I have an ASP.NET application that uses a custom MembershipProvider to allow users to log in and gain access to certain features. The MembershipProvider uses ASP.NET's built-in forms authentication to set cookies and keep track of who the user is.
Now that I've got the user logged in, what's the best way to store user-specific information for their session? In the past I've just used Session variables ie Session["ReputationLevel"] = "4230"; (my application doesn't actually have a reputation level variable, this is just an example). Is this still the best way when using a MembershipProvider? Would it be better to somehow build this information into the provider itself, or into a custom MembershipUser implementation? If I keep everything in the session, I suppose I'd have to abandon the session when the MembershipProvider indicates that the user had logged out...?
Sorry if this question is vague. I've been doing mostly ColdFusion development for the past few years, and I'm still kinda new to some of these ASP.NET technologies. I thought the MembershipProvider functionality would take care of everything I needed, but I'm now seeing there are still some holes in my implementation (in this case, where to store additional data).
This question appears to be similar, but doesn't appear to be quite what I'm asking.
If you want to persist the information beyond the session, it's probably best to store it by user in your database. There are several ways to do this:
You can roll your own by manually storing and reading in data from a SQL table as needed -- possibly using the runtime cache to save from hitting the db on every request.
You can extend MemberShipUser in your custom membership provider and add the properties to it. Here is a walkthrough...
You can use ASP.NET Profiles, which might be the easiest way to go and it supports storing data for unique unauthenticated users as well. Here's a walkthrough for profiles, although there are several more out there.
I'm not sure how you would do it, but I suppose you could extend the Membership provider to do that. But personally, I've found that ordinary sessions work just fine. Only thing I'd do is to wrap their functionality in a a set of shared functions. So your example would be:
static string GetUserReputation()
{
return Session["Reputation"].ToString();
}
and just call GetUserReputation
Related
Hey folks, I would like to know is there any way i can maintain stuffs like log-in,log-out,user-session..etc without using membership in ASP.NET MVC?
Faraaz.
There are three provider models concerned with the areas that you are referring to.
The MembershipProvider is concerned with authentication, validating users and storing data related to the user such as last login date, username, etc.
The RoleProvider is concerned with authorising users for particular areas of your application.
The SessionStateProvider is concerned with storing session for your application.
You can write your own custom provider for any of them if the default providers are not suitable. You could roll your own authentication, authorisation, or session management without the providers, however there would be quite a bit of work involved more so than implementing your own custom provider.
You can use the Session object to store session scoped data.
But for authentication/authorization you will need to come up with your own scheme.
You need to use the Session dictionary and a session state server. See http://msdn.microsoft.com/en-us/library/ms178581.aspx for more info.
Word of warning: In my experience the InProc session state mode only preserves the values you put into Session for the lifetime of the current HTTP request. They don't persist across requests as you might expect, even when you're using a single HTTP server and you'd think in-memory storage would persist. This may only occur while debugging using the built-in http server in VS2010, but even so it can cause you a lot of trouble trying to understand why state information isn't being saved.
When a use is logged in (Through open-id) we are creating a session variable named "UID" and storing the unique user-id in it. Later we are checking the session to see if the user is logged in. I think this is not the right way, but I could not force the team to change this, as I cannot show how this implementation can be cracked. Can anybody show me why (If yes) this implementation is bad?
I can see no situation where you should worry about a server-side Session value being obtained through a client-side exploit. There has been some concern about fake OpenID providers tricking users into passing credentials because of the lack of stature to OpenID, but generally it's unwarranted.
The implementation seems acceptable, but given that you are using ASP.NET you should consider using IIdentity and this ASP.NET OpenID provider:
http://code.google.com/p/dotnetopenid/
It's well tested and has quite a bit of security code and API support built into it.
My first question would be, what is making you think this is not the right way?
Storing data in this way is very common, secure and it's localized specifically to a user. If you don't like using the session for other reasons such as handling sessions over multiple servers or having to serialize / deserialize the session to a data store (assuming non-memory session) then that is a different arguement but the security part shouldn't be the issue.
Also keep in mind the simplicty of using the session as well. It makes data access to user specific data that you need to access constantly, standard and consistent throughout your application.
EDIT based on comments:
I was wondering the same thing when I started using MVC as well and it seems to be totally fine. I couldn't find anything against the idea. I even asked this question because my custom authorize attribute had to access the session and I stored special role types in it that the out of the box authorization didn't quite fit.
As Nissan Fan stated, I can see no reason you should be fearful of a server-side session value being exploited.
Just out of curiosity, what are some of your reasons for thinking it's not the right way to go?
I've been researching this intensely for the past few days.
We're developing an ASP.Net MVC site that needs to support 100,000+ users. We'd like to keep it fast, scalable, and simple. We have our own SQL database tables for user and user_role, etc. We are not using server controls.
Given that there are no server controls, and a custom membershipProvider would need to be created, where is there any benefit left to use ASP.Net Auth/Membership?
The other alternative would seem to be to create custom code to drop a UniqueID CustomerID in a cookie and authenticate with that. Or, if we're paranoid about sniffers, we could encrypt the cookie as well.
Is there any real benefit in this scenario (MVC and customer data is in our own tables) to using the ASP.Net auth/membership framework, or is the fully custom solution a viable route?
Update: I found one person (Matt Briggs) who seems to have come to some of the same conclusions I have: This comes from this link: http://webcache.googleusercontent.com/search?q=cache:Xm1-OrRCZXIJ:mattcode.net/posts/asp-net-membership-sucks+asp.net+membership+sucks&hl=en&gl=us&strip=1
ASP.net membership is a poorly
engineered API that is insecure out of
the box, is not well maintained, and
gives developers a false sense of
security. Authentication is a weekend
project if you aren't building a
framework, but still, most .net
developers blindly follow the official
APIs, assuming that a major
corporation like MS can put out
something decent.
One of the first rules of creating a secure authentication system is that you shouldn't try to build the framework yourself. There are many pitfalls that can be easily overlooked. So, I would say unless there is an overwhelming reason to do otherwise, you should use an existing framework like the MembershipProvider.
To list "the benefits" requires listing all security measures that were taken by the FormsAuthentication classes which is a long list. Off the top of my head, I can think a few:
Hashes of passwords
Protection against SQL injection
Protection of the cookie that stores the authentication ticket
Use of and storage of a ticket instead of say a username in the cookie.
Checking on every page to ensure the user is authenticated
Population of the IPrincipal and IIdentity for the current user
Redirection after login (granted a feature)
Handling of failed login attempts
Locking and unlocking users
ActiveDirectory integration
Ability to easily set and change password length and complexity requirements.
Salting (from Hightechrider)
....
I wrote my own after reading through all the stored procedures in the ASP.NET Membership provider. It's not hard and you have much more control at the end of the day.
If you like XML configuration, weakly-typed strings for roles, insecure by default, random web.config files littered through your directories instead of a clean marker interface on your page classes to say 'no account required', multiple database hits for a single login, user objects that aren't loaded from your current ObjectContext/DataContext and the ability to change providers on the fly (woo hoo, who uses that?!) go for the built-in one.
If not, build your own, but if you do, make sure you add salt and encrypt your passwords, and do a proper encrypted cookie please.
Just to clear up a potential misconception, using the customer ID, encrypted or not is extremely vulnerable to sniffers. What you want to do instead is create a log in ticket at the time of successful authentication and store that ID in the cookie. This won't protect sniffers from stealing sessions, but at least the session (eventually) expires whereas the customer ID does not.
You can implement your own membership provider (as you mentioned) if you wish to have your own storage. One advantage is that you can administer memberships through IIS' .NET users configuration tool.
The biggest advantage is what the others stated already; why reinvent the wheel?
If you implement your own custom login UI using MVC you could reuse also when switching for a different membership provider.
You can customize to build your own provider. Behind the scenes the Membership provider uses the same FormsAuthentication implementation as you will write. Anyway, I have read that the main issues about the performance you will face will be related to the SQL SERVER stored procedures that retrieve the data. In one of the books about building a portal system by Omar Al Zabir he mentions some improvements to the stored procedure which can result in faster performance.
I'm porting an ASP.NET application to MVC and need to store two items relating to an authenitcated user: a list of roles and a list of visible item IDs, to determine what the user can or cannot see.
We've used WSE with a web service in the past and this made things unbelievably complex and impossible to debug properly. Now we're ditching the web service I was looking foward to drastically simplifying the solution simply to store these things in the session. A colleague suggested using the roles and membership providers but on looking into this I've found a number of problems:
a) It suffers from similar but different problems to WSE in that it has to be used in a very constrained way maing it tricky even to write tests;
b) The only caching option for the RolesProvider is based on cookies which we've rejected on security grounds;
c) It introduces no end of complications and extra unwanted baggage;
All we want to do, in a nutshell, is store two string variables in a user's session or something equivalent in a secure way and refer to them when we need to. What seems to be a ten minute job has so far taken several days of investigation and to compound the problem we have now discovered that session IDs can apparently be faked, see
http://blogs.sans.org/appsecstreetfighter/2009/06/14/session-attacks-and-aspnet-part-1/
I'm left thinking there is no easy way to do this very simple job, but I find that impossible to believe.
Could anyone:
a) provide simple information on how to make ASP.NET MVC sessions secure as I always believed they were?
b) suggest another simple way to store these two string variables for a logged in user's roles etc. without having to replace one complex nightmare with another as described above?
Thank you.
Storing the user's role information in a server-side session is safe providing a session cannot be hijacked. Restating this more broadly, it does not matter where user role info is stored if an authenticated session is hijacked.
I advise not putting too much faith in the article you linked to, but the 2002 vintage report linked to from your link is of interest. Here are my take-aways:
Don't accept session IDs embedded in URLs.
Focus your time on eliminating cross site scripting dangers i.e. scan all user supplied data and parse out executable java script.
Issue cookies for complete domains (e.g. myapp.mydomain.com)
Host your domain at a high class DNS operator e.g. one that only allows DNS changes from a preset remote IP address.
Don't issue persistent session cookies.
Reissue a session cookie if someone arrives at a login page with a sessionID already associated with an authenticated session.
Better still, always issue a new session cookie on successful authentication and abandon the prior session. (Can this be configured in IIS?)
The only way to make a secure cinnection is to use SSL. Anything less than that, and you simply have to make the evaluation when it's "safe enough".
A session variable works fine for storing a value, with the exception that the web server may be recycled now and then, which will cause the session to be lost. When that happens you would have to re-authenticate the user and set the session variable again.
The session variable itself is completely safe in the sense that it never leaves the server unless you specifically copy it to a response.
Have you considered setting up a custom Authorize tag in MVC. I gave an example of this in another question.
On initial authorization (sign-in screen or session start) you could seed a session value with the IP address also. Then in your custom authorization, you could also verify that IP's still match up as well. This will help make sure that someone isn't 'stealing' the person's session. Everytime you access your session data just make sure to pass the requester's IP and have some check on it.
Are you trying to control the access to functions at the client level? That is the only reason I would expose the roles and items to control client side functions.
Alternatively, you could create a function to obtain the items that the roles of the user are allowed to use, and then even if the function is called outside of the items given back to the web application, you can prevent the user from accessing them.
4Guys seems to show how to control functions with the roles.
The approach I have used in the past is to use symmetric encryption of a cookie alongside SSL. Encrypt the user information in the reponse and decrypt it in the request. I'm not claiming this is foolproof or 100% secure and I wouldn't want to do this on a banking application, but it is good enough for many purposes.
The main issue with session variables is that if you store them inProc rather than persisting them, then you need to apply 'sticky' sessions to your load balancing in a web farm environment. Guffa is correct that without this persistence session variables will occasionally be lost causing a poor user experience.
Sticky sessions can lead to uneven load balancing, perhaps reducing the value of being able to scale out.
If you are going to be be persisting the sessions so they can be accessed by all servers in your web farm, you may be better off using a Guid to identify the user, encrypting this in a cookie and retrieving the user record from your data store each time.
My obvious question is that why do you want to store a users role in session ?
Here is my answer to your query, how this helps. I have attached a small demo application for you to take a look at and understand my points. When you open this project in visual studio, click on the project tab on the top and select asp.net configuration. From the page that will show up you can do the user administration stuff.
You need to store the roles of a user in some secure manner ? The answer to this question is that there is no need for you to worry about storing the role for any user, when we have the asp.net membership, profiles and roles framework to help us out on this. All you need to do is create a role in the aspnet database and assign that role to the user.
Next you want to store two string in some secure manner. I suggest you user profile for storing user specific information. This way you have the information available to you where ever you want from the profilecommon class.
Also please see the attached demo application placed at the end of my blog http://blogs.bootcampedu.com/blog/post/Reply-to-httpstackoverflowcomquestions1672007user-roles-why-not-store-in-session.aspx
Just a suggestion, you might consider using this little library:
http://www.codeproject.com/KB/aspnet/Univar.aspx
It has a server side implementation of the cookie whereby all cookies can be stored on the server while asp.net authentification is used to identify the user. It supports encryption and is also very flexible making it very easy to switch from one storage type to another.
I am trying to achieve anonymous personalization in a ASP.net environment. I know that ASP.NET 2.0 provide Profile. However, I want to avoid traffic to the database as much as possible since the site I am working on is a relatively high traffic site.
The other obvious solution is cookie, but given the limitation of cookie, I was wondering if anyone have any efficient method to store information into cookie. Does anyone know how amazon or yahoo deals anon. personalization?
Ultimately, We are trying to serve up different dynamic content to our user base on a set of business rules outline in a pre-defined campaign. The reason is to measure conversion rate in our site. The same campaign can be use on all different pages of the site. The reason I need to set this to a cookie is that the user is able to see the same content served up previously if we want it to be. So this is what I have in cookie right now.
campaign code:page id:result display
And you can see that this will build up if there is a lot of campaign and each campaign is used on many pages.
Thanks in advance!
If database load is an issue, you can retrieve the personalization when the user starts his session on the website, and then store it on the session state. This way, only the first page load will make a call to the database.
You can store the user ID in the cookie.
Just remember to persist the session in the db when the user updates his preferences, and deleting old db records after a while might be a good idea too if that many anonymous users will visit your website.
If you want to persist the changes, such as each campaign view, there really isn't any way around accessing to write those changes. ASP.NET Membership is not bad on a high-volume site (>1 mil a day), when used correctly. For instance, you should be wrapping calls to the membership provider in a cached object, and refresh often (short expiration). Also, make sure to set the cacheRefreshInterval on the RoleProvider. This will force asp.net to cache the Roles in a cookie, to cut down on DB activity.
Another way to look at this is to take Ady's advice and to seperate the Membership into a separate DB. Yet again, another great feature of the ASP.NET Membership provider - you can set a different SQL connection string, and load it up on a different DB and/or server.
There are several other techniques around the membership provider that can really increase performance. Some quick google searches comes up a number of them.
I'd create a database record for the visitor and only store the ID in the cookie, this way you can look up all the personalised details from the database, and keep the cookie size to a minimum.
If database speed is an issue, perhaps use a differrent database and server to store the personalisations.
Alternativly you could store personal data in the file system, and load into the session when the visitor returns matching the cookie ID.
If identifying the user and cookie clearing is an issue, you cold use and ActiveX control, but this requires installation on the client computer, which people could object to.