Guide to Java authentication and authorization

In modern software development, authorization ensures that only privileged, or authorized, users have access to specific resources or functionalities in an application. Proper authorization mechanisms enable granular control over user permissions and fine-grained access restrictions. It helps protect sensitive data, prevent unauthorized actions, safeguard user privacy, maintain regulatory compliance, and preserve the overall trust and reliability of your software.

Authorization technologies have seen significant changes and advancements in recent years. Traditional approaches like role-based access control (RBAC) have been supplemented with attribute-based access control (ABAC) to allow for more fine-grained and context-aware authorization decisions. Technologies like OAuth and OpenID Connect have also become popular for secure authentication and delegated authorization, enabling seamless integration with third-party services. Such advancements have resulted in more flexible, scalable, and secure authorization solutions.

This article provides an overview of the evolving landscape of authorization and its relevance in meeting the changing needs of software development to help you choose the best authorization framework for your Java application. It covers:

• Traditional and modern authorization techniques such as RBAC, ABAC, and more;
• Popular authorization frameworks for Java, including Spring Security, Apache Shiro, and JAAS;
• The role of authorization in microservices; and
• Emerging technologies in authorization and how authorization will evolve to meet the changing needs of software development.

Traditional vs. modern authorization techniques

First, let's explore the evolution from traditional authorization techniques, like RBAC and ABAC, to more modern approaches, like policy-based access control (PBAC).

Role-based access control

RBAC focuses on the roles assigned to users within an application. It provides a structured approach to access control by defining roles, permissions, and user-role assignments.

For instance, a document management system that uses the RBAC approach might result in three roles: admin, editor, and viewer. The admin role can perform all operations on documents, the editor role can create and modify documents, and the viewer role can only view documents. Users are assigned a role based on their responsibilities within the organization.

RBAC simplifies access control by managing permissions at the role level rather than individually for each user. This reduces administrative overhead.

However, RBAC may not provide the level of granularity required for complex access control scenarios that demand more than just role-level access management. In these cases, ABAC comes in handy.

Attribute-based access control

In ABAC, access control decisions are made by evaluating various attributes associated with users, resources, and environmental conditions using attributes, policies, and an evaluation engine.

An ABAC approach to the document management system mentioned previously would mean that users are assigned attributes such as employee department, document sensitivity level, and employee clearance level. For instance, a junior HR associate with a lower clearance level from the HR department will only be allowed to view certain HR-related documents, whereas an employee with a higher clearance level can access confidential documents, and so on.

ABAC offers more fine-grained control over access compared to RBAC by

allowing applications to implement complex authorization rules based on attributes. However, the complexity of defining and managing attribute-based policies can be a limitation.

Policy-based access control

PBAC is a modern authorization technique that makes access control decisions based on defined policies rather than predefined roles or attributes.

PBAC revolves around the concept of policies—rules or statements that dictate access control decisions based on various factors such as user attributes, resource properties, environmental conditions, relationships, time, location and more. These policies are centrally managed to ensure consistency and ease of administration across different applications.

To return to our example of a document management system, the PBAC approach would involves defining policies such as the following:

• Policy 1: Users in the finance department can access financial reports during business hours.
• Policy 2: Users in the sales department can access customer-related documents based on their sales region.

The benefit of this approach is even clearer if you imagine this as a cloud-based storage service that handles data from multiple organizations. Using a PBAC approach, the service can define policies that govern access based on various attributes such as user roles, organization memberships, and data classifications.

As the service scales and new organizations onboard, it can easily update policies to accommodate the needs of each organization without extensive code modifications.

This scalability allows the service to handle a growing number of users and resources while maintaining a robust and adaptable access control framework. It also offers adaptability to evolving business needs or regulatory requirements.

PBAC allows for more complex and fine-grained policies that can incorporate various attributes, roles, time, location, and contextual information to make access control decisions. Separating policy management from the application logic enables efficient scalability without significant performance impact. Additionally, the ease of updating policies or attributes reduces the maintenance overhead as changes can be implemented centrally and propagated across the system.

PBAC also supports compliance management and auditing as policies can be defined to align with security and privacy regulations while auditing mechanisms track and monitor access control decisions.

Authorization frameworks for Java

Next, let's explore three of the most popular authorization frameworks for building Java applications: Spring Security, Apache Shiro, and Java Authentication and Authorization Service (JAAS).

Spring Security

Spring Security is a widely used authorization framework for Java applications.

It offers robust authentication mechanisms such as form-based authentication, HTTP Basic/Digest authentication, and more. It supports various authorization approaches, including role-based access control (RBAC) and expression-based access control, which can be used to implement fine-grained access control rules that align with ABAC and PBAC techniques.

Spring Security provides a flexible configuration model that allows developers to define security rules and policies. It supports both XML- and Java-based configuration approaches, making it easy to customize and adapt to specific application requirements.

Lastly, Spring Security seamlessly integrates with other components of the Spring framework, enabling developers to leverage its features within a Spring application. It integrates well with Spring Boot, Spring Data, and other Spring projects, providing a cohesive security solution.

Apache Shiro

Apache Shiro is a powerful and lightweight authorization framework that focuses on providing a simple and intuitive security API to simplify the implementation of security features in Java applications.

Apache Shiro provides authentication support for various mechanisms, including HTTP Basic authentication, Lightweight Directory Access Protocol (LDAP), and more. It offers flexible authorization mechanisms such as RBAC and wildcard-based permission models. Developers can define their own authorization strategies, implement custom permission checks, and integrate external policy decision points to enforce ABAC and PBAC principles.

It also provides session management capabilities, allowing developers to manage user sessions securely. Shiro includes utilities for cryptographic operations, such as password hashing, encryption, and decryption, and it simplifies the implementation of secure data handling within an application.

Apache Shiro can be integrated into various types of applications, including web, command line, and desktop applications.

JAAS

JAAS is a standard Java API for authentication and authorization. It is a part of the Java SE platform and allows applications to implement pluggable authentication modules (login modules) for user authentication.

JAAS allows applications to support different authentication mechanisms by implementing custom login modules. This flexibility enables applications to authenticate users against various backends, such as LDAP, databases, or custom user repositories.

It provides a framework for implementing fine-grained authorization policies through the use of common classes like JAAS Subjects, Principals, and Credentials. It supports the Java Security Manager, which allows applications to define access control policies at a granular level.

JAAS enables developers to configure authentication and authorization settings through configuration files or programmatic ways. This flexibility allows for easy customization and adaptation to different application requirements.

Lastly, JAAS integrates well with the Java EE platform, allowing Java EE applications to leverage its authentication and authorization capabilities. It can be used in conjunction with Java EE containers.

Comparison of authorization frameworks

Let's do a brief comparison of these three authorization frameworks based on their key features, security, ease of use, and community support.

Spring Security

• Extensive set of features, including authentication, authorization, and out-of-the-box role-based access control capability
• Very secure with features to protect against attacks
• Easy to use with a declarative configuration style
• Large and active community with resources to help developers

Apache Shiro

• Less extensive set of features than Spring Security but still includes authentication, authorization, and role-based access control
• Very secure with features to protect against attacks
• Easy to use with a number of configuration options available
• Smaller community than Spring Security but also has resources to help developers

JAAS

• Basic features, including authentication and authorization
• Less secure than other two solutions but still includes features to protect against attacks
• More difficult to use than Spring Security or Apache Shiro as it requires a programmatic configuration style
• Small community with fewer resources to help developers

Overall, all three frameworks offer core security features, but Spring Security stands out for its extensive feature set, strong security measures, and wide community support. Apache Shiro focuses on simplicity and ease of use, while JAAS is a standard Java API but may have fewer community resources available.

However, keep in mind that the framework you choose will depend on the requirements and priorities of your application. It's best to carefully evaluate each framework to your needs.

Best practices for choosing an authorization framework for a Java application

Begin by clearly understanding your application's authentication and authorization needs. Consider factors such as the type of application (web, RESTful API, enterprise system), support for secure authentication protocols like OAuth or Security Assertion Markup Language (SAML), the complexity of access control rules, and integration requirements with other frameworks or systems. Experiment with the frameworks of choice and choose the one that best meets your application and organization requirements.

Also keep in mind whether your application falls under specific compliance requirements, for instance,[PCI-DSS. If yes, ensure that the authorization framework you choose aligns with those standards. Look for any security audits or certifications the framework has undergone to validate its security measures.

Lastly, if you're considering a solution outside of the three mentioned above, use the four criteria above (core features, security, ease of use, and community support) to evaluate whether the solution meets your needs.

Authorization and microservices

Now that you have an idea of the popular authentication frameworks for building your Java application, let's understand the role of authorization in microservices.

A microservices architecture segregates services based on domain or business functionality. Authorization plays a critical role in a microservices architecture by ensuring that only authorized users and services can access the appropriate resources and functionalities of each microservice.

For example, in an e-commerce application, authorization is essential when a user wants to place an order. The order management microservice should only be accessible to authenticated users with the necessary permissions. The authorization mechanism verifies the user's identity, checks their permissions, and allows access only if the user meets the defined authorization criteria.

Authorization can also be applied at a granular level within each microservice. For instance, the product catalog microservice may have different authorization rules based on user roles or attributes. Some products may be restricted to certain user groups, such as premium members or administrators. The authorization mechanism evaluates these rules and grants or denies access accordingly.

By integrating authorization into a microservices architecture, organizations can ensure that access to resources and functionalities is controlled and secure. It provides a layered security approach where each microservice can define its own access control policies. This allows for fine-grained control over who can access what, reducing the risk of unauthorized access and potential security breaches.

Challenges of authorization in a microservices architecture

However, authorization in a microservices architecture introduces several challenges, including complexity, scalability, and security in multitenancy environments.

The complexity of authorization increases in a microservices architecture due to the distributed nature of the system. Multiple microservices communicating and collaborating makes it intricate to manage and enforce authorization policies across the entire ecosystem. Each microservice may have its own set of permissions, roles, and access control rules, making it challenging to ensure consistency and coherence in the overall authorization strategy.

As the number of microservices grows, managing and scaling the authorization mechanisms becomes more complex. Each microservice potentially has its own authorization rules and policies, so ensuring efficient and coordinated access control across the system can become difficult. Additionally, the increased traffic and requests in a distributed environment can strain the authorization infrastructure, and careful design and implementation is required to maintain performance and responsiveness.

Lastly, in multitenancy scenarios, multiple tenants or clients may share the same infrastructure and resources. Ensuring secure isolation between tenant data and preventing unauthorized access or data leakage is paramount. To handle the complexities of multitenancy, authorization mechanisms need to be designed to enforce strict access controls to protect sensitive data and maintain privacy and confidentiality.

Implementing authorization using best practices can help overcome these challenges, though.

Best practices for implementing authorization in a microservices architecture

Firstly, organizations implementing authorization in a microservices architecture should use centralized and scalable authorization management solutions. Such a solution should provide a unified view of authorization policies across the microservices ecosystem with the ability to monitor and audit the microservices for consistent and manageable access control. Additionally, leveraging technologies like API gateways can help centralize authentication and authorization functions to simplify the complexity and improve scalability.

One such solution is Cerbos PDP, an open source authorization solution designed to help developers implement fine-grained, policy-based access control. Cerbos PDP provides a unified view of authorization policies across the microservices ecosystem with the ability to monitor and audit the microservices for consistent and manageable access control.

Using OAuth, OIDC, or a similar identity provider can further simplify the authentication setup by offloading the responsibility of user authentication and authorization to a trusted third-party service. This eliminates the need for developers to implement and maintain complex authentication mechanisms, which reduces development time and effort.

As mentioned earlier in this article, using modern authorization techniques such as PBAC can enhance fine-grained access control and scalability. Cerbos is built around this principle, allowing developers to define policies that govern access based on various attributes such as user roles, organization memberships, and data classifications. However, if your need for an access control level is not complex enough, at least consider ABAC or a hybrid approach between RBAC and ABAC. Such a strategy lets you benefit from the simplicity of role-based control while incorporating attribute-based flexibility.

Leveraging technologies like API gateways can help centralize authentication and authorization functions to simplify the complexity and improve scalability. Cerbos can be integrated with API gateways to provide a comprehensive and centralized solution for managing access control in a microservices architecture."

Future of authorization

Authorization technologies are continuously evolving to address the growing complexity and security challenges in modern software systems. These emerging technologies offer innovative approaches to access control and authentication to enhance flexibility, scalability, and adaptability.

Some current emerging authorization technologies to take note of include zero trust architecture (ZTA), decentralized identity/self-sovereign identity, and adaptive security architecture (ASA).

Security models such as ZTA assume that no user or device can be trusted by default. This means that all access to a system or resource must be verified, regardless of whether the user is inside or outside the organization's network. This security model has high potential to get deployed across several industries because it validates or verifies everything without placing trust in any attributes. Security models like continuous authentication might become the new norm, using methods such as biometrics or behavioral analytics.

The future of authorization holds great promise for shaping the landscape of software development. As applications become more complex and distributed, the need for robust and adaptable access control mechanisms becomes paramount. The evolution of authorization will continue to impact software development to improve security, scalability, and flexibility.

Conclusion

In an ever-evolving threat landscape, organizations need to stay updated on the latest security trends and adopt the most appropriate authorization solutions to protect their data and systems. This article provided you with an overview of the landscape of authorization to help you choose the best authorization framework for your Java application.

You learned how traditional authorization techniques like RBAC and ABAC compare with a newer approach, such as PBAC. You got an overview and comparison of three popular authorization frameworks for Java as well as tips for how to make sure you choose one that's right for your Java app. You also explore the role of authorization in microservices and how to avoid some common challenges of authorization in a microservices architecture. Lastly, you got a glimpse of emerging technologies and how authorization is continuing to evolve.

From everything you've learned in this article, what's the one thing that will make the biggest difference if you apply it to your next project?