AWS Permission Sets vs Control Tower SSO

1. AWS Control Tower SSO

Purpose: Provides a managed way to centrally set up and govern multiple AWS accounts with pre-configured security and governance best practices.

Integration: Built on top of AWS IAM Identity Center (formerly AWS SSO).

Primary Use Case:

• Centralized identity management across all AWS accounts in your organization.
• Simplifies user access management in a multi-account environment.

Features:

• Users log in via a single portal to access multiple AWS accounts.
• Integrates with existing identity providers (IdPs) like Azure AD, Okta, etc.
• Works with Control Tower to automatically apply baseline guardrails and account structures.

2. AWS Permission Sets

Purpose: Define what permissions users get when they access an AWS account via IAM Identity Center (SSO).

Integration: Used within Control Tower SSO / IAM Identity Center to assign access to AWS accounts.

Primary Use Case:

• Assign role-based permissions to groups or users.
• Can define permissions using AWS managed policies, custom policies, or a combination.

Features:

• Can be reused across multiple accounts.
• Can assign session duration, permission boundaries, and MFA requirements.
• Supports fine-grained control over user permissions in multi-account setups.

Key Differences

Aspect	Control Tower SSO	Permission Sets
Function	Centralized identity access across multiple accounts	Defines permissions/roles for users within SSO
Scope	Multi-account user login and governance	Specific permissions in each account
Setup	Part of Control Tower landing zone	Created and assigned inside IAM Identity Center
Granularity	Account-level access	Role/permission-level access inside accounts

How They Work Together

1. Control Tower SSO provides the portal and identity integration for all users.
2. Permission Sets are assigned to users or groups to define exactly what they can do in each AWS account they have access to.
3. Example:
   • Control Tower SSO gives Alice access to accounts Dev and Prod.
   • Permission Sets assign AdministratorAccess in Dev and ReadOnlyAccess in Prod.