The modern concept of APIs is more than 20 years old, and since then, APIs have become very popular and commonly used.
Today, APIs have grown large in numbers and have become a necessary part of software development. As per RapidAPI’s Developer Survey and Insights report, in the year 2020, 61% of developers reported using more APIs compared to the previous year. In addition, 71% are expected to use even more APIs in coming years.
Traditional DAST scanners are not that much capable to cover APIs completely. They can cover only a small portion. If an application’s front end does not interact with all API endpoints, traditional DAST scanners are more likely to miss them. It is, therefore, crucial to adopt an extensive API testing strategy.
API security is nothing but building APIs in such a way that attackers can’t exploit them and their vulnerabilities. API security is a key component of modern web application security. Commonly found vulnerabilities in APIs include broken authentication and authorization, lack of rate-limiting, and code injection. There are the best API security testing tools available in the market, including APIsec and Postman. Before knowing how to do API security testing, we need to understand that a vulnerable API could lead to:

- Unauthorized Access
- Data Leakage
- Sanctioning Fuzzy Input
- Injection Vulnerabilities
- Parameter Tampering
API Security Attacks and Trends
- A Salt Labs report reveals an extraordinary surge in attacks on APIs in the first half of 2021. Monthly API call rates increased by 141%, whereas malicious traffic increased by a gigantic 348%.
- 94% of respondents of the Salt Security Survey have experienced an API security breach incident in 2020.
Common Security Problems Found in Production APIs

- Salt Labs states that 62% of organizations have very basic or no strategy in place for API security which is concerning.
- In the year 2019, Airtel API was found leaking the information of their customers by using their numbers. It affected around 325 million users of Airtel.
- In 2019, a bug CVE-2019-5786 was found in the File Reader API. Almost, all major browsers were impacted by this, and hackers exploited it wildly to target Chrome users.
Top 10 API Security Issues
API Security Testing Methods
Input Fuzzing

Command Injection

Parameter Tampering

Test Unhandled HTTP Methods

API Security Best Practices
Some of the most common ways by which you can ensure API security include:
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1. Access Control
Authenticating API traffic using OAuth and JWT allows you to set access control rules to specific API resources.
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2. Encryption
Encrypting data using TLS is standard practice for API security. Decrypting or modifying data would require users to provide a valid signature.
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3. Vulnerability Assessment
It is important to run penetration tests on your APIs so that vulnerabilities are caught at the right time.
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4. Quotas and Throttling for APIs
If quotas for API are defined regarding how many times it can be called and tracking its usage over time, it can help you keep them secured. It can reduce the chances of DoS attacks.
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5. Partner With an API Testing Services Provider
Partner with a provider that can place a strong API security testing process, like QASource. The professional QA engineers at QASource can implement automated testing techniques to increase the efficiency and comprehension of API tests.

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