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Top 9 OSS API Security Tools

A guide on the 9 best OSS API security tools that protect sensitive data, infrastructure, and business logic from unauthorized access, data theft, and other attacks.

Wiz Experts Team
6 minutes read

API security: A quick review

Recent years have brought a surge in API-based attacks, which are considered to be some of the most damaging cyberattacks, according to Gartner. Luckily, OSS API security tools are an effective way to protect sensitive data, infrastructure, and business logic from unauthorized access, data theft, and other attacks.

APIs are the gateways to communication and data exchange between users, apps, and servers. Because they are often designed to be easy to locate, carry sensitive data, and contain information that can help hackers understand your business logic, APIs are prime targets for cybercriminals. Application programming interface (API) security is the practice of safeguarding APIs from threats and potential vulnerabilities.

Pro tip

Modern apps are powered by hundreds of APIs (estimates put it at an average of 613 APIs per enterprise) that facilitate communication and data transfer between users and apps, as well as between different microservices in an app. If not properly secured, that’s a potential 613 entry points for API attacks that could result in data theft, compliance violations, and financial and reputational damage.

So what does it mean to secure an API? API security includes measures such as:

  • API authentication and authorization, which control user access to and actions within APIs

  • Data encryption, which protects data transmitted by APIs using cryptographic hashes 

  • Rate limiting, which caps the number of API requests to prevent DDOS attacks and API abuse

  • Input validation, which verifies user input to prevent injection and cross-site scripting attacks

Robust API security also involves implementing best practices and deploying API security tools to monitor and test APIs.

Choosing the right API security tool: 7 must-ask questions 

When choosing an OSS API security solution, verify that the tool offers these capabilities: 

  1. API discovery: Can the tool scan your enterprise’s entire cloud environments to discover and inventory all APIs and API endpoints? 

  2. Integration: Does it integrate easily into your development environment, CI/CD pipelines, and existing security solutions without disrupting your workflows?

  3. Testing: Can it run dynamic application security testing (DAST) scans of your APIs to detect runtime bugs and security gaps that can be revealed only when clients and servers interact?

  4. Runtime protection: Can it conduct comprehensive scans and provide actionable insights to help you address common API security vulnerabilities like broken authentication, misconfigured API endpoints, and others listed in the OWASP Top 10 API Security Risks?

  5. Compliance: Can the API security tool facilitate compliance with regional and industry-specific regulatory standards such as GDPR, PCI DSS, and HIPAA?

  6. Scalability: As your app and API needs grow, can the tool handle increasingly large and complex workloads without slowing down your DevSecOps processes?

  7. Maintenance and support: Are security and performance updates released regularly to fix issues in the tool? Does the solution have an active community to offer you support should you need help utilizing it?

Best OSS API security solutions

Below are our top picks for OSS API security tools, along with their key features, pros, and cons.

1. APIsec|Scan

APIsec|Scan is an API security testing solution that conducts non-intrusive scans to discover common vulnerabilities in APIs.

Features

  • Integrates into multiple software development pipelines, including Git and Bitbucket

  • Supports manual and scheduled tests

  • Uncovers dependency and runtime vulnerabilities using different scanning techniques such as API software composition analysis, static application security testing, and dynamic application security testing

Pros

  • Enables automatic API discovery and scanning

  • Detects common vulnerabilities like suboptimal attribute-based access control (ABAC) and role-based access control (RBAC) configurations

Cons

  • Limits API scans to un-authenticated tests, which may miss important vulnerabilities

  • May generate false negative results, requiring you to integrate another API security tool for comprehensive protection

2. Burp Suite

Figure 1: Burp Suite dashboard (Source: Burp Suite)

Burp Suite Community Edition is primarily a dynamic application security testing tool, but it has extended functionality to enable API endpoint protection. 

Features

  • Has a crawler for discovering OpenAPI documents that automatically identify exposed API endpoints

  • Detects SQL injection, cross-site scripting (XSS), and CSRF attacks

Pros

  • Capabilities can be extended with various add-ons

  • Has a strong community of professionals providing support

Cons

  • Ideal for manual security testing only

  • Is mostly a learning, rather than a testing toolkit

3. Curity Identity Server (Community Edition)

Curity Identity Server Community Edition is a popular OAuth server for managing API security posture. It provides modern scanning capabilities to authenticate API endpoints, web apps, and mobile apps. 

Features

  • Enables API access management

  • Supports various authentication mechanisms, including OpenID Connect, OAuth 2.0, and custom authentication

  • Supplies API tokens to minimize the risk of XSS and CSRF attacks

Pros 

  • Provides single sign-on and customized claims to streamline user authentication and authorization

  • Offers logging and user management to track user and system actions

Cons

4. Hurl

Figure 3: The Hurl dashboard (Source: Hurl)

Hurl is a command-line tool for testing HTTP API requests and validating responses. It allows you to conduct complex assertion tests to validate HTTP responses using headers, status codes, and response bodies. 

Features

  • Uses a straightforward syntax written in plain text format

  • Works with REST, GraphQL, and SOAP APIs, ensuring comprehensive coverage of various HTML content

Pros 

  • Supports GitHub Actions and Bitbucket, enabling easy integration into CI/CD pipelines for automated API testing

  • Is lightweight and easy to deploy, adding little to no performance overhead to your stack

Cons

  • Conducts functional tests mainly; not optimized for security testing

  • Requires a steep learning curve

5. Kong Insomnia

Figure 4: The Kong Insomnia dashboard (Source: Insomnia)

Kong Insomnia’s REST Client is a solution designed for building, testing, interacting with, and debugging various APIs. 

Features

  • Supports multiple testing environments including Git, cloud, and local development environments

  • Supports several advanced scripting capabilities for testing, validating, and manipulating HTTP requests and responses to detect common API vulnerabilities

Pros 

  • Is a lightweight tool with 350+ open-source plugins that can be added or removed as the need arises

  • Supports REST, GraphQL, gRPC, and SOAP APIs and analyzes HTTP and WebSocket requests, enabling comprehensive debugging and testing

Cons

  • Lacks support for comprehensive API security testing

6. Rest Assured

Rest Assured is an API security testing solution designed for testing RESTful APIs written in Java. It’s a well-maintained project with an active community of developers and security engineers.

Features

  • Handles various authentication mechanisms, making it ideal for securing API endpoints

  • Supports JSON and XML formats for flexible data transfer during API testing 

  • Handles multiple request types, such as POST, GET, DELETE, PUT, PATCH, etc., which it uses to verify API performance 

Pros

  • Fluent API that simplifies API testing

  • Supplies cross-site request forgery (CSRF) tokens to minimize the risk of CSRF attacks on APIs

Cons

  • Cannot conduct vulnerability scans to detect injection, cross-site scripting, or CSRF attacks

  • Can only scan Java-based REST APIs

7. SoapUI

Figure 6: The SOAP UI dashboard (Source: SoapUI)

SOAP UI is an API testing solution designed to provide a spectrum of capabilities, including API load, functional, mocking, and security tests.

Features

  • Supports multiple API protocols such as REST, SOAP/WSDL, GraphQL, and JMS

  • Offers drag-and-drop features for designing custom test scenarios

Pros

  • Has a user-friendly GUI

  • Integrates easily with CI/CD pipelines to automate security testing across the SDLC

  • Has a vibrant open-source community of developers and security experts

Cons

  • Can be very resource intensive

  • Provides support for basic security testing only; users may need to integrate advanced API security tools to ensure comprehensive protection

8. Swagger UI

Figure 7: The Swagger UI dashboard (Source: Swagger)

Swagger UI is a popular real-time API behavior testing solution. It provides a visual interface that empowers development teams to scan and interact with REST API resources without requiring access to implementation logic.

Features

  • Facilitates API authentication via authentication tokens and credentials

  • Enables real-time scans of API requests, including POST, GET, PUT, and DELETE 

Pros 

  • Has a dependency-free architecture that enables integration with various development environments

  • Enables complete access to Swagger UI’s source code to allow for seamless customization

Cons

  • Not primarily an API security testing solution

  • Only tests REST APIs

9. ZAP

Figure 8: The ZAP dashboard (Source: ZAP)

Zed Attack Proxy (ZAP) is a web application vulnerability scanner that uses fuzzing, active, and passive scanning techniques to conduct DAST-like API scans. Though it is primarily a DAST tool, it offers various add-ons for API scanning, including OpenAPI, SOAP, GraphQL, and import URLs add-ons.

Features 

  • Handles various API authentication techniques such as basic auth, OAuth, and JWT 

  • Has proxies for crawling APIs, intercepting API requests, and delivering malicious payloads to API endpoints

Pros

  • Conducts real-time scans

  • Supports scan-policy customization

Cons 

  • May give false negative results, requiring you to manually conduct penetration tests to discover missed vulnerabilities

  • Is complex to deploy and use

Bolster API security with Wiz

The tools we’ve covered have wide-ranging benefits, but they also have one limitation in common: Each covers only some aspects of API security, requiring you to integrate a complicated amalgam of OSS tools for comprehensive coverage. Enter the Wiz Dynamic Scanner.

Example of Wiz’s Security Graph visualizing two APIs effectively exposed to the internet with exposed secrets

Wiz's Dynamic Scanner supports API security by providing several advanced features that help discover, assess, and secure APIs in cloud environments, such as: 

  1. Continuous API Discovery: It automatically discovers and inventories APIs exposed to the internet across cloud environments, providing visibility into both managed and unmanaged APIs.

  2. External Exposure Analysis: The scanner validates externally exposed APIs, analyzing ports, protocols, and HTTP status codes to give an attacker's perspective.

  3. Unauthenticated API Detection: It identifies unauthenticated APIs that may be exposing secrets or sensitive data, allowing security teams to quickly address these high-priority issues.

  4. Context-Aware Risk Assessment: Wiz provides a comprehensive view of the API's security posture by analyzing the full cloud stack, including the hosting resource, associated vulnerabilities, and potential for lateral movement.

  5. Automated Alerting: The system includes out-of-the-box controls that trigger automated alerts and remediation workflows when non-compliant APIs are detected.

  6. Custom Policy Enforcement: Users can create custom controls to ensure organization-specific policies are enforced for API security.

By offering these capabilities, the Wiz Dynamic Scanner helps organizations proactively identify and address API security risks, reducing their attack surface and enhancing their overall cloud security posture.

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