Information
The concept of least privilege must be applied to SQL Server processes, ensuring that the processes operate at privilege levels no higher than necessary to accomplish required organizational missions and/or functions. Organizations consider the creation of additional processes, roles, and SQL Server accounts as necessary to achieve least privilege. Organizations also apply least privilege concepts to the design, development, implementation, and operations of SQL Server and the OS.
Unauthorized access to sensitive data or SQL Server control may compromise the confidentiality of personnel privacy, threaten national security, compromise a variety of other sensitive operations or lead to a loss of system control. Access controls are best managed by defining requirements based on distinct job functions and assigning access based on the job function assigned to the individual user.
SQL Server's 'Create server role' permission is a high server-level privilege that must only be granted to individual administration accounts through roles, and users who have access must require this privilege to accomplish the organizational missions and/or functions. , If the 'Create server role' permission is granted to roles that are unauthorized to have this privilege, then this access must be removed.
Additionally, the permission must not be denied to a role, because that could disable a user's legitimate access via another role.
The fix for this vulnerability specifies the use of REVOKE. Be aware that revoking a permission that is currently denied to a role or user does not necessarily disable the permission. If the user or role can inherent the permission from another role, revoking the denied permission from the user or the first role can effectively enable the inherited permission.
Solution
Remove the 'Create server role' permission access from the role that is not authorized by executing the following query:
REVOKE Create server role TO <'role name'>