How do you secure your Redshift database from external security threats?

First, Redshift clusters can be encrypted using AWS KMS (Key Management Service), which will encrypt the data at rest within the compute nodes.

For in-transit encryption, you can enable SSL connections. There is a parameter in the Redshift parameter group that can be set to true, which allows only SSL-secured connections to the cluster. For UNLOAD and COPY commands, it is recommended to not use IAM keys as credentials. Instead, create an IAM role and attach it to the cluster. Use that IAM role for UNLOAD and COPY commands.

You can also enable enhanced VPC routing to secure the UNLOAD and COPY command traffic such that the traffic flows only within the AWS VPC and not over the public internet.