What's the issue?
Only approved groups and users should be included in the local Administrators role on the server of your SQL Server instance.
Why is this a problem?
The local Administrators role in Windows is the most powerful on your server, as members of this role can do anything on your server - including adding themselves as members of the all-powerful sysadmin role in SQL Server. Anyone in the sysadmin role can not only drop and create objects in any database, but can also create backups of your data, change any other users permissions, or use a Windows shell to execute any kind of script.
What should you do about this?
Routinely review the members of the local Administrators group on your server to ensure that only a select few users are required to belong in this group with the highest of permissions.
Vulnerability
Category
What do the Vulnerability Levels mean?
0 - Information only. This is stuff you should know about your instances like version and service account used, but if you don't know it…well, now you do.
1 - High vulnerability requiring action. These are the issues that could most likely lead to your company being front page news for all the wrong reasons. If your instances have any results at this level then we recommend cancelling that 3-martini lunch and instead huddling with your team to figure out when to address these issues.
2 - High vulnerability to review. These include settings and assigned permissions you should review soon, if not immediately. These findings may not necessarily indicate a clear vulnerability, but we've found unexpected vulnerabilities in these categories at many, many clients.
3 - Potential vulnerability to review. These are configurations or assigned permissions you may be using that could lead to problems for users. Or maybe they're just required for your applications. Either way, we recommend reviewing these to make sure these are correct.
4 – Low vulnerability with recommended action. These are typically security inconsistencies that should be addressed. They aren't likely to cause problems, but you should clean up the mess.