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API Security Testing – Identifying API Security Risks

API security testing identifies leaky APIs and attacks surfaces that expose sensitive data. Use Parasoft’s tools to address security risks.

What Is API Security Testing?

Security issues and security risks for web applications, IoT devices, and other endpoints can lead to massive data breaches. API security testing can be used to mitigate this as it involves understanding complex API behaviors and interactions to identify vulnerabilities that could expose sensitive data. One such example where security testing is key relates to API requests: an action of sending or retrieving data.

But the four major areas to directly test APIs include:

  1. Functionality
  2. Performance
  3. Reliability
  4. Security

Naturally, security testing puts a heavy focus on eliminating API vulnerabilities before APIs get pushed to production software applications.

Digital background with coding on the right to display API security testing.

Using API testing tools such as Parasoft SOAtest, incorporating automated continuous testing, and other strategies all aid cybersecurity measures. After all, why address data exposure after it happens if you can protect the sensitive data in the first place?

Let’s learn more about best practices, challenges, and key features of API security testing. This page also covers how to automate certain parts of application security, API relationships with application security testing, and how Parasoft API Testing Platform can best help prevent an API-based data breach.

Benefits of API Security Testing

APIs, or application programming interfaces, use function sets to interact with external components, microservices, or operating systems and access data. So, API security testing works best when security tests can be incorporated as part of developer functional testing. Testers can use benchmarks that all APIs must meet along with different types of testing. This includes static and dynamic tests, manual testing, automated tests, and more.

As with any element of cybersecurity, the benefits of API security testing are better, more secure APIs. Security scans and authentication measures won’t be enough to secure them. Going beyond basic security features can help prevent disruption in business operations.

Other benefits include:

  • Vulnerability identification and subsequent removal.
  • Reduction of testing and maintenance costs.
  • Testers do not need a UI to effectively do their jobs. They can fix something without it affecting the GUI.
  • Accounts for abuse and misuse cases.
  • Acceleration of testing cycles using automated tests.
  • Scalable API testing.
  • Technology agnostic for the most part with XML and JSON languages being the most commonly used.
  • Comprehensive API testing catches things that manual penetration tests and static and dynamic analysis tools often miss.
An example of mapping API Security Testing on the SDLC.

Regardless of the additional positives, the main focus of API security testing is finding and fixing vulnerabilities as early as possible. This includes in-house created code, third-party elements, or open source elements.

OWASP, the foundation focused on software security via open source projects, offers guidance and awareness around API security threat vectors. The OWASP top 10 most threatening vectors provide a baseline for where API security testing should begin.

Types of API Security Tests

There are many different ways to look for web application security risks. As with anything related to code, performing a variety of tests and keeping accurate, detailed test case records makes all the difference. Here are the main types of API security tests.

Dynamic API Security Tests

Active testing that simulates a real-world attack to find risks. These can surface from open source elements or from in-house code.

Penetration Testing

Occurs as the second test in a workflow where non-experts review an API to find vulnerabilities.

Functional Testing

Reviews API function against specific situations to ensure expected results.

Security Testing

Reviews how an API is insulated from exterior threats, access control design, encryption strategies, and authorization/authentication.

Fuzz Testing

Reviews how a system can handle excess “fuzz” (a large amount of data) to test for worst case situations.

Verb Fuzzing

Scans and enumerates APIs to find weaknesses and vulnerabilities in HTTP services by generating random input through HTTP methods.

Best Practices for API Security Testing

Following are 10 critical best practices for API security testing.

  • Test an API through its entire lifecycle.
  • Authenticate first. Then authorize to show who the user is and what permissions they have.
  • Always use HTTPS.
  • Your API Gateway should function as an enforcer that reviews parameters, content, authorization, and more.
  • Use service virtualization to conduct unlimited testing.
  • Use tokens for assigned identities.
  • Leverage rate throttling and limiting.
  • Encrypt data for added security.
  • Always audit third-party elements for security vulnerabilities.
  • Continuously monitor and identify threat vectors.
Digital background with the word “API” on it to showcase security vulnerabilities.

Examples of API Security Tests

Though there are many types of API security tests, there are specific ones more ubiquitous on their own than their parent categories.
Injection attacks occur when hostile inputs are put into an API such as an SQL injection or command injection. These attacks seek to gain privileges in order to gain access to data.

Other examples include something like a test for parameter tampering. This is when someone changes API request values to bypass what should be secure information. Checking related API elements on a web app or website via the browser console is an easy test to tell whether or not an API is secure.

But the most common example of an API security test might be input fuzzing. In this test, someone puts in random information into an API until something unexpected happens. This can cause error messages or total crashes thus revealing vulnerabilities in an application from outside attackers.

Common API Vulnerabilities

  • DDoS attacks
  • Broken access control
  • Pagination attacks
  • Components with vulnerable frameworks, libraries, and so on
  • Cross-site Scripting XSS
  • Inaccurate caching headers
  • Key exposure
  • Security misconfiguration
  • Poor API key generation
  • Insecure deserialization
  • Insufficient logging and monitoring
  • Inaccurate server security (HTTP methods)
  • Insecure endpoints

Why Parasoft

Diagram showing how Parasoft converts manual and automated UI tests into automated API tests.

Parasoft converts manual and automated UI tests into automated API tests.

There are many ways to enhance your software development workflow and ensure secure APIs. But automation is one of the few guaranteed measures that will deliver returns.

Whether it’s a CI/CD pipeline implementation, updating best practices for API security testing, or reacting to OWASP API changes, Parasoft tools offer agility, consistency, and versatility.

Start finding errors and reducing your risk of security breaches with options like Parasoft Virtualize integrate seamlessly to deliver specific behavior for your needed testing conditions.

Frequently Asked Questions

There are four main types of web APIs across various industries.

  • Internal APIs are private programs that usually connect data and systems within an enterprise such as HR or payroll.
  • Public/Open APIs can be used by any business or developer. These tend to require authorization and/or authentication and can include monetization.
  • Composite APIs combine multiple APIs to create interdependent operations to provide performance or speed improvements.
  • Partner APIs are licensed APIs that must be used in specific cases such as in business-to-business systems. An example would be Salesforce or AWS as they connect information to other systems. As such, security measures with partner APIs are critical.

Representational state transfer (REST) is an architecture for web APIs with client-server architecture, cacheability, statelessness, and layered systems.

Simple object access protocol (SOAP) is a protocol for web APIs that is programming style agnostic and extensible. These must feature message constructs, processing models, extensibility models, and protocol binding rules (HTTP).

A remote procedural call protocol (RPC) uses various parameters to produce one expected result. The two types, JSON-RPC and XML-RPC, merely indicate the type of encoding they use (XML vs. JSON).

  1. Small attack surface. API endpoints can be limited in number which means that there are fewer test requests.
  2. Non-universal support. Though many tools do support API testing, it is not universal by any means. Finding the right set of tools for your team is essential.
  3. API versioning. Even with automated testing, communication is critical, especially if different developers are working on the same code. Having detailed notes, test cases, and workflows will ensure that a data breach doesn’t occur due to miscommunication.
  4. Test schema updates. Modifying the parameters of a test takes time. Testing in alpha/beta environments can reduce the lag time between updates.
  5. API call sequencing. Like numbers, certain API calls should happen in specific orders. An example would be an online food order processing before a person has entered payment information.
  6. Business logic knowledge. Display policies, storage policies, rate limits, copyright policies, and more factor into API business logic. Keeping up-to-date on this information is key.
  7. Parameter validation. Testers must ensure that parameter data is correct regarding data type, length restrictions, value range, and more.
  8. Mass assignment. An active record pattern for web applications can be abused to let users change data components they should not be able to access such as passwords, admin status, or permissions.
  9. Injection flaws. Users gain access to the shell command, backend database, or OS. Hackers can use this vulnerability to alter, read, or delete data.