Best practices for IAM roles
IAM roles are a powerful tool, but they require careful management to ensure security:
- Enforce short-lived sessions: Limit the duration of sessions to the minimum required for the task. This reduces the window of opportunity for any potential misuse of the role’s permissions.
- Limit trust: Be selective about which identities are allowed to assume a role. Use trust policies to define these identities explicitly.
- Enforce mandatory MFA: For high-privilege roles granting access to sensitive or critical AWS resources that can be assumed by human users, enforce the use of MFA. This adds an additional layer of security, ensuring that even if a user’s primary credentials are compromised, the role remains protected.
- Use roles over user access keys: When granting permissions to AWS resources, prefer using roles over IAM user’s access keys. Roles provide temporary credentials, reducing the risk associated with long-term credentials. By using roles, you eliminate the need to share or embed permanent AWS access keys, thereby enhancing security. This approach ensures that permissions are only granted for the duration they are required, minimizing potential exposure.
- Limit service-link roles: Ensure service-linked roles are assumed only by the AWS service they are designed for, not by IAM users or other roles. Assign each service-linked role to a single AWS service and avoid granting additional permissions beyond what is necessary for the service’s operation, maintaining the principle of least privilege.
- Use descriptive naming and tagging: Ensure role names indicate their purpose and use tags to categorize them. Most AWS accounts end up with a lot of roles created, so this is particularly important here.
- Regularly review and audit roles: While roles can be used to grant temporary access for specific tasks, it is crucial to monitor and log such accesses. This ensures that the permissions are not misused and provides an audit trail for any actions performed during these sessions. Regularly assess the roles in your AWS environment, removing obsolete ones and adjusting permissions as necessary, ensuring they adhere to the principle of least privilege.
Having explored the roles of IAM users, groups, and roles in detail, let’s turn our attention to how AWS accommodates external identities and federations, further expanding the horizons of identity management.