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gcp

Cloud SQL database instance requires SSL for all incoming connections

cloudsql_instance_ssl_connections
Service: cloudsqlSeverity: high
OfficialBuilt-inVerified
Categories:encryption
Resource Type:sqladmin.googleapis.com/Instance

Cloud SQL instances enforce SSL/TLS-only connections, rejecting plaintext traffic. The connection policy requires encryption for all clients (e.g., ENCRYPTED_ONLY or TRUSTED_CLIENT_CERTIFICATE_REQUIRED) instead of allowing both encrypted and unencrypted connections.

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Risk

Without enforced TLS, database traffic is exposed to interception.

  • MITM can read creds and query results (confidentiality)
  • Inject/alter statements to corrupt data (integrity)

Mixed modes cause accidental plaintext use on public or untrusted networks.

Run this check with Prowler

Run in Prowler Cloud
Run
prowler gcp --checks cloudsql_instance_ssl_connections

Recommendation

Require TLS for all connections. Prefer TRUSTED_CLIENT_CERTIFICATE_REQUIRED or use Cloud SQL Auth Proxy/Connectors for encrypted, authenticated channels.

  • Disallow mixed plaintext/SSL modes
  • Rotate and monitor certificates
  • Combine with least privilege and private access

Remediation

CLI

gcloud sql instances patch <INSTANCE_NAME> --ssl-mode=ENCRYPTED_ONLY

Terraform

resource "google_sql_database_instance" "<example_resource_name>" {
  name             = "<example_resource_name>"
  region           = "<region>"
  database_version = "<database_version>"

  settings {
    tier = "<tier>"
    ip_configuration {
      ssl_mode = "ENCRYPTED_ONLY" # Critical: only allow SSL/TLS-encrypted connections
    }
  }
}

Other

1In Google Cloud Console, go to Cloud SQL > Instances
2Click your instance name
3Open Connections > Security tab
4Select "Allow only SSL connections"
5Click Save

Check Code

from prowler.lib.check.models import Check, Check_Report_GCP
from prowler.providers.gcp.services.cloudsql.cloudsql_client import cloudsql_client


class cloudsql_instance_ssl_connections(Check):
    def execute(self) -> Check_Report_GCP:
        findings = []
        for instance in cloudsql_client.instances:
            report = Check_Report_GCP(metadata=self.metadata(), resource=instance)
            report.status = "PASS"
            report.status_extended = (
                f"Database Instance {instance.name} requires SSL connections."
            )

            if (instance.ssl_mode == "ALLOW_UNENCRYPTED_AND_ENCRYPTED") or (
                instance.ssl_mode == "SSL_MODE_UNSPECIFIED" and not instance.require_ssl
            ):
                report.status = "FAIL"
                report.status_extended = f"Database Instance {instance.name} does not require SSL connections."

            findings.append(report)

        return findings

References