Control: 1.21 Ensure IAM users are managed centrally via identity federation or AWS Organizations for multi-account environments

Description

In multi-account environments, IAM user centralization facilitates greater user control. User access beyond the initial account is then provided via role assumption. Centralization of users can be accomplished through federation with an external identity provider or through the use of AWS Organizations.

Centralizing IAM user management to a single identity store reduces complexity and thus the likelihood of access management errors.

Remediation

Perform the following action to check:

For multi-account AWS environments with an external identity provider...

1. Determine the master account for identity federation or IAM user management.
2. Login to that account through the AWS Management Console.
3. Click Services.
4. Click IAM.
5. Click Identity providers.
6. Verify the configuration.

Then..., determine all accounts that should not have local users present. For each account...

1. Determine all accounts that should not have local users present.
2. Login to the AWS Management Console.
3. Switch role into each identified account.
4. Click Services.
5. Click IAM.
6. Click Users.
7. Confirm that no IAM users representing individuals are present.

For multi-account AWS environments implementing AWS Organizations without an external identity provider...

1. Determine all accounts that should not have local users present.
2. Login to the AWS Management Console.
3. Switch role into each identified account.
4. Click Services.
5. Click IAM.
6. Click Users.
7. Confirm that no IAM users representing individuals are present.

Note: The remediation procedure will vary based on the individual organization's implementation of identity federation and/or AWS Organizations with the acceptance criteria that no non-service IAM users, and non-root accounts, are present outside the account providing centralized IAM user management.