I am developing an application that will support several departments in our organization, and want to define what data is accessible by AD Groups a user is in.
My question is, is it more cost effective resource wise (bandwidth, time slices, etc) to use an IsUserInRole() call at each decision point or to load several Session[] variables at user login which are Boolean and use those throughout my code?
Thoughts?
I would avoid Sessions. They make scaling an application harder since you need a centralized store (a Database or Redis), while will be hit at every single request. It slows down the process since you have to wait for the request to complete before going on with the actual business logic.
The answer for this is using JWT tokens. They work very well for small amount of data (like a limited amount of roles, not hundreds of them). JWT tokens can safely be put inside a cookie so every browser request carry it to the server.
You may get more information about JWT tokens here: https://jwt.io/introduction/. This other StackOverflow question has a lot of information about JWT tokens: Using JWT to implement Authentication on Asp.net web API.
I hope it solves your issues. Good luck.
Related
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.
We are currently starting to use MVC and are now looking at authentication. .net Authentication isn't necessarily our strongest point, so looking for some advise or pointers.
Our current set up:-
Basic Windows authentication
system uses the authenticated user to query a 3rd party system to get their current roles
these roles are then stored in session variables and used when ever authorisation is required
Any additional user details are called upon as and when needed from various tables
What we'd like to achieve :-
Basic Windows authentication (perhaps create a forms authentication cookie on the back of it)
System users the authenticated user to query 3rd party system to get their current role/s,
These roles are stored within the cookie, and can be accessed via User.Roles etc
Any additional user details (i.e. user favourite colour) will be called on authentication and store against the user profile. The additional user details will be stored in a single table as key value pairs.
Is this the correct way to go about this? we're struggling to find any samples etc to match the scenario we are after.
unfortunately, we need to use this 3rd party system to access the roles, this is achieved via a web service call.
Are there any new advances with MVC 4 which could greater handle authentication with additional user details?
any help, or advise would be greatly appreciated. :)
Sounds like a perfect candidate for federated authentication. You could even use WIF (Windows Identity Foundation) which is now part of the Base Class Library.
In general, federated authentication consist of following parts: delegating the authentication to an external identity provider, consuming identity provider's response, persisting the identity locally (in a cookie perhaps).
WIF has solutions for all these concerns, it is built around the WS-Federation protocol. The really, really great benefit of this is that you can switch between different identity providers easily. This is something that you could consider useless, until you see it in action and immediately you start to create complicated business scenarios in your head.
Using WIF requires some knowledge and specific questions can be answered easily. However, until you get at least some basic knowledge, this sounds like a mumbo-jumbo. You should definitely start by reading a free ebook, Claims-Based Identity and Access Control from here
http://msdn.microsoft.com/en-us/library/ff423674.aspx
Just download it and start reading. I promise you'll immediately find answers to many of your questions and page by page you'll feel this constant "wow, so that's how it should be done!".
Just to provide a specific answer to one of your questions: user data can be persisted in the authentication cookie. If you stick with WIF's model of Claims, expressing arbitrary data is natural: a claim is a pair (claim type, claim value). This requires however to switch to SessionAuthenticationModule as forms authentication module could possibly produce cookies that are too large:
http://www.wiktorzychla.com/2012/09/forms-authentication-revisited.html
(the session authentication module has a special "session" mode where the large part of the identity is stored locally at the server in the session container so that the cookie is really small)
And yes, the federated identity model works with MVC authorization tags. Claims of type role are interpreted as user roles. The remote identity provider can then even set user roles and you can guard your MVC controllers in the usual way.
If you are lucky your 3rd party component might bring a Claims provider with it so you could use Claims based authentication and let the Claims provider supply the additional user data in form of Claims that you can use in your application. For a tutorial see this link. If you cannot access a Claims provider, the known security building blocks still work for MVC. So for your additional roles, you could create a RoleProvider that requests the roles and configure it in your application. You can then secure your controllers or actions with the Authorize-attribute.
In order to optimize the request for roles so that you do not have to request it from the 3rd party system over and over again, there are some alternatives:
As you propose in your question, you can store them in the cookie. But be aware that cookies are stored on the client computer and could be tampered with. So if you have a Forms authentication cookie that you can use, you could store it in the UserData of this cookie. This cookie is already encrypted so that users cannot change it easily. As you want to use Windows authentication at least in the first step, you do not have a Forms authentication cookie that you could use. In the context of security, it is always advisable to set up upon a widely used and well tested framework, so I'd not recommend to create a cookie of your own and store the roles there (though it wouldn't be a too daunting task in this specific case to encrypt/sign the cookie data).
You could also store the roles in a Session variable. Downside is that the session times out after a while and you'd have to be prepared for this case. On the other hand, session memory is located on the server so that it is not that easy for users to tamper with (and if they could, you'd have lots of other problems).
Another component you could use is the Cache on the server; though you'd have to be careful not to mix data for various users as it is shared among users, it is also located on the server and provides a more fine grained control on when the data are invalidated. So you could configure a time frame after that any user would be authorized with a new role set in case it was changed.
Your RoleProvider would need to implement the caching technology (Cookie, Session or Cache).
As for your last point regarding the user profiles, I can imagine that the User Profiles of ASP.NET 2.0 still work. I don't have any experience with it, so I can't give you a recommendation on whether to use it or not. On the other hand, these data don't seem to be too security critical so you can also store them in a cookie or session memory once the user has been authenticated.
I've been trying to get my head around SSO in an enterprise environment and what solution best fits my companies problem.
We have several apps (mostly in .net but some in java) running on our domain.. a.mydomain.com, b.mydomain.com etc...
My problem lies in trying to figure out how to implement Single Sign On, because as far as i can see, the likes of OpenID and OpenAuth are used for facebook, twitter, linked in based SSO, ie consumer based SSO.
We want an internal SSO system setup but I cant find many enterprise examples of how to do this and what protocols/frameworks/servers to use.
Can anyone give me an idea how and if OpenID/OpenAuth should be used for this case, and what the benefits and disadvantages are?
also, would token based SSO be a good idea for this? considering all the apps wiill be on the same domain (SSL is setup).
Finally, what about cookie based SSO, is this a good idea?
Thanks
Neil
As you mentioned that all your apps are in the same domain and you are looking for an internal SSO solution I would recommend going for a cookie based SSO service.Simply because
It will be easier to implement. Just checking the cookies and giving the user access to an app.
no XML message exchange between your different apps (no need to design a schema)
You don't need to hire any Web service experts. (As long as your developers know how to handle cookies)
ultimately it will depend on your scalability requirements.
update:
Scalability:
In future you might expand you user-base across different geographic locations.
Your different applications might have different servers and the user database might become distributed.
In such cases you will have to maintain an identity repository to give authentication as a service.(This is what is done by the authentication frameworks that you mentioned)
Cookies:
Cookie handling is no rocket science. The browser automatically sends cookies to
your server in the HTTP request and you just have to read it.
Create the cookie wen user logs in. Set the domain property to your root domain so that
other sub-domains can access it.
Check for cookie when user tries to log into an app. If cookie is present that means the user has already logged in.
Don't forget to delete them when user logs out.
Active Directory Federation Services (http://msdn.microsoft.com/en-us/library/bb897402.aspx) is an enterprise solution. I would not recommend writing your own token issuer as there are lots of risks involved, security and performance.
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.
I've got two programs, a "login" program that uses the a foreign STS (Google, Facebook, etc.) to log the user in and returns the type of security access that user has. I then want to send that information off to a separate program that takes that security access and gives the user privileges based on that.
What is the best way to send that information across?
I've read some things about the Custom Authorization Manager Service, but I'm not sure if that is what I need here. Is it possible to just POST the security info across and the web.config turns that into a claim? Should I be making a new token and sending that?
I am hopelessly lost. If someone could provide a helpful tutorial somewhere on the web, that would be immensely appreciated (as my googling has only turned up long-winded articles that either do much more than I need or much less).
Specific code snippets would make my day.
Thanks!
EDIT: I am trying to avoid making the login system into an STS. But I am starting to feel I need to. Is there some halfway point between STS and relying party? Like a relying party that can generate its own claims?
You have several options:
The simplest one is the ClaimsAuthorizationManager, which might be what you're looking for. http://msdn.microsoft.com/en-us/library/ee748497.aspx The CAM is a step in the ASP.NET authentication pipeline that runs right after your application has validated the security token incoming from ACS. Here is where you define your custom authorization logic, and you can add additional claims to the IClaimsPrincipal that gets delivered to yor application. Instead of centralizing authorization logic in a service, you could for example implement your CAM in a library that's shared accross various relying party applications.
If your authorization rules are simple, i.e., you're not querying any external user attribute store, then one option would be to use ACS claims transformation rules to do this. Then your applications would consume the token issued by ACS directly. http://msdn.microsoft.com/en-us/library/gg185955.aspx
If however your architecture absolutely requires a separate login service that consumes tokens and populates new tokens with user attributes and such, then it will need to be an STS. Building your own STS can be tricky, but there are prefabricated STSes available to do this. If your applications live in an AD domain for example, ADFS 2.0 would be an ideal choice because of it's close integration with AD and ACS, and it's powerful claims transformation capabilities.