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Understanding gRPC Security:
How StackHawk Keeps Your
APIs Protected

brian erickson

Brian Erickson|April 11, 2023

Discover the importance of gRPC security testing and learn how StackHawk's dynamic application security testing tools can help you protect your gRPC APIs from potential threats. Boost your API security with Custom Test Data and Custom Test Scripting.

As modern applications become more complex and distributed, gRPC is rapidly gaining traction as a powerful and efficient framework for building microservices and connecting various components across distributed computing platforms. But with all the exciting benefits gRPC brings to the table, it's essential to keep security top of mind. That's where StackHawk comes in, offering a robust solution to secure your gRPC services and APIs.

In this blog post, we'll dive into what makes gRPC unique, explore its common use cases, and compare it to other popular API technologies like OpenAPI and GraphQL. We'll also discuss the importance of testing gRPC services for security vulnerabilities and how StackHawk's dynamic application security testing (DAST) capabilities can help you ensure your gRPC APIs are both powerful and secure.

Join us as we navigate the exciting world of gRPC and discover how StackHawk can help you stay ahead of potential threats while building the next generation of API communication. And don't miss out on our special offer for production-level gRPC users who provide valuable feedback during our beta period!

What is gRPC?

gRPC is an open-source, high-performance framework that's gaining popularity for building microservices and distributed systems. It excels at service-to-service communication, as opposed to traditional APIs that often focus on service-to-client browser communication. Recognized for its speed and efficiency, gRPC enables seamless connections between mobile apps, backend services, and various components across distributed computing platforms.

How does gRPC differ from OpenAPI or GraphQL?

gRPC, OpenAPI, and GraphQL are all distinct technologies for building and consuming APIs, each with its strengths and ideal use cases.

gRPC utilizes the Protocol Buffers data serialization format and supports both synchronous and asynchronous communication. Ideal for building internal, microservices-based architectures, gRPC places a strong emphasis on performance and scalability, enabling efficient service-to-service communication.

OpenAPI (formerly known as Swagger) is an open-source framework for building and documenting RESTful APIs. It uses a JSON or YAML file to define the API's endpoints, parameters, and responses, making it particularly suitable for creating and documenting public-facing APIs. OpenAPI boasts a large ecosystem of tools for generating code, documentation, and testing, fostering ease of use and collaboration.

GraphQL is a query language and runtime designed for constructing flexible, high-performance APIs. Unlike RESTful APIs, which have fixed endpoints and response structures, GraphQL empowers clients to request precisely the data they need and nothing more, all from a single endpoint. This approach leads to more efficient data retrieval and an improved developer experience, making GraphQL a popular choice for building public-facing APIs.

Benefits of gRPC

gRPC boasts several advantages, such as:

  • High performance due to serialized protocol buffers

  • Cross-platform support for various programming languages

  • Language-independence, with generated code for client-server communication

  • Streamlined development for complex distributed systems

  • Interoperability with HTTP/2-based systems

  • Secure communication using Transport Layer Security (TLS)

  • Scalability with built-in load balancing

Common gRPC use cases

  1. Microservices architectures: gRPC streamlines inter-service communication in modern, distributed applications. With efficient data serialization using Protocol Buffers, support for multiple programming languages, and built-in load balancing, gRPC is ideal for building scalable and maintainable microservices-based applications.

  2. Real-time applications: gRPC's support for bi-directional streaming enables the rapid exchange of data between client and server, making it perfect for real-time applications. This capability is invaluable for chat apps, live notifications, real-time data streaming, online gaming, and other use cases where low latency and continuous data exchange are crucial.

  3. Mobile apps: Due to limited bandwidth and resources on mobile devices, gRPC's lightweight and efficient communication is a significant advantage. Its compact binary serialization format, Protocol Buffers, reduces the payload size, resulting in faster data transfer and reduced network usage. This makes gRPC an excellent choice for mobile applications where performance and responsiveness are essential.

Despite the many benefits and diverse use cases gRPC supports, it's essential not to overlook the importance of security testing for gRPC (and all your APIs!).

Why test gRPC Services?

While gRPC communication typically happens inside the firewall, it's crucial to maintain strict security practices to protect your APIs. Securing every part of your system ensures a more comprehensive approach to overall security.

gRPC services, like REST, SOAP and GraphQL APIs, are susceptible to attacks from the OWASP Top 10, so don't assume they're immune. In particular, gRPC applications can be exploited through:

  • Broken Access Control

  • Cryptographic Failures

  • Injection

  • Insecure Design

  • Security Misconfiguration

  • Sensitive Data Exposure

  • Insecure Deserialization

Secure your gRPC services with StackHawk

Traditional DAST tools may not support gRPC, but StackHawk has you covered. It's designed to work with gRPC services over HTTP/2 using protocol buffers to generate requests and parse responses. This allows StackHawk to effectively target and check gRPC application endpoints, identifying potential security issues.

With StackHawk, you can leverage Custom Test Data and Custom Test Scripting to conduct comprehensive security testing on your gRPC APIs. Custom Test Data allows you to specify input values for your gRPC API requests, which ensures that your security testing covers the wide range of potential data interactions your application might encounter. This helps identify vulnerabilities that could arise due to unexpected or malicious input.

Custom Test Scripting enables you to create tailor-made test scenarios for your gRPC APIs. You can write scripts that define specific sequences of requests and responses, mimicking real-world user interactions and potential attack patterns. By customizing your testing approach, you can better identify security vulnerabilities and edge cases unique to your application's architecture and business logic.

Combining Custom Test Data and Custom Test Scripting with StackHawk's dynamic application security testing capabilities, you can thoroughly assess the security of your gRPC APIs, ensuring that they are robust and resilient against potential threats.

Automated API security testing in CICD

Have a gRPC Application in Production? Earn swag for your feedback!

If you're already using gRPC in production, we'd love to hear from you. Reach out to give us your feedback. During the beta period, we're offering a StackHawk Swag Pack (or $100 Gift Card) to those who test production-level gRPC applications as a thank you for your valuable input!

To get started, scan your gRPC application using our getting started guide and reach out to with your feedback!

Brian Erickson is Sr. Product Manager at StackHawk

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Brian Erickson  |  April 11, 2023

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