Demystifying AWS Policies and Permissions

Introduction

AWS (Amazon Web Services) policies and permissions form the bedrock of secure and efficient cloud management. This comprehensive guide aims to demystify these core concepts, offering clear explanations and providing references for further reading. Given the expansive nature of this topic, we at Cloudericks.com understand the importance of staying current. Therefore, we commit to continuously updating this blog post based on further research and valuable user feedback.

1. AWS Identity and Access Management (IAM)

• What is IAM?
  • IAM securely controls access to AWS services and resources.
• Key Concept: Users, Groups, and Roles
  • Users are individual accounts, Groups are collections of users, and Roles are for granting permissions.

2. IAM Policies

• What are IAM Policies?
  • Documents defining permissions, attachable to users, groups, or roles.
• Types of Policies
  • Managed Policies (created by AWS) and Customer Managed Policies (created by you).

3. Permissions and Policy Structure

• Understanding Permissions
  • Permissions specify actions allowed or denied on resources.
• Policy Structure
  • A JSON format with Effect, Action, Resource, and Condition.

4. IAM Identity Center (formerly AWS SSO)

• What is IAM Identity Center?
  • Manages access to AWS accounts and applications using SSO.
• Permission Sets
  • Define user access levels, similar to IAM roles.

5. Resource-Based Policies

• What are Resource-Based Policies?
  • Policies attached directly to AWS resources (like S3 buckets), specifying who has access to that resource.
• Differences from IAM Policies
  • Unlike IAM policies, they are attached to resources rather than users or roles.

6. Session Policies

• What are Session Policies?
  • Policies that you pass when you assume a role or federate a user. They limit permissions for the duration of the session.
• Use Cases
  • Useful for temporary access control, providing an additional layer of security.

7. Service Control Policies (SCPs)

• What are SCPs?
  • SCPs are used in AWS Organizations to manage permissions across multiple AWS accounts.
• Functionality
  • They set boundaries for each account, controlling what actions users and roles can perform.

8. Permission Boundaries

• What are Permission Boundaries?
  • A way to delegate administration tasks and limit the maximum permissions a user or role can have.
• Implementation
  • Applied to IAM users and roles to prevent them from exceeding certain permission thresholds.

9. Amazon Resource Names (ARNs)

• What are ARNs?
  • Unique identifiers for AWS resources, used in IAM policies.
• ARN Format
  • arn:partition:service:region:account:resource.

10. Access Control Lists (ACLs)

• What are ACLs?
  • Used in Amazon S3 for bucket and object access management.

11. Security Best Practices

• Principles to Follow
  • Practice least privilege, update IAM policies regularly, and use advanced features like SCPs for cross-account control.

Conclusion 

This guide provides a detailed overview of AWS policies and permissions, including advanced topics essential for robust cloud security and management.

References:

• AWS IAM Documentation: AWS Identity and Access Management Documentation
• IAM Identity Center Overview: AWS IAM Identity Center
• Understanding IAM Policies and Permissions: AWS IAM Policies and Permissions
• Understanding Access Policies: AWS IAM Access Policies
• ARNs and Namespaces: Amazon Resource Names (ARNs)