Single sign-on for two winforms applications - winforms

There are two different desktop applications, one having oracle as back-end and the other sql server as back end. Both applications have their own User and User Group Maintenance functionality stored in their respective databases. There is a requirement to create single sign-on ,common User group Maintenance functionality and dashboard. How do we handle the login? For single sign-on, I need to have a user/password that somehow needs to translate to the login information needed for respective applications so that users can access the applications off the dashboard. How do I keep the users in sync between the single sign-on, and the other two applications? Could someone please suggest the best solution/approach for this?
I think one way to go would be to have a different sign-on data database and sync it to both db. But the question is where, oracle or sql server? because a client might have access to only one application or both through single sign-on system.

Related

How to restrict data access based on user login

I am a former Lotus Notes/Domino developer, learning the Microsoft stack. I am building a web application with a SQL server back end. I want to build a basic CRUD application where users register, then login. They should be able to work with data they created or that has been shared with them. I am unsure how to achieve that result.
One of the cool features of the Domino database was the ability to add reader and or author fields to each record with user IDs, or roles and the server would automatically filter out those records when a user accesses the database. So if the user opened a View or Queried the database, the server would never let them see records they were not assigned access to.
Does SQL server have similar functionality? I've seen some information on row-level security, is that the best way to secure data? If not, what is the best practice to secure data so users can only see their data?
Thanks for any help you can offer.
Yes. SQL server has Row Level Security:
Row-Level Security enables you to use group membership or execution
context to control access to rows in a database table.
Row-Level Security (RLS) simplifies the design and coding of security
in your application. RLS helps you implement restrictions on data row
access. For example, you can ensure that workers access only those
data rows that are pertinent to their department. Another example is
to restrict customers' data access to only the data relevant to their
company.
The access restriction logic is located in the database tier rather
than away from the data in another application tier. The database
system applies the access restrictions every time that data access is
attempted from any tier. This makes your security system more reliable
and robust by reducing the surface area of your security system.
But it's more common to embed the authorization logic in a server-side application like a web server or web API. Row-Level Security is more common where users connect directly to the database, like in reporting and analytics, and client/server desktop applications.

Which Multi-tenant approach is recommended with SQL Server 2008

I have to use ASP.NET MVC 3 or above and SQL Server 2008. As per Multi-Tenant Data Architecture post, there are 3 ways to implement multi-tenancy
Separate Databases
Shared Database, Separate Schemas
Shared Database, Shared Schema
I have following details:
User should be able to backup and restore their data.
No of tenants : 1000 (approx)
Each tenant might belong to different domain(url).
It must support monitoring and management of tenants.
It must support user authentication and authorization for each tenant
It must support tenant customization(enable disable features set)
No of tables in each tenant: 100 (initial)
I would like to know what your experience says about which approach is more suitable for the project considering Economic and Security? Is there any good real time example(open source project) similar to this? I can use one dedicated server for the project.
Your requirement that users should be able to backup its data, can be achivable more easily with approachs 1 and 2... since it will be a native database task.
If you are in approach 3 (shared-shared), you will need to develop the logic to extract all the rows belonging to a single tenant and export it in a xml file or something like that. Then if you need to allow users to restore that backup file, you need to develop a restore logic.
I think this is the only requirement that could make you move away from #3.
Once you set your database using TenantID columns in your table... you can easily use one database for 1 tenant or a small group of tenants if your client is heavily concerned about security. For instance, you could have one database holding tenants that are not paying (free/demo accounts) and paying customers in another one. This way you are using approach #3, but being able to behave as #1 if you need it.
::: BONUS :::
AUTHENTICATION:
You will need to extend the SQL Membership and Role Providers used in your MVC3 app... so that a user login is valid only in the Tenant it belongs to.
MULTIPLE DOMAINS
Here you can see some approaches using ASP.NET MVC3 Routing:
MVC 3 Subdomain Routing
I would always use (3) Shared Database, Shared Schema.
If you want an example, how about Wordpress, Joomla, or any other popular open source web-based project?
Creating separate schemas or databases on a per-tenant basis will lead to massive management overhead. Not to mention increased complexity of analysing your data, costs, etc.
The only reason you'd go for (1) (or perhaps 2) is if you were to give your actual tenant direct access to some/all of the database. As you're using ASP.NET MVC 3, this isn't a consideration.

Security issues with allowing anonymous users to create SQL Server login and accounts?

I have a rich client program installed on users PCs where I want to start storing some user created data on SQL Azure/SQL Server. The potential anonymous-to-me users would key in their name, email account and a password which would get stored on SQL Azure/SQL Server. Then they would start generating their own data. I'm anticipating volumes of maybe 1000 users.
There are times when those users would like to run their own queries against their own data but, obviously, I must ensure that they can never view other users data.
I'm thinking the best way to ensure security of data is for each user to be issued their own SQL Azure account and password. I will setup a SQL Azure user and long password, known only to me, which only has permissions to execute several stored procedures with appropriate parameters being passed to those SPs which will create the SQL Server accounts, logins and add the users to a role which I have created.
Obviously someone running debugging tools could figure out the user name and password but I'm thinking this isn't a big deal. If all that particular SQL Azure account can do is execute a few SPs so what if a malicious individual starts doing that. I will only allow a very limited amount of data to be uploaded before I require payment.
The users can only insert records using stored procedures which use the following:
SELECT #uName=SYSTEM_USER
and only select appropriate parent records. All stored procedures which users can execute would have the above as required to ensure they can only work with their own records.
All views will have embedded with them WHERE clauses such as
WHERE tbLoginName = SYSTEM_USER.
I'm new to SQL Server so I may be missing some fundamental concepts so I'd appreciate any and all comments.
The issue is, as pointed out on http://msdn.microsoft.com/en-us/library/ms189751.aspx:
In SQL Azure, only the server-level principal login (created by the provisioning process) or members of the loginmanager database role in the master database can create new logins.
Those accounts are also capable of alter and drop logins. So if you embed those accounts in the client application, you’re essentially granting every user permission to alter/drop other users accounts. While an average user won’t do that, a hacker will. So you cannot let a client application manage SQL Azure logins, unless only trusted users (such as your IT administrator) are permitted to use the app.
Best Regards,
Ming Xu.
I would like to point out a potential issue in the approach you mentioned: Your master SQL Azure account need to have privilege to create new accounts and grant them access to particular tables. This means your master account itself need to also have access to all those tables. If you store the master account on the client side, a clever user will get access to all users data.
From my experience, connecting to a database directly from a client side application will almost always make your solution less secure. You can do that for testing purposes, but in a real world solution, I would like to suggest you to use a service. You can host the service in Windows Azure. Then the service will access the database, and client application can only access the service. In this way, you can authenticate clients using any mechanisms you like, such as ASP.NET membership.
Best Regards,
Ming Xu.
You are essentially creating a physical two-tier database connection, allowing a client application to connect directly to the database. This is a problem in many ways, including security and performance. From a security standpoint, not controlling from where your customers will connect, you will need to keep your firewall rule wide open for anyone in the world to try to hack every customer uid/pwd. And instead of having only 1 user id to play with, hackers will have up to 1,000...
The second issue is performance. You applications will be unable to leverage connection pooling, creating undue stress on your database server and possibly hitting throttling issues at some point. Using a web service, with ASP.NET membership to manage logins, and using a service account (i.e. the same uid/pwd) to get data will ensure you will leverage connection pooling correctly if you keep the connection string the same for all your requests.
With a web service layer you also have a whole slew of new options at your fingertips that a two-tier architecture can't offer. This includes centralizing your business and data access logic, adding caching for improved performance, adding auditing in a centralized location, allowing to make updates to parts of your applications without redeploying anything at your customer locations and so much more...
In the cloud, you are much better off leveraging web services.
My 2 cents.

Using SQL Server Users and Roles as an authorization database for an intranet web application?

I have a question that really feels like I should have an easy answer to, but for one reason or another I haven't been able to totally reason around it.
I'm embarking on development of an ASP.NET MVC3 intranet application, and I'm currently working on designing authentication & authorization. We're forced to use basic authentication in our environment, and we use Active Directory, so the authorization part is generally taken care of. Unfortunately our role/user hierarchy in active directory doesn't mirror what I need for the roles in the application, so I'm going to have to define my own.
I'm using SQL Server, so I was originally thinking of using stored procedures for all DML, and then creating roles and adding users in roles in SQL Server, and then controlling access to the stored procedures via those roles. I was also thinking I could query for those SQL Server database-level users & roles in order to use that as the source of authorization info in the application itself. That originally seemed like a great idea, but it doesn't seem like a popular one (for one, it seems the queries for that are a little long and messy for what they produce). Alternatively, would it be better to have the web app impersonate a user for all queries to the server, and then implement a user/role database with my own schema, and only authorize on the application side?
It originally seemed that authorizing on both the application and database side would be a good thing for security, and using the SQL Server user/role objects means that the user and role data wouldn't need to be stored in two places.
I did see some potentially relevant discussion at Best practice on users/roles on SQL Server for a web application, but I think this is a different question overall.
Thanks!
I recommend creating a sql login that the web application will use to connect to sql server. This way you are not impersonating any specific AD account which may get deleted, disabled in the future and can control the user strickly in SQL Server.
I would then recommend implementing roles based authentication in your application. This will enable you to create users and roles that are custom to your application and then assign users to them. This way if a user tries to access a resource that their role is not allowed it will not do any work. Here is a demo app based on this principle http://www.codeproject.com/KB/web-security/rolesbasedauthentication.aspx.

What are the best practices on MS-SQL when Windows Authentications is not an option?

What is the best option for a windows application that uses SQL server authentication? Should I create a single SQL account and manage the users inside the application (using a users table). Or should I create a SQL server account for each user. What is your experience? Thank you!
Depends on whether the username/password for the SQL server would be exposed to the user, and whether that would be a problem. Generally for internal apps (in smaller organisations), one would trust the users not too log in directly to the sql server. If you have a middleware layer (ie webservices) the password can be hidden from user.
I prefer to use a general login for the DB and manage users in the application. Even if you do create a login to sql for each application user, they could still connect directly, so why not just use a generic sql login that is easier to manage. This is of course assuming all users have the same accesses.
One good practice, if the users potentially can get direct access to the db, would be to grant access only through Stored Procedures and not directly to tables, so that only certain actions can be performed. Steer away from writing business logic or security checks (except basic ones) within the stored procs.
One way I would solve your problem is to write some webservices that check security and does your CRUD (via datasets, etc), but again it depends on the app and environment.
In summary if you have a middle layer or all users have the same access manage the user within the application and use a single user login. Otherwise use a login per user or role.
One option that I have used in the past is to use the ASP.NET Membership Provider. It makes authentication a breeze to use. The only drawback that I saw was that it added a bunch of tables to your database.
The code for using it is very straight-forward.
Here's a blog post about using this in a Windows app. http://msmvps.com/blogs/theproblemsolver/archive/2006/01/12/80905.aspx Here's another article with more details. http://www.c-sharpcorner.com/UploadFile/jmcfet/Provider-basedASP.NET10162006104542AM/Provider-basedASP.NET.aspx
Here's another article that talks about using it with Windows applications: http://www.theproblemsolver.nl/usingthemembershipproviderinwinforms.htm
Google for "ASP.NET 2.0 Membership Provider", and you will get plenty of hits.
What about having SQL accounts based on the level of permissions needed for the task. For example you could have a read only account just used for reporting if your system has a lot of reporting. You would also need an account what has write access for people to change their passwords and other user admin tasks.
If you have situations where certain users are only going to have access to certain data I would have separate accounts for that data. The problem with using 1 account is you are saying that there is no SQL injection anywhere in your application. That is something everyone would strive for but sometimes perfect security is not possible, hence the multi-pronged approach.

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