Assess the security of your document storage and retrieval system, focusing on user access control mechanisms. Review existing roles and permissions for different user groups (e.g., [UserRoles]) and verify whether the system adheres to the principle of least privilege. Recommend improvements to prevent unauthorized access, such as implementing two-factor authentication or encryption for sensitive documents. Consider the need for auditing capabilities to track user interactions with documents, and suggest a procedure for periodic security reviews. Provide a clear action plan for any required changes and specify a timeline for implementation.