Introduction

In complex AWS environments, managing user access across multiple accounts can be challenging. AWS Single Sign-On (SSO) offers a streamlined solution. This blog post guides you through setting up a centralized user management system in AWS using AWS SSO with SAML integration, allowing seamless access control across multiple AWS accounts.

Prerequisites

• AWS Organization setup with multiple accounts.

• A central AWS account for user management.

• Additional AWS accounts for different environments (e.g., development, production).

Step-by-Step Guide

1. Setting Up AWS SSO in the Central Account

• Enable AWS SSO: In your AWS Organization's master account, enable AWS SSO. AWS SSO simplifies managing user access across all your AWS accounts and applications.

• Configure Identity Source: Connect AWS SSO to your identity source. This could be an AWS SSO internal identity store, Active Directory, or an external identity provider (IdP) compatible with SAML 2.0.

• Create Users and Groups: In AWS SSO, create users and organize them into groups based on their roles or access requirements. If using an external IdP, manage users there.

2. Creating AWS SSO Applications

• Define Applications: In the AWS SSO dashboard, define applications for each AWS account (development and production). These applications represent the access permissions to each account.

• Configure SAML: For each application, configure SAML integration. AWS provides a metadata file for SSO applications which you'll use in the next steps.

3. Configuring Development and Production Accounts

• Create SAML Identity Providers: In both your development and production accounts, create SAML 2.0 Identity Providers (IdP). Use the metadata file from your central account's AWS SSO application.

• Create IAM Roles for Cross-Account Access: Create IAM roles in these accounts. These roles will trust the SAML IdP and define the permissions that the SSO users will have.

• Establish Trust Relationships: Edit the trust relationships for these roles to establish a trust with the SAML IdP in your central account.

4. User Access Workflow

• Login through AWS SSO: Users log in to AWS SSO (via the user portal) using their credentials.

• Select the Environment: Users choose the AWS account (development or production) they wish to access.

• Assume Roles: They then select the role to assume based on the permission sets assigned in AWS SSO.

• Access Management Console: Users are directed to the AWS Management Console for the chosen account with the permissions of the assumed role.

Security Considerations

• Enforce Strong Authentication: Implement strong password policies and multi-factor authentication (MFA) for enhanced security.

• Least Privilege Principle: Assign minimal necessary permissions to each role to minimize risk.

• Regular Audits: Periodically review your configuration, including user access levels and permission sets.

Conclusion

This setup centralizes user management, enhances security, and simplifies access across multiple AWS environments. It streamlines operations for organizations with complex AWS infrastructures, offering a scalable and secure solution for cloud access management.