Role-Based Access Controls (0903.2171v2)

Abstract: While Mandatory Access Controls (MAC) are appropriate for multilevel secure military applications, Discretionary Access Controls (DAC) are often perceived as meeting the security processing needs of industry and civilian government. This paper argues that reliance on DAC as the principal method of access control is unfounded and inappropriate for many commercial and civilian government organizations. The paper describes a type of non-discretionary access control - role-based access control (RBAC) - that is more central to the secure processing needs of non-military systems than DAC.

• The paper presents RBAC as a structured alternative to discretionary access control, emphasizing centralized role management over user discretion.
• It formalizes access policies with set-based rules for role assignment, authorization, and transaction control, ensuring integrity and least privilege.
• The study highlights RBAC's practical benefits, including reduced administrative burden and effective support for complex security policies in non-military environments.

Role-Based Access Control: An Analytical Perspective

Overview

The paper "Role-Based Access Controls" by David F. Ferraiolo and D. Richard Kuhn, presented at the 15th National Computer Security Conference in 1992, critiques the prevailing reliance on Discretionary Access Control (DAC) mechanisms in non-military commercial and civilian governmental systems. The authors propose Role-Based Access Control (RBAC) as a more suitable and structured alternative, emphasizing the limitations of DAC and the importance of RBAC's administrative capabilities.

Context and Limitations of Existing Models

Historically, security models such as the Trusted Computer System Evaluation Criteria (TCSEC) have been designed with military applications in mind. The TCSEC, widely recognized in the U.S., introduces two main types of access controls: Discretionary Access Control (DAC) and Mandatory Access Control (MAC). While DAC has been deemed appropriate for commercial and civilian government security needs, and MAC is reserved for multilevel secure military systems, Ferraiolo and Kuhn argue that DAC inadequately addresses the control requirements of many civilian environments.

DAC and Its Shortcomings

DAC allows users to grant or revoke access to resources they "own," a pattern that may not fit organizational structures where information ownership is often corporate, rather than individual. Hence, DAC's discretionary nature can lead to inconsistencies and security vulnerabilities, as access decisions are left up to individual users without centralized oversight.

RBAC: A Structured Alternative

RBAC centers access control on the roles assigned to users within an organization, aligning access with job functions rather than user discretion. Each role corresponds to a set of permissions, which are centrally managed and aligned with organizational policies. Unlike DAC, where access can be transferred at the user's discretion, RBAC ensures that permissions tied to roles cannot be arbitrarily reassigned by users, thus providing a more robust integrity control.

Key Aspects of RBAC

1. Central Administration and Policy Enforcement: RBAC allows centralized management of roles and permissions, which simplifies administrative tasks, especially in organizations with high personnel turnover.
2. Support for Complex Security Policies: By defining roles according to organizational needs, RBAC can enforce nuanced security policies dynamically. This is particularly useful in contexts where operations require strict separation of duties, such as financial transactions in banking and clinical management in healthcare.
3. Integrity and Least Privilege: RBAC inherently supports the principle of least privilege, ensuring users have only the permissions necessary to perform their tasks. This minimizes the risk of privilege misuse or fraud.

Formal Description and Rules

The paper formalizes RBAC using set-based notation:

• AR(s): Active role for subject s.
• RA(s): Authorized roles for subject s.
• TA(r): Transactions authorized for role r.

The following rules are stipulated:

1. Role Assignment: Ensures a subject executes a transaction only if they have an active role.
2. Role Authorization: Validates that a subject's active role is among their authorized roles.
3. Transaction Authorization: Confirms a subject can only execute transactions authorized for their active role.

These rules ensure robust access control, preventing unqualified execution of transactions and unauthorized information flow.

Practical Implications

The practical adoption of RBAC brings significant benefits. It aligns well with operational workflows in various sectors, as evidenced by existing implementations in database systems and cryptographic modules (referenced works of Baldwin, Nash, and Poland). RBAC's administrative ease can notably reduce the complexity and overhead associated with managing large-scale information systems.

Speculative Discussion on Future Directions

Future developments in RBAC could involve more refined models incorporating context-sensitive access control, where decisions are influenced by additional environmental factors (e.g., location, time of access). In the field of AI, hybrid models combining RBAC with attribute-based access controls (ABAC) may evolve, offering adaptive and granular access policies to meet the dynamic needs of modern computing environments.

Conclusion

The paper by Ferraiolo and Kuhn makes a compelling case for RBAC as a more aligned and effective access control mechanism for non-military applications compared to DAC. By centralizing and structuring access permissions around organizational roles, RBAC not only enhances security but also streamlines administrative processes. This foundational work sets the stage for further innovations and adaptations in access control methodologies, essential for securing increasingly complex and distributed information systems.