SQL Server Fixed Role Permissions

Roles and Permissions

Some of my recent articles have been focused on permissions and security. There is good reason for that – security is important and all too often it is mis-understood.

You can catch up with a couple of those articles here and here.

It is very important to understand who has what level of access within the server and databases on that server. Sometimes we see users being granted server or database access through the fixed roles available in SQL Server. How exactly do you know what permissions those individuals have via role membership? This article will help to reveal the permissions granted to the various roles and maybe a gotcha or two.

Finding Permissions

There is ample documentation on what the permissions are for each of the various fixed server and fixed database roles in SQL Server. Some of that documentation can be found here and here and here. With all of that documentation, you may be surprised to hear that it is not quite as easy to find the permissions of these roles via queries from within SQL Server – with a caveat. I am going to discuss some documented means to retrieve the permissions for the various roles and also discuss the pitfalls of these solutions.

What are the fixed roles again? Just in case you did not see them in the links from the previous paragraph, I will list the various fixed roles here.

Fixed Server Roles Fixed Database Roles
public public
sysadmin db_owner
securityadmin db_accessadmin
serveradmin db_securityadmin
setupadmin db_ddladmin
processadmin db_backupoperator
diskadmin db_datareader
dbcreator db_datawriter
bulkadmin db_denydatareader
db_denydatawriter

These default roles do have a unique set of permissions for each role. As noted, the permissions are documented well enough. Sometimes, it is preferable to just query the system to retrieve a list of the permissions for each role. This is especially true if one is in need of providing documentation for an auditor on who has what permission.

When trying to query for a list of permissions, one may feel as though they have fallen off their rocker just as the granny in this pic to the left.

Never fear, however, for there is a method to find the permissions of the fixed roles. Let’s take a look at what it takes to query the permissions associated to each fixed role.

System Queries

Unlike most principals, where one can query the various system catalogs to retrieve the permissions assigned to the principal, the fixed roles do not expose the assigned permissions in the same way. With fixed roles, there are two stored procedures that have been created to retrieve the permissions. These stored procedures are sp_dbfixedrolepermission and sp_srvrolepermission.

Immediately I have a “rocker moment” for each of these stored procedures. In the documentation there is a note that states the following.

This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.

When peaking into the secret sauce behind each of these stored procedures, there is nothing extraordinary to how the permissions are retrieved. In fact, both procedures reference a particular object in addition to the catalog view specific to the type of role (e.g server_principals or database_principals. This second object is called sys.role_permissions. Wait, I said there is no direct view or table to query with the permissions, right?

Let’s try to query that table.

Boom! We have just had another “rocker” moment. As it turns out, this table is the secret sauce to the fixed role permissions being accessible via query. This table can be queried from the stored procedures and can be queried direct – if it is queried from a DAC connection. Most will probably not connect to the DAC just to query the role permissions, so what can we do?

Here is a basic script showing what I have done.

In this script, I have taken the results from each of the stored procedures and dumped them into a temp table. Using this temp table, I can now join to this table to get a more complete list of the permissions in effect for various principals. Once that more complete list is made, then it can be handed to the auditors to satisfy them for at least a week before they ask again ;).

Now it is time for yet another “rocker” moment. Look carefully at the output from these stored procedures. Remember the notice that they will be removed (i.e. on the deprecation list)? It seems there is good reason to remove them from SQL Server – the permissions in sys.role_permissions is not being maintained. That is correct! There are permissions listed in the output of these procedures that are no longer applicable!

If the list is not entirely accurate, then what can be done to get an accurate list of permissions? As it turns out, it seems one may need to code a solution that has the permissions hard coded in the script – very similar to what these system stored procedures were doing.

Recap

Capturing fixed role permissions is possible through the use of two system stored procedures. Just like the red telephone booths, these stored procedures are soon to be a thing of the past. These stored procedures are deprecated and may be just as reliable as those old telephone booths.

Too bad there is not a better means to trap the permissions from these fixed roles. It would be really nice to be able to view them just the same as can be done with the other principals (users and logins).

Now go forth and Audit your roles.

PS

What is up with that weird granny pic? Well, it was a challenge from Grant Fritchey to use the image in a technical blog post. You can read the challenge invite over here. And yeah, I know it is some sort of Dr. Who thing.

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