An S3 bucket is a logical container for storing objects such as files, logs, images, and backups.
IAM resource-based policies can be used to control access to S3 buckets and protect sensitive data from unauthorized access and unintended exposure. AWS provides several mechanisms for this, including encryption at rest and in transit, blocking public access and unsafe ACLs, applying fine-grained IAM and bucket policies, and restricting access to specific networks using VPC endpoints.
In this Cloud Lab, you’ll learn how to secure S3 buckets using multiple layers of protection.
We’ll start by creating a bucket that requires server-side encryption with SSE-S3 and rejects any unencrypted uploads. Next, we’ll enforce encryption in transit by requiring SSL/TLS for all S3 requests. We’ll then create another bucket with ACLs enabled and explicitly deny PutObject requests that attempt to apply public-read or public-read-write ACLs.
After that, we’ll restrict bucket access to a specific VPC endpoint and further tighten permissions using a VPC endpoint policy.
Finally, we’ll validate these controls by launching an EC2 instance in the VPC and testing each restriction. By the end of the lab, you’ll understand the core security mechanisms used to protect S3 buckets and how to apply them in practice.
The architecture diagram below shows the provisioned infrastructure:
