API Security testing or Application Programming Interface security testing helps in identifying and preventing the vulnerabilities in your APIs. API security is of utmost importance because it is critical for an organization to identify vulnerabilities and secure data from any kind of risk.

1. Fuzz Testing: It is a black-box testing method that aims at discovering bugs by injecting malformed code. We conduct Fuzz Testing by using a combination of the following for an attack –

• Numbers – The attack comprises integers, floats, signed, or unsigned numbers. For integers zero, negative, and positive numbers are used.
• Chars – command-line inputs and URLs are used for this attack.
• Metadata – Here the attack contains the user-input text.
• Binary sequences – The API is attacked using random binary sequences

2. Parameter Tampering: In Parameter Tampering, the parameters sent in API requests are manipulated by using backend validation errors. This can be done in two ways –

• Modifying input fields in a web form.
• Modifying query parameters in API requests.

3. Command Injection: An injection flaw occurs in an API when a web application passes information from an HTTP request to another command, database command,  like a system call, or an external service. It is carried out in the following ways –

• OS commands in API requests: Our testers at Precise Testing Solution have good knowledge of different OS and commands, so can carry out this test well.
• SQL in API Parameters : SQL is a common vulnerability that occurs when unsanitized data from an API request is used in a database command.

4. Testing for Unhandled HTTP methods : A server that does not support HTTP methods should show errors. But in the case of APIs that are vulnerable, we make a HEAD request to your API endpoint that requires authentication.