Confirm Redshift clusters are not using default port 5439 to protect against non-targeted attacks.
Rationale
Using a custom port can protect your publicly accessible AWS Redshift clusters against potential brute-force and dictionary attacks. Although setting a custom port can help fend off these attacks, it is also recommended to restrict public access, use SSL to encrypt client connections to database clusters, and control cluster access through security groups and Network Access Control Lists (NACLs) to add an additional layer of security for your account.
Remediation
From the console
Follow the [Getting information about cluster configuration][7] docs to access your cluster configuration information. If the cluster has a port 5439, it is the default port. Modify the port number in the console.
