https://pawelurbanek.com/s3-iam-config

Getting Started with AWS S3 IAM Policies Security Config for Rails Apps Storing files on S3 is for many developers, the first contact with AWS cloud. Unfortunately, the quick and easy configuration can be insecure. If you are uploading files to an S3 bucket but never configured a custom AWS IAM policy it’s possible that there’s a security issue in your app. In this tutorial, I will describe what IAM policies are and how to securely configure them when working with S3 in the Rails apps.