An AWS CodeBuild project is currently downloading a database population script from an S3 bucket using an unauthenticated request, which violates security policy. What is the most secure way to fix this?

The most secure solution involves removing public access to the S3 bucket, which is a critical security best practice. By granting the CodeBuild service role specific S3 read permissions, you leverage AWS IAM roles for secure, temporary credentials, eliminating the need for hardcoded keys. The AWS CLI automatically uses the CodeBuild service role's permissions when run within the CodeBuild environment, ensuring authenticated and authorized access. Adding the bucket name to AllowedBuckets doesn't inherently secure the S3 bucket itself or authenticate access. Enabling HTTPS basic authentication on S3 is not a native S3 feature for object access and is generally not recommended for programmatic access. Using hard-coded IAM access keys and secret access keys in the buildspec is a significant security vulnerability, as these credentials could be exposed.