We have discussed the benefits of Role Based Access Control and outlined a method to rationalize user applications as a first, critical step in the roles definition process. Today’s discussion provides an overview of how to define the roles that grant users entitlements to applications and systems. This process includes the use of role mining tools, the definition of role structures, and the development of a role catalog.
Role Definition Step 1: Leverage Mining Tools and Methods
Once application rationalization has been completed, we can safely assume that our applications are aligned to our organizational roles. At this point, we can formally define our user roles by collecting and refining this information to derive a role model. These roles will be closely tied to your existing job positions, which will map to a defined set of applications and access levels. For organizations with a large number of employees and applications, we recommend using software to assist in managing the role definition effort. Some products to help you accomplish this task are:
· CA’s Eurekify Sage
· Sun’s Role Manager
· SailPoint
These tools analyze existing user access patterns across multiple systems and applications to define access privileges and associate those privileges to roles.
Role Definition Step 2: Determine Role Catalog Structure
A Role Catalog is a database designed to help manage the list of roles and information about each role, and most RBAC products have one. Role Catalogs are an important tool because they associate each role with permissions, policies (e.g., separation of duty), and even other roles depending on the type of role service levels being managed.
Current RBAC standards define four role service levels, and we recommend using these standards to define your role catalog structure. The rules are:
- Level 1 - Flat RBAC – establishes and maintains many-to-many relationships among user-role and permission-role assignments.
- Level 2 – Hierarchical RBAC – extends coverage to include user-role and inherited roles (role-to-role) assignments.
- Level 3 – Constrained RBAC – applies separation of duty constraints and policies, both static and dynamic.
- Level 4 – Symmetrical RBAC – provides a permission role review and auditing interface for role administrators.
Source: The NIST Model for Role-based Access Control
Role Definition Step 3: Define a Hierarchical Role Structure and Role Inheritance Model
The number of users, the types of roles and your security requirements will help you determine which RBAC Level to implement. If you are planning for a Level 2 – Hierarchical or higher, then you will also need to consider defining the role relationships or role inheritance model.
Inheritance allows for roles within the hierarchy to leverage the privileges of the lower roles. This can significantly reduce the number of roles you need to create. A typical hierarchy starts with three tiers of Roles:
– Tier 1: Permission Roles
These are the lowest tier of role that can be granted. Permission roles are typically defined and managed by the network file system, database or directory administrators. Examples include: Create, Delete, Modify, View Files, Data records or Directory Attributes.
– Tier 2: Technical or Application Roles
Technical Roles can inherit the existing lower tier Permission Roles. Technical roles are generally controlled by Application and or Directory Administrators based on how the application manages user or groups. The benefit of the inheritance is you directly assign a single Role to the user, but the user inherits multiple lower tier permissions.
– Tier 3: Organizational Roles
Organizational Roles inherit the lower tier roles and are directly assigned to the user. Organizational roles are typically defined by Operations and Management as the Job Title or Job Function.
NOTE: Most organizations will find that three tiers for inheritance are sufficient. While you can add as many tiers as you need, extra tiers tend to have an exponential affect on the number of roles and the relationships you must manage.
Role Definition Step 4: Define Role Administration processes
Once you have your roles and the role relationships defined, you can begin the process of determine the best administration process for you role catalogue. The administration process should indentify:
· Role Catalog Administrator
· Administrative process
o New role requests and approval process
o New role creation process
o Role Requests and approvals
o Security and Separation of Duty override approval process
o Auditing and Reporting process
For medium to large sized organizations, you may find the implementation of an Identity Management System (IDM) to be the best way to administer roles. Most IDM product vendors have also included RBAC in their product suite, which makes the overall system much more tightly integrated.
Enterprise-level RBAC provides a framework to manage access rights efficiently and enforces security/access policies across different user groups more effectively than previous administration models. Analyzing, developing and maintain your Role Based Access Control system may seem difficult at first, but the operational and cost benefits for those that are successful are significant. And those that administer their RBAC system with and Identity Management Framework enjoy the true benefits of process automation. With RBAC in place you are able to rapidly address changes in organizational structure and business processes while managing information security risks and access controls.