Within my SQL server logs, I am showing a successful login to a database from an account (SERVER\loginname) that I cannot find in either Security > Logins OR Database > Security > Users. This login is being used by a program to execute a task (which it does successfully), so it's not a security compromise, but I cannot for the life of me figure out where it is and I need to find it to make an adjustment.

A couple more notes: I do remember adding this specific login a while back and there was something special about how I had to do it because it is not a domain account. Instead, it uses pass through authentication (same local account name on the app and SQL server with the same password). I cannot use it to login via SSMS. It is not a part of a group membership. It is not showing when I do a SELECT from the master syslogins table.

Does anyone have any ideas for my brain-fart?

  • 1
    Did you look in sys.server_principals which replaces sys.syslogins if you're on 2005+? I would triple check group membership if you still can't see it in there.
    – Jon Seigel
    May 1 '14 at 2:40
  • @JonSeigel sys.server_principals also isn't showing it. And I know it isn't a group membership because I don't have any groups that have ownership to that database. I'm completely dumbfounded right now. May 1 '14 at 14:57
  • To confirm, BUILTIN\Administrators and BUILTIN\Users are not logins on the instance, correct?
    – MattyZDBA
    May 1 '14 at 16:21
  • @MattyZDBA That is correct. These logins are a part of the BUILTIN\Administrators group, but it is not mapped to the database. May 1 '14 at 17:15

Can you try running the following:

EXEC xp_logininfo @acctname = 'SERVER\loginname', @option='all';

This should return the SQL login the Windows user is being authenticated as.

Reference here.

  • Well, we're getting somewhere. It is saying that it is a part of the BUILTIN\Administrators group. However, this group is NOT mapped to that database. I have double and triple checked at both the Security > Logins level as well as Database > Security > Users. How is that possible that it is still authenticating successfully without it being explicitly mapped? May 1 '14 at 17:15
  • 1
    By default, BUILTIN\Administrators is mapped to the sysadmin fixed server role and therefore has the same permissions as the SA login
    – MattyZDBA
    May 1 '14 at 17:43
  • @MattyZDBA The owner of the database is not sa, however. I am using a separate sysadmin credential for ownership. Or would that not matter? To further troubleshoot, I have also eliminated all users from the database except dbo, guest, INFORMATION_SCHEMA, and sys. I am suspecting it is under the dbo login. However, I attempted to use another local administrator account that is setup exactly like this one (credentials on both app and SQL for pass-through) to execute the task in the program, and I am getting Login unsuccesful. May 1 '14 at 19:40
  • Does BUILTIN\Administrators have a login on the server? And if so, is it a member of one of the fixed server roles? The fixed server roles will provide database-level access without having a user account in a database. May 6 '14 at 14:27

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