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API security testing entails testing the endpoints of an application program interface (API) for security, and reliability, to ensure that it complies with an organization’s best practices.

What is the origin of API security testing?

The modern concept of APIs was born in 2000, when Salesforce launched its web-based sales automation API in an “internet as a service” model. Since then, APIs have exploded in popularity and prevalence.

Today, APIs continue to grow in number, serving as a fundamental part of modern software development across industries. In 2020, 61% of developers reported using more APIs than in the previous year. And 71% anticipate using even more APIs in coming years.

This increase in API usage is due in part to the standards that organizations have developed to encourage API adoption. OpenAPI and AsyncAPI provide the specifications for machine-readable files that help describe, produce, consume, and visualize RESTful services.

How does API security testing work?

API security testing helps ensure that basic security requirements have been met, including the conditions of user access, encryption, and authentication concerns. The idea behind API scanning is to craft inputs to coax bugs and undefined behavior out of an API, essentially mimicking the actions and attack vectors of would-be hackers.

API security testing begins by defining the API to be tested. Testers provide information on inputs and outputs of the API, using a variety of specification formats including OpenAPI v2 / v3, Postman Collections, and HAR files. API security tests use this information to construct fuzzed input tailored to the input the API expects.

The output of API security testing is a report of any vulnerabilities or bugs found while fuzzing the API. This could include findings such as SQL and OS command injections, authorization/authentication bypasses, path traversal issues, and OWASP Top 10 API vulnerabilities such as broken auth, security misconfiguration, and data exposure. 

Why is API security testing important?

APIs are the heart of many applications, providing developers with powerful interfaces to the services an organization has to offer. Ensuring that APIs are conformant to published specifications and are resilient to bad and potentially malicious input is critical to an organization’s overall security.

Traditional dynamic application security testing (DAST) scanners cannot cover APIs completely; they cover only a small portion of them. If an organization’s front end does not interact with all API endpoints, traditional DAST scanners will miss them. It is therefore essential to adopt a modern, dynamic API security testing strategy that targets issues in all of an API’s endpoints.

API Security Testing | Synopsys

What are the benefits of using API security testing?

At the most basic level, API security testing helps identify and prevent vulnerabilities and their associated potential organizational risk. 

Specifically, API security testing is fine-tuned to both the API being tested and an organization’s overall strategy and best practices. API scanners work at a deeper level, examining the APIs that power single-page web apps, IoT devices, or mobile apps. By understanding what an API expects as input, API scanners can intelligently fuzz data to uncover hidden bugs.

API security testing tools also help enforce the correctness of an API, scanning the business logic of an API rather than just the input validation provided by the front end.

API security testing can also help identify where an API diverges from published API specifications. For example, if a specific endpoint should respond with a particular HTTP status but another is detected during a scan, the testers will alert the appropriate stakeholder. This helps ensure that the developers who leverage the APIs have an experience consistent with published specifications.

How to test API security?

Synopsys Seeker® IAST is an interactive app security testing tool that tests APIs such as OpenAPI, GraphQL, and more. It automatically detects and surfaces all the API routes and endpoints during normal development and QA tests and works well in DevOps CI/CD. It provides real-time alerts as well as visual data flow maps of all the inbound and outbound calls, along with detailed line-of-code insights that help ensure timely developer remediation. The continuous testing and verification provided by Seeker allows DevSecOps teams to react and respond quickly with the least friction to their workflow.

Synopsys WhiteHat Dynamic is a software-as-a-service (SaaS) DAST solution that allows your business to quickly deploy a scalable web security program. No matter how many websites you have or how often they change, WhiteHat Dynamic can scale to meet any demand. It provides security and development teams with fast, accurate, and continuous vulnerability assessments of applications in QA and production, applying the same techniques hackers use to find weaknesses so that you can remediate them before the bad guys exploit them. 

With open API integration, WhiteHat Dynamic can be integrated with popular bug-tracking systems; security information and event management solutions; governance, risk, and compliance products; and web application firewalls (WAFs).

Explore how to build security into DevOps