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Ensure the 'log_connections' database flag for Cloud SQL PostgreSQL instance is set to 'On'

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.

Category

Controls

Low

Applies to

Google Cloud

Coverage

null controls, 1 queries

Asset types

1 covered

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

  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. To set a flag that has not been set on the instance before, click ADD A DATABASE FLAG, choose the flag log_connections from the drop-down menu, and set its value to on
  6. Click SAVE
  7. Confirm the changes under Flags on the Overview page

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

  1. https://cloud.google.com/sql/docs/postgres/flags
  2. 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

Google Cloud

Covered asset types

CloudSQLInstance

Expected check: eq []

{ cloudSqlInstances( where: { engine: "postgresql" cloudProvider: "gcp" OR: [ { dbFlags_NONE: { name: "log_connections" } } { dbFlags_SOME: { name: "log_connections", value: "off" } } ] } ) { ...AssetFragment }}
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