Disable "Contained Database Authentication" Flag for SQL Server Database Instances

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Risk level: Medium (should be achieved)

Ensure that "contained database authentication" database flag is disabled for your Google Cloud SQL Server database instances.

Security

Setting "contained database authentication" SQL Server engine flag to Off will prevent any databases on the server from being contained. This is important because the users within a contained database that have the ALTER ANY USER permission can grant access to the database without the knowledge or permission of the SQL Server administrator. Misconfigured contained databases are also prone to Denial of Service (DoS) attacks.

Note: Some database flag settings can affect instance availability and/or stability, and eventually remove the SQL Server instance from the Google Cloud SQL Service Level Agreement (SLA).


Audit

To determine if "contained database authentication" flag is disabled for your Cloud SQL Server database instances, perform the following actions:

Using GCP Console

01 Sign in to Google Cloud Management Console.

02 Select the Google Cloud Platform (GCP) project that you want to access from the console top navigation bar.

03 Navigate to Cloud SQL Instances dashboard at https://console.cloud.google.com/sql/instances.

04 Click inside the Filter tree box, select Type and SQL Server then press Enter, to list only the SQL Server database instances provisioned for the selected GCP project.

05 Click on the name (ID) of the database instance that you want to examine.

06 In the navigation panel, select Overview to access the configuration details of the selected instance.

07 In the Configuration section, under Database flags, check the configuration value set for the contained database authentication database flag. If contained database authentication is set to on, the "contained database authentication" database flag is enabled for the selected Google Cloud SQL Server database instance, therefore the instance configuration is not compliant.

08 Repeat step no. 5 – 7 to check the "contained database authentication" flag configuration for other SQL Server instances available within the selected project.

09 Repeat steps no. 2 – 8 for each project deployed in your Google Cloud account.

Using GCP CLI

01 Run projects list command (Windows/macOS/Linux) using custom query filters to list the IDs of all the Google Cloud Platform (GCP) projects available in your Google Cloud account:

gcloud projects list
	--format="table(projectId)"

02 The command output should return the requested GCP project identifiers:

PROJECT_ID
cc-ms-web-project-123123
cc-mobile-project-123123

03 Run sql instances list command (Windows/macOS/Linux) using custom filtering to describe the name of each SQL Server database instance provisioned for the selected Google Cloud project:

gcloud sql instances list
	--project cc-ms-web-project-123123
	--filter='DATABASE_VERSION:SQLSERVER*'
	--format="(NAME)"

04 The command output should return the requested database instance name(s):

NAME
cc-web-sql-server-instance
cc-app-sql-server-instance

05 Run sql instances describe command (Windows/macOS/Linux) using the name of the SQL Server database instance that you want to examine as identifier parameter and custom query filters to describe the "contained database authentication" flag configuration value set for the selected database instance:

gcloud sql instances describe cc-web-sql-server-instance
	--format=json | jq '.settings.databaseFlags[] | select(.name=="contained database authentication")|.value'

06 The command output should return the requested flag configuration value:

"on"

If the sql instances describe command output returns "on", the "contained database authentication" database flag is enabled for the selected Google Cloud SQL Server database instance, therefore the instance configuration is not compliant.

07 Repeat step no. 5 and 6 to verify the "contained database authentication" flag configuration value for other SQL Server instances created for the selected project.

08 Repeat steps no. 3 – 7 for each project available within your Google Cloud account.

Remediation / Resolution

To turn off the "contained database authentication" database flag for your Google Cloud Platform (GCP) SQL Server database instances, perform the following actions:

Using GCP Console

01 Sign in to Google Cloud Management Console.

02 Select the Google Cloud Platform (GCP) project that you want to access from the console top navigation bar.

03 Navigate to Cloud SQL Instances dashboard at https://console.cloud.google.com/sql/instances.

04 Click inside the Filter tree box, select Type and SQL Server then press Enter, to display only the SQL Server instances available for the selected project.

05 Click on the name/ID of the database instance that you want to reconfigure.

06 In the navigation panel, select Overview to access the configuration details of the selected instance.

07 Click on the Edit button from the dashboard top menu to access the instance edit mode.

08 In the Configuration options section, click on Flags and parameters to expand the panel with the database flags configured for the selected instance.

09 Find the contained database authentication flag and turn it off by selecting off from the flag configuration dropdown list. If the flag has not been set on the selected instance before, click Add item, choose the contained database authentication flag from the Choose one dropdown menu, and set its value to off. Click Close to close the panel.
IMPORTANT: Configuring the "contained database authentication" flag restarts automatically the selected database instance.

10 Click Save to apply the configuration changes.

11 Repeat step no. 5 – 10 to configure the required flag for other SQL Server database instances available within the selected project.

12 Repeat steps no. 2 – 11 for each project deployed in your Google Cloud account.

Using GCP CLI

01 Run sql instances patch command (Windows/macOS/Linux) using the name of the SQL Server database instance that you want to reconfigure as identifier parameters (see Audit section part II to identify the right resource), to disable the "contained database authentication" database flag for the selected SQL database instance:

gcloud sql instances patch cc-web-sql-server-instance
	--database-flags "contained database authentication=off"

Note: The sql instances patch command will overwrite all the database flags previously set. To keep those and add new ones, include the values for all flags to be set on the SQL Server instance. Any database flag not specifically included is set to its default value. For flags that do not take a value, specify the flag name followed by the equal sign ("=").
IMPORTANT: Configuring the "contained database authentication" flag restarts automatically the selected database instance.

02 Type Y to confirm the database configuration change:

The following message will be used for the patch API method.
{"name": "cc-web-sql-server-instance", "project": "cc-ms-web-project-123123", "settings": {"databaseFlags": [{"name": "contained database authentication", "value": "off"}]}}
WARNING: This patch modifies database flag values, which may require your 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.
Do you want to continue (Y/n)? Y

03 The output should return the sql instances patch command request status:

Patching Cloud SQL instance...done.
Updated [https://sqladmin.googleapis.com/sql/v1beta4/projects/cc-ms-web-project-123123/instances/cc-web-sql-server-instance].

04 Repeat step no. 1 – 3 to configure the required flag for other SQL Server database instances provisioned for the selected project.

05 Repeat steps no. 1 – 4 for each project created within your Google Cloud account.

References

Publication date Apr 12, 2021

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Disable "Contained Database Authentication" Flag for SQL Server Database Instances

Risk level: Medium