Overview
Enabling the log_connections setting causes each attempted connection to the server to be logged, along with successful completion of client authentication. This parameter cannot be changed after the session starts.
Rationale
PostgreSQL does not log attempted connections by default. Enabling the log_connections setting will create log entries for each attempted connection as well as successful completion of client authentication which can be useful in troubleshooting issues and to determine any unusual connection attempts to the server. 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 via 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 you apply these flags changes during a period of low usage.
Remediation guidance
From Google Cloud Console
- Go to the
Cloud SQL Instancespage in the Google Cloud Console by visiting https://console.cloud.google.com/sql/instances - Select the PostgreSQL instance where the database flag needs to be enabled
- Click
EDIT - Scroll down to the
Flagssection - To set a flag that has not been set on the instance before, click
ADD A DATABASE FLAG, choose the flaglog_connectionsfrom the drop-down menu, and set its value toon - Click
SAVE - Confirm the changes under
Flagson theOverviewpage
Using Google Cloud CLI
Configure the log_connections database flag for every Cloud SQL PostgreSQL database instance using the below command.
gcloud sql instances patch <instanceName> --database-flags log_connections=on
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
By default log_connections is off.
References
- https://cloud.google.com/sql/docs/postgres/flags
- https://www.postgresql.org/docs/9.6/runtime-config-logging.html#RUNTIME-CONFIG-LOGGING-WHAT
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/postgres/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.
Query logic
These are the stored checks tied to this control.
The 'log_connections' database flag for Cloud SQL PostgreSQL instance is set to 'on'
Connectors
Covered asset types
Expected check: eq []
{ cloudSqlInstances( where: { engine: "postgresql" cloudProvider: "gcp" OR: [ { dbFlags_NONE: { name: "log_connections" } } { dbFlags_SOME: { name: "log_connections", value: "off" } } ] } ) { ...AssetFragment }}
Google Cloud