom validator as described in the documentation.
Thanks!
This is how I've handled it (using ASP.NET Core, but that is irrelevant): To do this you need to maintain state somewhere that is accessible to your server(s). You can store a session ID in a database when the user logs in. Each web app client should hit a heartbeat url (e.g., every few minutes). The back end for the heartbeat checks the session id in the database. If it is the active one for the user, then all is good; otherwise it clears the cookie. If you are using a persistent connection to the client (websocket) then you can push a message to the client to indicate the session is no longer valid.
If you need to be sure that no other action by the user's other session can take place once a new session has started, then you'll need to check the session (as described above) on every call. ASP.NET Core's middleware capability is perfect for this.
Related
I'm working on a .net Core 5.0 MVC project that the user logs in using Windows Authentication.
So there is no Login controller. The browser itself asks for username and password and redirects the user to my controllers.
And I want to do some logging right after the user logs in. I want to log to the database some information regarding the User + Date + IP.
If I understood correctly, if I use .net core middleware (if I create my own middleware and place on Startup.cs), I will be logging on every request. And that's not what I want. I want just the first login of each user.
Is there a way to do that? I've tried to search SO and MS docs, but couldn't find an answer.
Is there any interceptor that happens only after Windows Auth login?
Thanks!
The only way I can think of doing this is by hanging off something you store somewhere. There isn't anything out of the box that I can think of.
A cookie would work but is too volatile. The only safe and consistent way I can think of is to hang off a value stored somewhere in your user store (database) that is a booleon flag that once you have done your first login stuff, you set to true and can check on subsequent requests.
Much like you are probably doing with email confirmation if you are using the standard ASP.NET Identity and demanding verified email addresses.
I've an AspnetCore + Angular setup where the authentication part is handled by IdentityServer4. One of the requirements now is to get a list of all users who are currently logged in. Any ideas/suggestions how to proceed on this?
PS: Just in case it's needed, I'm using implicit flow .
Auth is persisted via a cookie, which lives client-side. The server doesn't know who all is logged in. It only know in the context of a particular request (where the client sends the auth cookie back) whether that particular client is authenticated or not.
If you really need this, you'll need to manually track it yourself somehow, like adding a record to a table for each login. However, this can get gnarly fast. You'll need to also manage sign outs and expirations, to keep your custom data fresh.
A generic answer could be: ASP.NET CORE keeps each user session in a cookie, separately located at each user's browser on each device. Once you need, you have to centralize that system yourself. Howerwer, since the question regards Identityserver, we can look into what is already done in that area by the IdentityServer authors. And they have provided at least two extensibility points.
The first one is to employ Reference Token (instead of the jwt by default), then look through the persisted grants database, fetch all the sessions grouped by userId. Not a standard way for OpenIdConnect, but it exists.
The other approach is to implement your custom session store based on a database (instead of the cookie based by default). That provides you access to all the clients logged in with the given user id. Here is my old (but still valid) example of a hybrid (cookie + IDistributedCache such as REDIS) extension for the DefaultUserSession. Usually after the requirement to list all the user sessions, appears the other one: to create a kill the session button next to each row. Here you have to be careful with access token lifetime (make it reasonably short), as a jwt once issued can not be invalidated before its normal expiration.
There is provision in the default cookie provider in ASP.Net Core to use a DB or distributed cache to store cookie payloads. Check out the Microsoft.AspNetCore.Authentication.Cookies.ITicketStore interface and the CookieAuthenticationOptions.SessionStore property.
We created our own implementation that stores auth cookies in the PersistedGrants table along with IDS4 stuff. It works well, keeps cookies small and facilitates a "sign out on all devices" option also. If you align the expiry of the entry with the cookie authentication properties then the housekeeping is done for you.
I currently have a .net core application that uses Identity Server 4 to authenticate users. We have two different applications; an MVC portion of our site that users can login to, and a SPA that users have to login to as well. Is it possible to make it so that anytime the user logs out of one of those areas, that it logs out of both?
This is the main idea of Single Sign-On. Not only single login, but also single logout. Identity Server 4 fully support this, but you just need to configure both your clients (the MVC app and SPA) with their proper configurations. This is the official documentation about signing out. It works.
EDIT
PS: Have in mind that Identity Server does not invalidate the access token, once you are logged out. In other words - if you, by any chance, still have the access token, you will be able to use it, as long as it is valid (its validity period has not expired). This is why usually the access token is set to have a shorter lifetime.
There are 2 front channel ways to acheive this and I'd recommend using both.
1) Front channel log out which uses an endpoint registered against each client. When you sign out of IDS4 (assuming it's implemented properly) it will make a request to the registered endpoint for each app that was signed into during the current session. http://openid.net/specs/openid-connect-frontchannel-1_0.html
2) The session monitoring spec which uses a bit of javascript and cross-domain iframe magic to notify the client app when the user's session changes on the IDP. Using this you can immediately respond to changes and do any cleanup you need to. http://openid.net/specs/openid-connect-session-1_0.html
As mentioned in m3n7alsnak3's answer this will not invalidate any JWT access tokens (you can use the revocation endpoint to revoke refresh or reference tokens however). Therefore I'd recommend having the client applications to the best job they can of clearing up any state they can, i.e. clearing all cookies, session/local storage etc.
My asp.net session objects are storing in SQL server.I am storing an ID in session. If client open another browser and storing different ID in session. I need to notify client is “are you sure you want both ID’s open?” in same based user logged user.
Application runs on logged in user (not anonymous)
How can we check this in asp.net?
Session is not linked to an authenticated user, and there is no way of accessing an other connection's Session without knowing its SessionID.
Usually this kind of problem can be solved using cache instead of session state. With cache you can create your own user-based keys to store data. Depending on whether you are planning to just run your web app on one server or in a web farm environment, you can either use asp.net in-process cache or one of numerous distributed cache solutions (like memcached which I'm using in my web projects with great success).
There are a couple ways to go about this:
Option #1, in your user table, add a value called "session id"
When a user logs in, check to see what their last session id was. Then test to see if it's still a valid session. If it is, ask them what they want to do. Store the latest session id in that table after each log in.
However, I'd go with option #2: Don't do this. If the user wants to open multiple browser windows to access your application then let them. There's probably a pretty good reason for it. Most (as in nearly all) users have no idea what "session state" even means and they really have no desire to know. All they care about is getting their job done.
I was wondering if anybody could give advice on a secure way to implement a global login. I have an admin page that accesses active directory admin groups after typing in your username and password.
current logged in account (on computer) does not matter
user in web browser goes to web app, redirects to global login page with query string of app name
types user name and password of an account in AD (not necessarily current computers logged in user)
authenticates (looks up user, pass etc and authentication is valid)
redirects back to original web app.
Once redirection happens, how do I securely tell the original web app that this user is ok until the original web session dies?
The way I'm thinking of implementing it:
My original thought was to pass the session ID of original app to the login page as well as the app
name. Store that session in a DB once authentication is checked. Master page of the other app validates on page load that the session ID matches. On session close, remove current session ID from DB.
You cannot depend on sessionID accurately in some cases. SessionID only becomes a constant value after a (any) page makes a request for a session variable, if you dont have Session_Start not defined in global.asax. If you log the user in and the default page does not access session, you will end up with a different session id for the subsequent requests until a request to session is made. Usually it is always constant as there is a default empty session_start event in global.asax.
But similar to your model, you could generate a GUID (or make sure you access session on login/authentication) and store it in the user table with an expiration. Your web sites can check this key and if currently valid, auto sign the user in.
You also cannot depend on session_end event since there is no real accurate way of detecting it (eg: user closing browser). So, you should store this ID with an expiration time along with it, preferably the same as session timeout. Just like session, you will need to extend this, something like a sliding expiration. This way, this id will be expired after a period of inactivity.
also, this Claims-Based Single Sign-On for the Web may be of interest to you.
What you're describing sounds like it would be better implemented using Windows Identity Foundation and Active Directory Federation Services 2.0. I don't know the extent of all your requirements, but it might be valuable to check out what these will give you out of the box.
You could use a cookie. If you pass the name of the application to the login page, you can set that application name to the PATH property of the formsauthentication cookie. By setting the PATH property, you're effectively limiting the readability of the cookie to the pages within that path. Because it's a common login interface, this may require some code being done perhaps in a common page base class that handles the parsing of the cookie information.
You can share authentication tokens between .NET applications, even between .NET CLR's if you want to. I think this will give you the single sign on you're looking for.
At a high level you need to share a machine key between the applications. You can generate the machine key using the key generator app code example found on this link, and providing you then reference the same key in each application the sign on can be shared:
http://msdn.microsoft.com/en-us/library/ms998288.aspx
There are some consideration when looking at things across domains or accross machines/web farms etc, but if all apps are on the same box it's not too hard.
The harder side of things is sharing things like session state which I don't believe can be done accross app pools. (I ended up recreating the session object on the new app manually last time I did it :( but that was between 1.1 and 2.0 apps )
EDIT: I did a rough write up of it last year and was using it as a test for a demo article on my site, might be worth a read through if you want things broken down a bit more (Ignore the unfinished site!):
http://www.dougmcdonald.co.uk/test/html5/v5/articles/2010/05/10/Sharing-forms-authentication-between-applications/