How can we avoid somebody to access the MDF data by doing User Instance connection?

I created a database that will be distributed to my customers. This database is running on an Instance of SQL Server 2005 Express edition. I removed the admin logins from my SQL Server Instance so in theory, only my application connecting itself using the Sql Server autenthication will be able to be access the data (using "sa" having a password that I set at the installation).

For now, all this is working fine and after some tests, I haven't been able to access the data in any ways except by using the "sa" and the password my app is the only one to know.

But the problem is coming from a security leak when using User Instance. Indeed, I've been able to create a program getting the content from my MDF file. If somebody try to get connected using User Instance on his own SQL Server instance, he will be able to reach the data.

How could I prevent this to happend? Is there a property or something that could be set into the database that would prevent the database (mdf file) to be used with User Instance?

Thanks!

Hi,

AFAIK their is no way to restrict access to MDF/LDF files physically... refer below thread which has discussion the same issue.

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=52094&SiteID=1

Hemantgiri S. Goswami

|||

Alright, but what about the User Instance? Is there a way to prevent somebody of getting connected on a server using our MDF file and the User Instance option into his connection string?

|||No, you wil lhave to do this via NTFS permissions.

HTH, Jens K. Suessmeyer.

http://www.sqlserver2005.de