PBAC vs. RBAC: What’s the Difference?

Last updated on March 18, 2025

PBAC and RBAC are two common approaches to authorization. Each of these two access control models is a common part of Identity and Access Management (IAM) in organizations around the globe. But which one best fits your company? Here’s the difference between PBAC vs. RBAC and which one is better for your unique business needs.

PBAC vs. RBAC: Key Differences and Best Use Cases Explained

Key Differences:

• Authorization Criteria:
  • RBAC (Role-Based Access Control): Assigns permissions based on predefined roles within an organization. Each role has a specific set of permissions, and users are granted access according to their assigned roles.
  • PBAC (Policy-Based Access Control): Determines access based on dynamic policies that can consider various factors such as user attributes, resource types, and environmental conditions. This allows for more granular and context-aware access decisions.
    
• Flexibility and Scalability:
  • RBAC: Offers simplicity but can become cumbersome in large organizations due to role proliferation, leading to challenges in management and potential security risks.​
    PBAC: Provides greater flexibility by allowing policies to be adjusted without overhauling the entire access control system, making it more scalable and adaptable to complex environments.

Best Use Cases:

• RBAC: Suitable for organizations with straightforward access requirements where roles and permissions are relatively static and well-defined.
• PBAC: Ideal for organizations that require fine-grained access control, need to comply with dynamic regulatory requirements, or operate in environments where access decisions must consider multiple contextual factors.

What is RBAC?

Role-Based Access Control (RBAC) is a type of access control that determines what a user can or cannot do based on the roles assigned to them.

RBAC is simple. First, you create a role. Then, you assign a set of permissions to that role. Finally, you assign the role to one or more users. For example, you can create a role called Text Editor, give it permission to edit text files, and assign it to Bob, Alice, and Margaret, all three of whom are copywriters in your company.

What Are the Drawbacks of RBAC?

Unfortunately, Role-Based Access Control comes with many disadvantages. The most important drawbacks of RBAC are:

• Requires manual management
• May lead to a privilege creep
• Scaling leads to role explosion
• Authorizes users based on roles only

Requires Manual Management

Businesses are not static. They are constantly changing. Companies hire new employees and change the permissions of old ones. Such a dynamic environment poses a challenge to a role-based access control system and administrators who have to manually add, remove, and update a user’s access rights. Let’s get back to our example. What if Bob left your company, Alice should no longer have permission to edit text files but should still be able to read them, and Margaret needs new permission to delete text files? Your administrators have to make all these changes manually, one by one, by editing the roles of each user and creating or editing permissions accordingly.

May Lead to a Privilege Creep

Unfortunately, a high number of roles and employees in an RBAC system can lead to a privilege creep where users have more privileges than necessary. A privilege creep is doubly dangerous for your organization. Firstly, a user with excessive permissions can misuse their access rights to access resources they are not supposed to see. An angry employee that leaves your company may maliciously want to change, copy, or delete your data to get back at you. Excessive permissions you are not even aware of would not help. Then, even if your employee has no malicious intent and does not access assets they are not authorized to access, should a hacker manage to gain unauthorized access to this employee’s account, the hacker would be able to do more harm than usual.

Scaling Leads to Role Explosion

Today’s workforce is dynamic and has to operate on strict security regulations. Access control has to be easy to scale and maintain. RBAC authorizes access to users based on their roles. So, if one employee accesses five applications, with two roles in each, you need to define and maintain 10 roles just for that one employee. It is not hard to imagine that if you have hundreds of employees, you can end up with thousands of roles really fast. Indeed, the RBAC model can easily lead to role explosion, a chaotic quagmire of roles and permissions that is hard to maintain and scale.

Authorizes Users Based on Roles Only

Last but not least, RBAC authorizes users and restricts access based only on the assigned user roles. Role-Based Access Control does not allow the creation of access rights and permissions based on time, location, device, and other security control information. These limited capabilities of RBAC make it a limited solution.

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What is PBAC?

Policy-Based Access Control (PBAC) is a type of access control that dynamically determines what a user can or cannot do based on policies and rules.

PBAC is just a model, meaning it is not limited to a particular implementation. For example, Extensible Access Control Markup Language (XACML) fully supports PBAC. Another standard that implements PBAC is ALFA (XACML).

PBAC is similar to Attribute-Based Access Control (ABAC). Indeed, policies are built of attributes, so what is the difference between ABAC and PBAC? In short, ABAC must be written in Extensible Access Control Markup Language (XACML). In contrast, PBAC is not reliant on XACML.

PBAC vs. RBAC: What’s the Difference?

While both RBAC and PBAC are types of access control, RBAC determines access rights and privileges based on roles assigned to the user, while PBAC is based on policies.

PBAC	RBAC
Policy-Based Access Control	Role-Based Access Control
Access rights and permissions are based on policies.	Access rights and permissions are based on roles.
Flexible and easily scalable	Difficult to scale; scaling leads to role explosion
Compliant with regulations such as GDPR	May not abide by regulations and security requirements
Dynamic and automated	Needs manual management
High visibility into authorization controls reduces privilege creep risks	Privilege creep risk
Authorization based on device, location, time, and other security controls possible	Limited to role-based authorization, does not take into account other security controls, e.g., user IP or time of the day
Fine-grained and dynamic	Coarse-grained and static with no way to define temporary access rights

The Role-Based Access Control (RBAC) model is flawed. For that reason, many organizations decided to adopt a different approach to access control. Compared to RBAC, Policy-Based Access Control (PBAC) is resilient and easier to maintain. PBAC offers full transparency of your employees, devices, and regulations. Further, PBAC is flexible and adaptable, which better fits the regulations and requirements of a modern enterprise.

Potential Cyberattacks Targeting RBAC and PBAC Systems

Understanding the vulnerabilities associated with each access control model is crucial for implementing effective security measures.

• RBAC Vulnerabilities:
  • Role Explosion: The proliferation of roles can lead to mismanagement and inadvertent permission grants.​
  • Privilege Creep: Users accumulating permissions over time without revocation can result in excessive access rights.​
• PBAC Vulnerabilities:
  • Policy Misconfiguration: Complex policies may lead to errors in access control decisions if not properly managed.​
  • Performance Overhead: Evaluating dynamic policies in real time can introduce latency, affecting system performance, thus requiring a scalable and highly efficient system.

Enhancing Access Control Security with Multi-Factor Authentication (MFA)

Integrating Multi-Factor Authentication (MFA) into both RBAC and PBAC systems can significantly enhance security by adding an additional layer of verification.​

• PBAC With MFA: Incorporating MFA into PBAC systems allows for dynamic authentication requirements based on policy conditions, such as requiring stronger authentication methods for access to sensitive resources or during high-risk scenarios.
• RBAC With MFA: Combining RBAC with MFA ensures that even if role-based credentials are compromised, unauthorized access is still mitigated through additional authentication steps.​

PBAC vs. RBAC in Multi-Factor Authentication (MFA)

It would not be a stretch to say that, symbolically, PBAC is to Authorization what Multi-Factor Authentication (MFA) is to Authentication. Here’s a cool idea: What if you could combine PBAC with MFA? Well, Context-Based Access Control (CBAC) is already a thing, and Adaptive Authentication, or Risk-Based Authentication, as it is often called, can significantly bolster your cyber defenses even if, and especially if, you are already using MFA.

Let’s take Rublon as an example of a Multi-Factor Authentication (MFA) solution that also uses Policy-Based Adaptive Authentication. Rublon Policies introduce additional security controls that can determine access rights and authentication mechanics of logins. In short, administrators create access policies and assign them to applications. One policy can be assigned to one or more applications. Changes in the policy instantly apply to all applications that use this policy, which eliminates the need to dabble in the settings of every user and application separately.

Now, when a user logs in to an integrated application, the settings in the policy are applied to that application. These might be, for example, the ability to add the device as trusted or bypass MFA altogether, given the IP address falls within a given range. Administrators can also decide which authentication methods will be available to users who log in to that application. Of course, all of this is done either before, after, or during user authentication. But the benefits of such an approach to Adaptive Authentication are aplenty.

PBAC vs. RBAC: Conclusion

PBAC and RBAC are two popular access control models. Policy-Based Access Control improves the faulty RBAC and employs fine-grained, dynamic, flexible, and easily scalable authorization controls compliant with modern security regulations. You can use Adaptive Authentication that follows the logic of PBAC to strengthen your MFA.

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