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6.3.2 Set the 'cross db ownership chaining' database flag for Cloud SQL on SQL Server instance to 'off' (Automated)​

Profile Applicability​

• Level 1

Description​

Best practices recommend setting cross db ownership chaining database flag for Cloud SQL on 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.

Audit​

From Console:

  1. Go to the Cloud SQL Instances page in the Google Cloud Console.
  2. Select the instance to open its Instance Overview page
  3. Ensure the database flag cross db ownership chaining that has been set is listed under the Database flags section.

From Command Line:

  1. Ensure the below command returns off for every Cloud SQL SQL Server database instance:
gcloud sql instances list --format=json | jq '.settings.databaseFlags[] | select(.name=="cross db ownership chaining")|.value'

Remediation​

From Console:

  1. Go to the Cloud SQL Instances page in the Google Cloud Console by visiting: https://console.cloud.google.com/sql/instances.
  2. Select the SQL Server instance for which you want to enable to database flag.
  3. Click Edit.
  4. Scroll down to the Flags section.
  5. To set a flag that is new to the instance, click Add item, choose the flag cross db ownership chaining from the drop-down menu, and set its value to off.
  6. Click Save.
  7. Confirm the changes under Flags on the Overview page.

From Command Line:

  1. Configure the cross db ownership chaining database flag for every Cloud SQL on SQL Server database instance using the below command:
gcloud sql instances patch <instance_name> --database-flags "cross db ownership chaining=off"
note

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

References​

https://cloud.google.com/sql/docs/sqlserver/flags
https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/cross-db-ownership-chaining-server-configuration-option?view=sql-server-ver15

Additional Information​

danger

This patch modifies database flag values, which may require you to restart your instance. The list of supported flags is on this page, along with details of which flags require a restart: https://cloud.google.com/sql/docs/sqlserver/flags.

note

Some database flag settings can affect instance availability or stability, and remove the instance from the Cloud SQL Service-Level Agreement (SLA). For information about these flags, see Operational Guidelines.

note

Configuring the preceding flag does not restart the Cloud SQL instance.

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