The Fundamentals of API Security Testing

By- Naman Rastogi

The first thing to understand about API security testing is that it is not a one-size-fits-all process. Testers must take into account the scope of the project, as well as the specific needs of developers and end-users. This article will provide you with some basic guidelines for an API security testing program. It will also outline some API security tests that you should consider including in your API testing process.

What is API Security Testing?

API security testing is a process that checks API functions for security vulnerabilities. These tests are intended to identify problems with the API's design, functionality, and implementation. API security testing is a proactive way to check the API for potential exploits.

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Tests To Include in API Security Testing

1) Test for Parameter Tampering

The API's parameter tampering test is a way to check any API calls that contain parameters for known attack patterns. The API security testing tool you use should provide warning alerts when it finds these types of vulnerability points.

Parameter tampering occurs because developers aren't properly securing the input data before it enters an API call from another application or web service. This gives attackers the ability to tamper with API input data. You can checkout this detailed guide on How to Perform Web Application Testing

Testing for API parameter tampering can include looking at all variables within API calls and checking whether they need to exist or not. In your tests, you'll also want to check how values are passed into API calls and whether or not they can be changed once data is passed in.

Also Read: No Halfway Deal In Security

2) Test for API Input Fuzzing

Input fuzzing is one of the most basic kinds of testing you can perform on an API. It occurs when attackers send API inputs that contain random or unexpected values. This test will show you whether the API can handle random data or not. It should do so without impeding its performance, but rather enhancing it.

The API security testing tool you use should allow for several different types of fuzzing:

●Data Format Fuzzing: An input format can be modified to see how the API responds when an invalid value is received.

●Range Fuzzing: Some APIs only accept certain numeric ranges from authorized users, such as credit card numbers and phone numbers. You should check whether your API functions properly under this type of condition.

The first thing to understand about API security testing is that it is not a one-size-fits-all process.Getastra

●Boundary Fuzzing: This type of fuzzing should be used to check for boundaries within the API itself. For example, checking if a string is between certain character lengths, determining whether it's possible to pass in an empty parameter value that will still produce valid results, etc.

Testing for API input fuzzing can also include randomizing parameters that are always required by the API function being tested (e.g., session IDs). If these values don't need to exist, hackers will be able to bypass any checks made by the developers who have implemented strict guidelines regarding API usage.

3) Test for Unhandled HTTP Methods

Another API security test you should consider is to check for unhandled API functions. Unhandled API methods are those that developers didn't code into the API. This happens either because they were unaware of their necessity or simply forgot about them.

Allowing access to these functions creates a vulnerability point in your API's functionality. Unfortunately, attackers can use these vulnerabilities as attack vectors. API security testing should search for unhandled API methods and alert you to their presence.

This API security testing method will help you determine how well the API performs under different input conditions without any malicious actors trying to tamper with it.

4) Test for API Injecting Attacks

A final API security test you should consider is to check for possible injection attacks. This type of vulnerability occurs when user-defined input data can be inserted into API calls as part of the API's scripting language.

Injecting attacks have been a long-time security threat for APIs. This is because they allow attackers to use any type of data that can be manipulated and inserted into an API call. They should ideally only allow what is provided by regular users or applications trying to access the API.

The API security testing process goes beyond just finding the presence of common API attack vectors like cross-site scripting (XSS), SQL injection, remote code execution, and much more. It also looks for other API features that can put your system at risk if they aren't properly secured with input validation defenses or strict API security features.

Final Thoughts

Though API security testing may seem daunting, it's a necessary step in securing your systems and data. As the saying goes, an ounce of prevention is worth a pound of cure! If you don't have time to do this yourself, you can always seek help from security experts. The costs are justified by the benefits. So, make sure to conduct API security testing if you haven't already!

Disclaimer: (This article is sponsored and include some commercial links)