ASP.NET Single Sign On - c#

We have two servers that run on the same machine under the same domain.
Both written in ASP.NET and uses the Identity framework.
I need to implement Single Sign-On (and single sign out) between them.
Actual sign-in is done in AJAX (I POST the username and password, the server authenticate the user and sets the session, then sends the redirect data URL to the client).
I found overwhelming amount of information about OWIN, the Identity framework, Claims, etc.
I found tutorials explaining how to create projects using just about any modal dialog and any Wizard there is in Visual Studio, which I tried to understand but really is useless to me, as I already have authentication system up and running.
I even found some demos claiming to implement SSO in all kinds of ways, and some Stackoverflow questions that said to simply put this and that values in the web.config and you're done, which seemed strange to me and I figured out I'm missing some basic understanding of how it works.
Still, I can't understand how SSO works in ASP.NET Identity.
Can someone please explain it to me in a simple manner, or refer me to some kind of such explanation?
Again: I have two authentication systems up and running. What code and/or configuration changes I need to make to get Single Sign-On working?

First, if you want them to share authentication, they need to be working on the same user store. In other words, you should factor out the Identity initialization code (ApplicationUser, ApplicationDbContext, ApplicationUserManager, and ApplicationSignInManager) into a class library that both applications share. Trying to mantain and share two separate databases with user data is going to be an impossible and insurmountable task.
Then, you need only ensure that both applications utilize the same machine key. The auth cookie is encrypted, and since the encryption is based on the machine key, both applications need to use the same key to encrypt/decrypt that cookie.
Since you've already stated that they will both be hosted on the same domain, that's all there is to it.

Related

How to get one login page for multiple systems?

I have four systems running on the same server. I want to let the users to log in once for all the systems. I made one user-management system to create users and edit them.
I tried to save in the session but it didn't help.
Any suggestions? I am working on asp.net.
There are two approaches.
Most resolve around the login happening at a central site, which then returns with an identity information field (login token) that the target site uses to retreive the user.
When you go to another site, the site redirects you shortly to the central site and if you are logged in (persistent cookie) you get back the identity of you.
Alternatively you can do a lot with referrers and playing around.
YOu want to do some research on the internet - what you loo kfo is "Single Sign On".
http://www.codeproject.com/Articles/27576/Single-Sign-on-in-ASP-NET-and-Other-Platforms
has some technical discussions.
Across complete separate websites (domains) you can read up on
http://aspalliance.com/1513_Cross_Site_Authentication_and_Data_Transfer
howw to do it - obviously shared cookies will not work there.
The best way to do this is with Federated Security. If you were using Windows Authentication then you could use Active Directory Federation Services (ADFS). In this model, users reference a Web application and the principal on the current thread is checked. If the value is null then information stored in the web.config will redirect the request to a login page automatically. This is assuming there is no a Windows security context, otherwise the user can be automatically logged in.
After the user is successfully logged into the environment, the principal on the thread is populated and a set of claims are issued that are specific for that user. Since the claims are associated with the principal and not with a specific application, they can be used across the board by any claims aware application.
If you aren't using Windows Authentication, you can still accomplish the same thing, the only problem is that you cannot use ADFS. Instead, you'll have to implement your own Identity Provider to replace ADFS. The .NET Framework does provide base classes and interfaces to help you accomplish that.
I would suggest looking into ActiveDirectory or any LDAP server for single signon to access all applications. If you cannot (or do not wish to) use LDAP, you could implement similar functionality (but with more development work/time spent) with any memory/disk store. If this is not possible, please share why as it might be useful to others.
Hope this helps.

C# 4 ASP.net *NON MVC* Custom Authentication

I know this question as been asked countless times, but believe me I've searched Google for hours and got nothing. Whatever is out there, it's for MVC, which I'm not using.
My requirement is simple. I do not want to use the default authentication provided in asp.net. I would store the username/password/role in my custom SQL Server table. I'll provide 2 inputs for username/password and a button to validate. On validation, he is allowed access to the admin areas. This will only be used by admin guys at my subdomain "admin.*.com". They will use this page to add content to the website on daily basis.
How do I implement it. A tutorial link would suffice.
Is it safe for Production? I don't want some newbie hacker getting in to my site and mess it up. If not safe, what else option do I have.
Thanks,
Dev
As per our comments, given your reluctance to implement an ASP.Net Membership provider (and it is worth the time to investigate - you may not feel that it is right now, but it can be handy. I felt the same way at first, but the cost of maintaining your own code and infrastructure soon proves to be false economy) you have at least two other choices:
1) Straightforward Forms Authentication
Put all of your admin pages under a single folder, for example, /Admin, then use Forms Authentication to protect access to this folder. Only users defined in the database or Web.Config will have access to these pages. This is less flexible than ASP.Net membership, but may give you most of what you want. In terms of security, this will be as secure as your website is, is well tested, and is well documented.
2) Use Facebook OAuth
You mentioned that your use has access to Facebook. You could use Facebook to do the authentication for you. Although you wont be able to grab the username and password, you can get a token back, that you can then validate against a known permission set. This is a lot more work than 1) though and will tie you to potential future changes in the Facebook API. However, it also benefits from being well tested, and secure, but you have little to no control over the actual user information.
As an aside, please also consider being nicer to Google!
You can create your own custom membership provider which has the features you are looking for.asp.net membership provider
Its best to use the tried and tested method for security purposes. Remember you can customise any providers including role providers or even create your own unique providers.
Here is an example how to LDAP authentication using ASP.NET 1.1. The logic may still be applicable or can be adapted to later versions of ASP.NET, although I have not tested it.
Using the built-in membership providers, or implementing your own, is no guarantee that a hacker can't get access to your system. Things you'll have to consider:
encrypting data between client and server
don't store passwords in the database, not even encrypted. Hash each password its own salt, if you can.
enforce strong password entropy.
make sure session and authorization cookies are marked HttpOnly and Secure
for admin passwords, have a policy to change them frequently (like once a month)
provide means to notify administrators when someone signs in to their accounts
temporarily lock out ip address who exceeds number of requests per second and failed to authenticate
temporarily lock out users when they enter their password more then x (e.g. 10) number of times in an y number of minutes (e.g. 10).
These are just a handful of things to look for. You'll also have to concern yourself with session highjacking, javascript attacks and so forth.
Its not a trivial matter.
Writing a custom authentication handler is very dangerous. There are many ways to get it wrong and leave your website vulnerable to attack.
I also understand your complaint that Forms Authentication is extremely complicated. I was faced at a similar cross roads and decided to build my own authentication system called FSCAuth. It's BSD licensed. It's designed to be super simple and to allow for just about any database format you can image. All that must be done to set it up is implement a small 4 function interface into your database and populate a few configuration fields.

Best way to handle WCF message authentication in the cloud (C#)

I've looked to many sources, and found many examples, but none really fit the situation that I hope to take a project to. I am writing a bunch of WCF services, some publicly accessible, others not (server to server), that will allow a fully flexible cloud app that ensures the ability to scale out the service as needed through Azure. I am unsure which way to go with message authentication, as I want to make sure a particular user logged in, can perform different tasks, and prevent others from running those tasks.
Most of what I have seen uses roles or ASP.NET membership. I have my own custom membership users will use to login with, and I don't rely on standard membership providers, or active directory. What is your recommendation? I thought about just creating a token that is created on successful login, that is stored within a cookie, added as a parameter passed into each method, but with some research, I think this might be able to be handled without modifying all my methods.
What are your thoughts?
You can easily implement authentication without needing to manually pass a token into all your functions by using UserNameAuthentication and writing a custom validator - there is a fairly straightforward tutorial here
If you use UserNameAuthentication, you will need to use SSL/HTTPS, which means you'll need to get a server certificate - this is a good idea anyway for most business applications.
At the server side you can get the identity of the current user:
IIdentity wic = OperationContext.Current.ServiceSecurityContext.PrimaryIdentity as IIdentity;
use basic authentication and have the webservice authenticate against your membership store.

Shared User Session for Multiple ASP.NET Websites

I have been tasked with developing a single Login and Dashboard page that user can login too, the user will then be shown all the systems (we developed) that they have access based to based on some roles stored in our databases.
If they logged in we would like that "User Session" (not sure of correct terminology) to be carried to which ever system they are redirected too.
To illustrate a very rough overview of what I want to achieve:
alt text http://www.pcbg.co.za/attachment.php?attachmentid=12165&d=1268903524
Is there a way that a user can login in one site, and then carry over that login to the other sites?
Help, Advice, Link will be much appreciated.
Sorry I am not experienced at ASP.net but have a good understanding of Silverlight, C#, WPF.
Thanks in advance.
You can use the concepts of single-sign on. You can manage your session data as out-proc, i.e. in a SQL server or a State server. Here are couple of links which will give you some pointers:
ASP Allaince
MSDN
Edit: Alo look at this question in SO:
One method that I would use is that you implement your own authentication system - almost like the ASP.NET 1.x days. However, the trick is that you establish a cookie for each domain (host part of the URL) with an authentication cookie.
If all of those systems are running on the same server, I am sure you will be able to use all the FormsAuthentication methods and the Membership API. If they are not [edit: hosted on the same server], then ensure that they configured to encrypt the authentication cookies with the same keys. Implementation of this bit will be by what mileage you need to do...
One thing to notice is that you may also establish only one cookie is sent to the browser but shared by all the applications. Imagine that you have the following URL's:
dashboard.com
myapp1.dashboard.com
myapp2.dashboard.com
myapp3.dashboard.com
Setting a single cookie to the domain "dashboard.com" will send and share the same cookie to all the other domains.
The shared session states as described by the other posters will not work. The way session variables work on the server is that an unique key is generated on the server for your data storage (whatever the medium is: in proc, out of proc, SQL server). That unique key is stored in a cookie where it is sent to your browser as the host part.
I hope that gives you some insight on how to go about tackling the single sign in solution that you are making.
One way would be to use the session state service that ASP.NET provides. Basically once the user logs in, that session could be stored on a separate process (and not be a part of aspnet_wp). All your applications would need to be modified to go to that machine to fetch user authentication status. Search Google/MSDN for Session Management techniques.

How to allow multiple authentication methods in ASP.NET?

I'm building a new ASP.NET MVC application (in C#) and one of the requirements is to create a new database of members. For this, we'd need roles to manage the different types of members and profiles to manage the additional metadata attached to each member. So far so good, just use the standard MembershipProvider, RoleProvider and ProfileProvider provided as part of the .NET Framework.
However, the catch is that I'd like to allow different authentication methods. I'd like Accounts and Login Credentials to have a one-to-many relationship (one account can have a number of login credentials attached). A user for example, might have both an OpenID and ActiveDirectory account attached to their account.
However, after experimenting with a few ways we opted for the MembershipProvider route (explained how it was achieved as an answer below).
My question is, how have people done this before and how would people suggest I approach it? It appears to be something that is achieved on quite a number of sites, yet a search on here doesn't return anything solid to play around with.
EDIT: After looking around for a good period of hours overnight and this morning - I'm still not convincinced that butchering a single MembershipProvider would have been the easiest option. Does having multiple MembershipProviders give the same effect?
BOUNTY EDIT: With no responses, I am assuming that there is no more optimal solution that the one I posted as an answer. Is this really the case? I'm offering a bounty to try and see if anyone has any further thoughts on this and whether there are better alternatives.
BOUNTY ACCEPT EDIT: I think that WIF is the answer as accepted below, for a .NET 4 release and maybe other versions as it probably works with 3.5. Other than that, maybe a butchered MembershipProvider or adapted one may still be relevant.
In my opinion, the "real way" of doing this is to use federation with WIF (Windows Identity Foundation, formerly Geneva framework).
The idea is that you separate authentication from authorization. The authentication is performed by a so-called STS (Security Token Service) and it manages all the possible login mechanism that you want to support. When a user has been authenticated the STS issues a token containing a set of claims and the user's identity.
This token is sent to the web site (called a relying party in this lingo), and the website determines which parts of the site the user has access to based on the claims in the token. WIF supplies both membership and role providers that extract information from token.
You can read about creating a claims aware website here.
One of the pros of this approach is the separation of concerns between authentication and authorization. You do not need any complex membership and roleproviders in your website. Furthermore the STS can be reused to authenticate users to other applications you might have without them having to register more than once (effectively achieving single sign-on)
The downside is that you will have to spend some time studying these concepts and coding your STS. Mind you, it is not hard to code an STS with WIF, but it is not a 100% trivial task either.
If I have managed to tickle your interest I would recommend that you start out by reading this whitepaper.
Kind regards,
Klaus
One idea we've followed is to create a custom Membership / Role / Profile provider. We customised the login / authentication methods significantly and have an additional table of logins. This table basically just contained:
LoginID (Auto-Incremental ID, PK)
UserID (FK)
LoginSystemID (FK)
...blah blah
Within the above, the LoginSystemID was a link to a foreign lookup table which helped the system to determine which authentication service to use (e.g. Standard, AD, OpenID, FacebookConnect - etc).
The problem we ran into was that the Username field in the MembershipProvider couldn't be empty and while in our schema everyone had a UserID (it was their account name), they didn't have a Username that was unique. We had to get around this by generating a GUID and using that. This of course is hidden from the user and a DisplayName attribute from our Users table can be displayed instead.
This was all done via FormsAuthenication (the AD checks were done via LDAP checks). However, an additional layer (a webform) was added with appropriate settings within IIS that provided a means for automatic WindowsAuthentication - we redirect to there in the instance that we feel the user is likely to be internal (based on IP address).
Use standard framework stuff. See http://blogs.teamb.com/craigstuntz/2009/09/09/38390/
You can have an unlimited number of authentication methods attached to one account, the magic is in the FormsAuthentication.SetAuthCookie(userName, createPersistentCookie); statement

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