Open Policy Agent (OPA) security is becoming a must for cloud defense. An open-source tool, it serves as a policy engine for cloud-native environments. It is designed to facilitate the management of policies implemented across software systems, which are becoming more complex as cloud technologies progress.
As container orchestration platforms like Kubernetes gain traction, organizations need to update their security solutions to keep up with more advanced risks and changes in compliance requirements. Akamai, for example, offered a POC and Open Policy Agent solution to address a recently discovered Kubernetes bug that can enable the takeover of Windows nodes.
OPA is hardly just a buzzword in the cybersecurity industry. It is a real solution that organizations need to be getting acquainted with, especially given the complex security considerations of using infrastructure-as-code (IaC) tools. It enables policy-as-code while consolidating the enforcement of security policies and isolating policy decisions from the IaC code.
IaC Workflow Integration
One of the benefits of using IaC tools is their built-in integrations for Open Policy Agent. The leading infrastructure-as-code tools are usually designed with native support for OPA. Terraform, for example, supports the setting and evaluation of OPA policies. AWS CloudFormation supports hooks (written in Python or Java) that can be deployed to deliver policy decision requests to OPA.
Various plugins and modules allow organizations to integrate OPA into IaC workflows. The Kafka Authorizer plugin, for example, enables data source integration guided by OPA and comes with sample policies. The Gatekeeper Conftest plugin, which is intended for Kubernetes, converts input objects into forms that are compatible with OPA Gatekeeper policies. Additionally, the VS Code plugin facilitates the development, testing, debugging, and analysis of OPA policies in VS Code.
Integrating OPA with IaC workflows is also possible through sidecar deployment. This approach entails the deployment of OPA as a sidecar container during IaC provisioning. After deployment, the IaC tool communicates with the OPA (as a sidecar) to assess policies during or prior to infrastructure creation.
Additionally, OPA security is made easier with IaC tools through API integration. There are IaC tools that provide APIs to support OPA interaction with them. This integration enables OPA to access infrastructure definitions, which also makes it possible to pass policy decisions in accordance with OPA-retrieved data.
Moreover, infrastructure-as-code services can improve OPA security through third-party tools. These “external” tools are specifically created to serve as a bridge that fills the gap between OPA and IaC, efficiently transmitting data from IaC configurations to OPA for policy evaluation. The decision made by OPA is then passed to the IaC tool, which may greenlight deployment if there are no OPA policies violated, or automatically prevent the deployment if security issues are detected.
Treating Infrastructure as Data
IaC tools inherently treat infrastructure as data, which is an advantage when it comes to OPA security. OPA leverages this dynamic by accessing and evaluating infrastructure definitions right within the IaC code. This makes OPA’s security decisions focused on the resources being provisioned. All security decisions are expectedly data-driven, but when it comes to OPA and IaC tools, these decisions are specific and targeted.
OPA analyzes the data it retrieves from IaC tools in great detail, enabling fine-grained security policy enforcement. It supports the precise implementation of security policies by referencing attributes in the IaC code and targeting security controls intended for specific resources and scenarios. IaC handles the defining of attributes while OPA is responsible for enforcing the policy as part of the provisioning process.
On the other hand, treating infrastructure as data makes it easy to integrate automatic security evaluation into the CI/CD pipeline. Organizations can place OPA within the pipeline to assess IaC code according to security policies and spot misconfigurations and other security issues before any provisioning happens. This is an efficient way to examine the IaC code, as it significantly reduces human involvement, thereby minimizing errors and ensuring consistent security policy enforcement across all IaC configurations.
Infrastructure as data also simplifies policy updates or the implementation of policy as code, because security policies are set and modified directly in the OPA configuration files. IaC tools routinely reference these security policies, which means that any update made is automatically enforced as the IaC tools undertake security checks. It simplifies security policy updating and prevents instances of errors or the failure to reflect security policy updates.
Declarative Nature of Policy Enforcement
IaC tools generally use declarative configuration, which emphasizes the achievement of a desired state instead of creating commands or instructions. Declarative and imperative approaches have their respective pros and cons, but when it comes to infrastructure-as-code, the former usually has an edge especially when dealing with sophisticated infrastructure.
OPA security similarly uses the declarative approach in enforcing security policies, making it compatible if not perfectly matched with IaC tools. This convenient alignment in expressing security requirements makes it considerably easier and simpler to address security needs. They create a strong combination, as OPA policies directly reference IaC attributes or resource properties in security enforcement.
OPA and IaC tools use declarative languages that force organizations to focus on what the desired states are, rather than how to achieve such states. This removes any need to reconcile declarative with imperative configurations and vice versa. IaC configuration with Terraform, for example, is written in HCL, which is a declarative language similar to Rego, the language used for OPA policies. The use of these shared languages results in simpler and more efficient configurations.
Moreover, the use of declarative languages provides the advantage of being able to clearly separate concerns. Since they use the same approaches in stating desired outcomes or states, security concerns can be clearly assigned to OPA, distinct from the infrastructure concerns in IaC tools. OPA handles the centralized management of security policies, which are then referenced across the IaC configurations. OPA policies are easily distinguishable from IaC definitions, making it easy to update security policies and maintain the code at the same time.
Notably, the distinction between security policy and infrastructure configuration concerns supports modularity, which simplifies policy creation and code maintenance. It allows different teams with different areas of expertise to focus on what they do while collaborating to build a secure and well-maintained infrastructure.
Powerful Synergy
The use of IaC tools and OPA security provides organizations a systematic way of enforcing security policies through a synergistic way of writing infrastructure definitions and centralizing security policies. This helps organizations make the most of the benefits of implementing infrastructure-as-code and Open Policy Agent for security. It supports the integration of OPA into IaC workflows, granular security enforcement, automatic security checks, the separation of security and infrastructure concerns, and enhanced code maintainability.
