Ensure the 'cross db ownership chaining' database flag for Cloud SQL on the SQL Server instance is set to 'Off'

From Google Cloud 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 where the database flag needs to be enabled
3. Click EDIT
4. Scroll down to the Flags section
5. To set a flag that has not been set on the instance before, click ADD A DATABASE FLAG, 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

Using 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 <instanceName> --database-flags "cross db ownership chaining=off"

Note: This command will overwrite all database flags that were 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.

References

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

Additional information

WARNING: This patch modifies database flag values, which may require the instance to be restarted. Check the list of supported flags https://cloud.google.com/sql/docs/sqlserver/flags - to see if your instance will be restarted when this patch is submitted.

Note: Some database flag settings can affect instance availability or stability, and remove the instance from the Cloud SQL SLA. For information about these flags, see Operational Guidelines.

Note: Configuring the above flag restarts the Cloud SQL instance.

Multiple Remediation Paths

Google Cloud

SERVICE-WIDE (RECOMMENDED when many resources are affected): Enforce Organization Policies at org/folder level so new resources inherit secure defaults.

gcloud org-policies set-policy policy.yaml

ASSET-LEVEL: Use the product-specific remediation steps above for only the impacted project/resources.

PREVENTIVE: Use org policy constraints/custom constraints and enforce checks in deployment pipelines.

References for Service-Wide Patterns

• GCP Organization Policy overview: https://cloud.google.com/resource-manager/docs/organization-policy/overview
• GCP Organization policy constraints catalog: https://cloud.google.com/resource-manager/docs/organization-policy/org-policy-constraints
• gcloud org-policies: https://cloud.google.com/sdk/gcloud/reference/org-policies

Operational Rollout Workflow

Use this sequence to reduce risk and avoid repeated drift.

1. Contain at Service-Wide Scope First (Recommended)

• Google Cloud: apply organization policy constraints at org/folder scope.

gcloud org-policies set-policy policy.yaml

2. Remediate Existing Affected Assets

• Execute the control-specific Console/CLI steps documented above for each flagged resource.
• Prioritize internet-exposed and production assets first.

3. Validate and Prevent Recurrence

• Re-scan after each remediation batch.
• Track exceptions with owner and expiry date.
• Add preventive checks in IaC/CI pipelines.