Description

The log_min_duration_statement flag defines the minimum execution time (milliseconds) of a statement, where the total duration of the statement is logged. Ensure that log_min_duration_statement is disabled by setting the value to -1. This will disable statement logging.

Rationale

SQL statement logs may include sensitive information that should not be recorded in the logs. This recommendation is applicable to PostgreSQL database instances.

Impact

Turning on logging will increase the required storage over time. Mismanaged logs may cause your storage costs to increase. Setting custom flags using the command line on certain instances will cause all omitted flags to be reset to defaults. This may cause you to lose custom flags and could result in unforeseen complications or instance restarts. Because of this, it is recommended that you apply these flag changes during a period of low usage.

Remediation

From the 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 PostgreSQL instance where the database flag needs to be enabled.
3. Click Edit.
4. Scroll down to the Flags section.
5. Click Add item to set a flag that has not been set on the instance before. Choose the flag log_min_duration_statement from the drop-down menu and set a value of -1.
6. Click Save.
7. Confirm the changes under the Flags section on the Overview page.

From the command line

1. List all Cloud SQL database instances using the following command:

   gcloud sql instances list
   

2. Configure the log_min_duration_statement flag for every PosgreSQL database instance using the below command:

   gcloud sql instances patch <INSTANCE_NAME> --database-flags log_min_duration_statement=-1
   

   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

By default log_min_duration_statement is set to -1.

References

1. https://cloud.google.com/sql/docs/postgres/flags
2. https://www.postgresql.org/docs/current/runtime-config-logging.html#RUNTIME-CONFIG-LOGGING-WHAT

Additional Information

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 does not require restarting the Cloud SQL instance.

CIS controls

Version 8, 8.5: Collect Detailed Audit Logs

• Configure detailed audit logging for enterprise assets containing sensitive data. Include event source, date, username, timestamp, source addresses, destination addresses, and other useful elements that could assist in a forensic investigation.

Version 7, 6.3: Enable Detailed Logging

• Enable system logging to include detailed information such as an event source, date, user, timestamp, source addresses, destination addresses, and other useful elements.