Attribute Based Access Control Explained

If you’re in charge of securing your organization’s resources, you know how important access control is. It’s the process of deciding who can access what and do what with it. But as your organization grows and your resources become more varied and complex, you might find that traditional access control models like access control lists (ACLs) and role-based access control (RBAC) are not enough to meet your needs. That’s where attribute-based access control (ABAC) comes in handy.

What is ABAC?

Attribute-based access control (ABAC) is a way of granting or denying access based on attributes. The words “attributes” are characteristics or values that describe security principals, resources, actions, and the environment. From this definition, we also have some other terms that you probably are not familiar with. Security principals, for example, are the users or entities that request access to resources, which refer to the assets or objects that security principals want to access. Actions are what security principals want to do with resources and the environment is the context or situation of the access request.

With ABAC, you can define flexible and dynamic access policies based on any attribute that matters to your business logic which will be explained in the next section.

How ABAC works

ABAC is based on the idea that any access decision can be expressed as a logical statement that checks attributes. There are four kinds of attributes:

Subject attributes

These are the attributes of the user who wants to access a resource, such as their identity, role, group membership, department, security clearance, etc. For example, Alice is a subject with the attributes name = Alice, role = manager, department = sales, security clearance = high, etc

Resource attributes

These are the attributes of the resource that the user wants to access, such as its name, type, owner, location, classification level, etc. For example, “Document1” is a resource with the attributes name = Document1, type = pdf, owner = Bob, creation date = 01/01/2021, classification level = confidential, tag = ProjectX, etc.

Action attributes

These are the attributes of the action that the user wants to perform on the resource, such as read, write, edit, delete, etc. They can be used to express access control policies based on the actions that are allowed or denied for a user or a resource. For example, an ABAC policy could state that managers can approve transactions up to their approval limit, where the action attributes are approved and limited.

Environment attributes

These are the characteristics or values of the broader context of each access request, such as the time, location, device, protocol, encryption, risk, or behavior of the user. They can be used to express access control policies based on the environmental factors that are relevant or required for a user or a resource. For example, an ABAC policy could state that a user can access a file only from a specific IP address range or during business hours, where the environment attributes are IP address and time.

Consideration for implementing ABAC

The benefits, costs, and risks of adopting ABAC in an organization are some of the aspects that should be considered before implementation.

Benefits

ABAC allows for the widest range of users to access the greatest amount of resources without requiring any input from the admins. This is especially useful for organizations that need to safely share information across different domains, such as federal agencies or enterprises. ABAC also enables granular yet flexible policy-making, compatibility with new users, and stringent security and privacy through its use of attributes

Reduced administrative burden & increased flexibility and scalability

As mentioned above, ABAC doesn’t require constant input from the admin, thus allowing better flexibility and scalability. ABAC also simplifies the process of granting access to new users, based on their attributes, rather than having to assign them specific roles or permissions. Additionally, ABAC can leverage automation and technology to streamline the access control process and reduce human errors and costs. By reducing administrative burden, ABAC can enhance operational efficiency, improve user satisfaction, and advance equity and inclusion

Enhanced security and compliance

By using attributes of the user, resource, environment, and action, ABAC can enhance security and compliance with more context-aware and dynamic authorization. This way, ABAC can effectively close security gaps and honor employee privacy, while efficiently following regulatory compliance requirements. Moreover, ABAC can leverage policy-based access control to simplify authorization and enforce granular and consistent rules across the organization. Due to these reasons, ABAC is suitable to changing business needs and regulations with the attributes that have specific business meaning.

Costs

Initial investment in infrastructure and resources

ABAC may require more upfront investment in defining attributes, policies, and rules for a large and diverse organization with many data sources and users. Besides, ABAC may require integration or migration from legacy systems that use different access control models.

Policy development and maintenance

The regulatory and business requirements for data security and compliance also needs to be taken into consideration. ABAC may offer more value in terms of meeting the demands of data protection laws, industry standards, and customer expectations for data privacy and security.

Performance optimization.

ABAC may require techniques to measure and optimize the performance of the ABAC system, such as caching, indexing, pruning, partitioning, etc. Performance metrics should indicate the quality and timeliness of changes to attributes and policies, as well as the overall system and end-to-end performance. It implies that the cost of ABAC may depend on the techniques and tools used to measure and optimize the performance of the ABAC system. An enterprise should be aware of the trade-offs between investing in performance optimization and achieving the desired level of security and efficiency for access control.

Risks

Interoperability issues

Interoperability issues may occur due to incompatibility with other systems or standards that are involved in access control. For example, the ABAC system may not be able to communicate or exchange attribute data with other identity providers, directories, databases, etc., or the ABAC system may not be able to support different access control models (e.g. MAC, DAC, or RBAC). Consequently, it may result in access denial, data inconsistency, policy conflicts, or user frustration which we are going to explain later on. Thus, ABAC systems should be designed and enforced with proper interoperability standards, protocols, and mechanisms allowing hybrid or co-existence scenarios with other access control models.

Attribute inconsistency or compromise

Attribute inconsistency or compromise is a risk that may arise from implementing ABAC, which means that attackers may try to bypass ABAC policies by maliciously forging or manipulating the attributes listed on them. This may result in unintended access to protected resources or violation of security and compliance requirements.

Policy conflicts or errors

Policy conflicts and errors are another risk that may arise from implementing ABAC, which means that the access control policies may contain inconsistencies, ambiguities, or mistakes that affect their correctness and effectiveness. For example, policies may grant or deny access to the same user or resource under different conditions, or policies may be missing or incomplete for certain scenarios. Policy conflicts and errors may result in unauthorized access, data leakage, compliance violations, or user dissatisfaction.

User resistance or confusion

User resistance and confusion are another risk that may happen when you use ABAC, which means that the people who use the ABAC system may not get or like the rules or choices that are based on attributes. For example, people may not know what attributes are used to decide their access rights, or people may not agree with the access rights given or taken away from them or others.

User resistance and confusion may cause unhappiness, problems, arguments, or breaking the rules. To avoid this risk, ABAC systems should be made and used with proper user teaching, talking, and listening mechanisms. Users should also be part of the rule making and checking process to make sure their voice and agreement.

Conclusion

ABAC is a powerful and flexible way of controlling access to your organization’s resources based on attributes. It can help you improve information sharing, reduce administrative burden, and enhance security and compliance. However, it also comes with some costs and risks that you need to consider and mitigate.

To implement ABAC properly, you need to define, assign, create, implement, and monitor attributes and policies that match your business logic and needs. You also need to ensure interoperability, integrity, correctness, and acceptance of your ABAC system.