IAM Role Best Practices for Multi-Account Architecture

Question

In a multi-account AWS environment managed using AWS Organizations, what are the best practices for designing IAM roles and policies to maintain the least privilege while supporting efficient cross-account access?

Kazi Md Saiful Alam · Accepted Answer

Following are some Best Practices adopted for Multi-Account Architecture:
1.	Centralize IAM Role Management: Create a centralized account for managing cross-account roles to ensure consistency and simplify auditing.
2.	Grant Fine-Grained Permissions: Assign IAM policies with the least privilege necessary for specific tasks, avoiding wildcard actions like s3:*.
3.	Enable Cross-Account Access with Roles: Use IAM roles with explicit trust relationships to allow secure access between accounts.
4.	Tag and Organize Resources: Use resource tags and conditions in policies for fine-grained access control.
5.	Monitor and Audit with AWS IAM Access Analyzer: Continuously review cross-account access permissions for unintended exposure.
6.	Implement Role Chaining with MFA: Require multi-factor authentication (MFA) for sensitive operations involving role chaining across accounts.
7.	Leverage AWS Resource Access Manager (RAM) to securely share resources between accounts without needing broad permissions.

IAM Role Best Practices for Multi-Account Architecture

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