multi-account-multi-region-s3-access

Multi-Account Multi-Region S3 Access

Key	Value
Services	S3, IAM
Integrations	AWS CLI
Categories	Security; Multi-Account

Introduction

A demo application illustrating how to access S3 resources across different AWS accounts using bucket policies and IAM users with LocalStack. The script uses the following AWS profiles to simulate a cross-account scenario:

• Admin user of account A with account ID 000000000001
• Admin user of account B with account ID 000000000002
• Account A user — creates the S3 bucket and grants cross-account access via bucket policies
• Account B user — copies resources from Account A's source bucket into its own target bucket

Prerequisites

• A valid LocalStack for AWS license. Your license provides a LOCALSTACK_AUTH_TOKEN to activate LocalStack.
• Docker
• localstack CLI
• awslocal CLI
• Python 3 with pip

Check prerequisites

make check

Installation

make install

Start LocalStack

export LOCALSTACK_AUTH_TOKEN=<your-auth-token>
make start

Run the application

make run

The script sets up two AWS accounts with IAM users and bucket policies, then demonstrates cross-account S3 resource access.

License

This code is available under the Apache 2.0 license.