IAM Policy

Difference between Trust Policy and Permission Policy

In AWS IAM, there are two main types of policies that are associated with roles:

1. Trust Policy: Specifies who or what can assume the role.
2. Permissions Policy: Specifies what actions the role can perform and on which resources.

Trust Policy

• Purpose: Defines the entities that are trusted to assume the role.
• Attachment: Each role can have only one trust policy.
• Example: Allowing AWS Lambda to assume a role.

Permissions Policy

• Purpose: Defines the permissions (actions on resources) that are granted to the role.
• Attachment: Each role can have multiple permissions policies attached to it.
• Types:
  • Managed Policies: Can be AWS managed or customer managed and can be reused across multiple roles.
  • Inline Policies: Defined directly within the role and cannot be reused.