Improving Web Application Security: Threats and - CGISecurity

Chapter 18: Securing Your Database Server 531This adds the new login to the sysadmin server role. To delete the BUILTIN\Administrators login1. Start Enterprise Manager.2. Expand Microsoft SQL Server, expand SQL Server Group, and then expand yourSQL Server.3. Expand the Security folder, and select Logins. If BUILTIN\Administratorsappears in the list of logins, right-click it, and then click Delete to remove thelogin.For more information about reconfiguring the SQL service accounts after theinstallation, see the MSDN article, “Changing Passwords and User Accounts”at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/instsql/in_afterinstall_4p0z.asp.Do Not Grant Permissions for the Public RoleAll databases contain a public database role. Every other user, group, and role is amember of the public role. You cannot remove members of the public role. Instead,do not grant the permissions for the public role that grant access to your application’sdatabase tables, stored procedures, and other objects. Otherwise, you cannot get theauthorization that you want using user-defined database roles because the public rolegrants default permissions for users in a database.Additional ConsiderationsAlso consider the following recommendations when configuring SQL Server logins,users, and roles:● Limit the members of sysadmin. To make sure there is individual accountability,restrict the number of accounts that are members of the sysadmin role. Ideally, nomore than two users are members of this role.● Grant restricted database permissions. Assign accounts only the absoluteminimum permissions required to do a job. Avoid using the built-in roles, such asdb_datareader and db_datawriter. These roles do not provide any authorizationgranularity and these roles have access to all of your custom database objects.● Do not change the default permissions that are applied to SQL Server objects.In versions of SQL Server earlier than Service Pack 3, the public role does haveaccess to various default SQL Server database objects. With Service Pack 3, thesecurity design has been reviewed and security has been improved by removingthe public role where it is unnecessary and by applying more granular role checks.