6.3.2 Ensure that the 'cross db ownership chaining' database flag for Cloud SQL SQL Server instance is set to 'off'

Information

It is recommended to set cross db ownership chaining database flag for Cloud SQL SQL Server instance to off.

Rationale:

Use the cross db ownership for chaining option to configure cross-database ownership chaining for an instance of Microsoft SQL Server. This server option allows you to control cross-database ownership chaining at the database level or to allow cross-database ownership chaining for all databases. Enabling cross db ownership is not recommended unless all of the databases hosted by the instance of SQL Server must participate in cross-database ownership chaining and you are aware of the security implications of this setting. This recommendation is applicable to SQL Server database instances.

Impact:

Updating flags may cause the database to restart. This may cause it to unavailable for a short amount of time, so this is best done at a time of low usage. You should also determine if the tables in your databases reference another table without using credentials for that database, as turning off cross database ownership will break this relationship.

Solution

From Google Cloud Console

Go to the Cloud SQL Instances page in the Google Cloud Console by visiting https://console.cloud.google.com/sql/instances.

Select the SQL Server instance for which you want to enable to database flag.

Click Edit.

Scroll down to the Flags section.

To set a flag that has not been set on the instance before, click Add item, choose the flag cross db ownership chaining from the drop-down menu, and set its value to off.

Click Save.

Confirm the changes under Flags on the Overview page.

From Google Cloud CLI

Configure the cross db ownership chaining database flag for every Cloud SQL SQL Server database instance using the below command:

gcloud sql instances patch <INSTANCE_NAME> --database-flags "cross db ownership chaining=off"

Note: This command will overwrite all database flags previously set. To keep those and add new ones, include the values for all flags to be set on the instance; any flag not specifically included is set to its default value. For flags that do not take a value, specify the flag name followed by an equals sign ("=").

Default Value:

As you have to manually turn on this flag, the default value for this is 'On'. Though you would have had to design your database schema from the start to include this feature, it often is not enabled.

See Also

https://workbench.cisecurity.org/benchmarks/9562

Item Details

Category: ACCESS CONTROL, MEDIA PROTECTION

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|MP-2, CSCv7|14.6

Plugin: GCP

Control ID: a1e3e15ded8b7f4ceecca4d204665d9ceeb2c56924f413631beacb9805c69444