This assumes you have already configured the aws command line tool. If not, check out my article on Getting Started with the AWS CLI.

• An IAM Policy allows certain actions (such create) on certain resources (such as EC2)
• An IAM User is typically a users account (such as john.doe) that contains an IAM Identity-Based Policy that allows certain actions (such as list) on certain resources (such S3)
• An IAM Role contains an IAM Policy that allows certain actions (such create) on certain resources (such as EC2) - Let's say the Identity-Based Policy attached to john.doe does NOT allow create S3 - john.doe could Assume a Role that allows create S3
  • Assume Role or Switch Role using Python boto3
  • Assume Role or Switch Role using Terraform
  • Assume Role or Switch Role using the AWS CLI
  • Often, a Role will have two Policies:
    • Trust Relationship
    • Permission Policy

The aws iam get-account-authorization-details command can be used to list details about users, groups, roles and policies.

aws iam get-account-authorization-details

And here is an example of how to limit the output using the --query option.

aws iam get-account-authorization-details --query 'UserDetailList[?UserName==`johndoe`]'

Something like this should be returned.

{
    "UserDetailList": [
        {
            "Path": "/",
            "UserName": "johndoe",
            "UserId": "AIDA123456789UA6B2DRP",
            "Arn": "arn:aws:iam::123456789012:user/johndoe",
            "CreateDate": "2022-09-13T11:13:03+00:00",
            "GroupList": [],
            "AttachedManagedPolicies": [
                {
                    "PolicyName": "AdministratorAccess",
                    "PolicyArn": "arn:aws:iam::aws:policy/AdministratorAccess"
                }
            ],
            "Tags": []
        }
    ],
    "GroupDetailList": [],
    "RoleDetailList": . . .