Automated API Security Testing

API security testing is the process of testing the endpoints of an application program interface (API) and identifying vulnerabilities and security flaws. API facilitates data exchange between applications, and thus, security testing is crucial because if a hacker breaks API security, he can access sensitive and confidential data.

There are various forms of API security tests. While Static Analysis and Software Composition Analysis look for vulnerabilities in libraries and patterns in your code, Dynamic Analysis searches for potential vulnerabilities by sending active requests to the API and interpreting the response received.

Here's a step-by-step checklist for performing API Security Testing:

• Determine the scope to define and list the objectives, scope, desired results, tools, and security solutions to be used. 
• Scan your APIs to identify all the endpoints, dependencies, and security controls. This will let you outline a baseline context for attack simulations. 
• Perform Static Analysis and Software Composition Analysis, which identify library vulnerabilities and code patterns. Further, perform Dynamic Analysis which identifies vulnerabilities by sending requests to the API and interpreting the response received.
• Prepare a detailed report and include the identified vulnerabilities, security gaps, and recommendations to fix them. Lastly, retest and revalidate the APIs to ensure that security recommendations have been completely implemented.

Usually, API security testing is employed in the production environment. However, there have been efforts to integrate API security testing into the early stages of SDLC.

Though the frequency of API security testing may vary with factors like the necessity of the API, the number of changes in the API, and the severity of risk associated with the API, the testing should be performed regularly. 

Conducting API security testing is essential to ensure your organization meets the necessary standards. We recommend evaluating new updates, features, or upgrades as they occur; once every year should also be sufficient. Suppose specific legal requirements are in place. In that case, this may need to be conducted more often- perhaps monthly or quarterly - but rest assured our recommended protocols will help keep you compliant and secure.

API (Application Programming Interface) is the interface that connects two or more applications to facilitate data sharing. 

API Security Testing is a methodology that checks an API's endpoints to ensure that APIs meet basic security expectations. The testing technique examines the conditions of user access, authentication rules, and encryption conditions, along with the pattern, behavior, execution, and security of the application. 

While testing an API, you should check the following:

• Accuracy of endpoint naming
• Data accuracy, type, validations, order, and completeness
• Response payload and headers
• Implementation of response timeout
• HTTP status codes
• No missing or duplicate functionality exists
• Schema validation
• Error codes in case API returns, and
• Authorization checks
• Non-functional testing: Performance and security testing

Yes, API Testing can be and should be automated.

Manual API security testing provides many benefits; leveraging human insight allows testers to create customized test cases that assess threats and vulnerabilities. However, with its complex nature and associated time constraints in assessing APIs thoroughly or ensuring complete error elimination, manual testing alone may not be enough for full coverage.

Automated API security testing is the silver lining here. Being automatic, it is faster and completes the test in just a few minutes. It also reduces the chances of human error and detects security issues that scanners can't.

• Injection
  It happens when the application accepts input from an untrusted source and processes it. This further enables malicious attackers to execute faulty code or steal confidential data. API Injection threats include SQL, CRLF, XML, LDAP, and OS commands.

• Broken User Authentication
  It happens when the authentication procedures are not configured accurately. This will let malicious and unauthorized users with knowledge of the correct username and password access the API, further resulting in security breaches such as data theft, stolen credentials, privilege escalation, session hacks, etc.

• Data Exposure
  It happens when the application accidentally discloses more information than required to the user. The API response might reveal confidential information like login credentials or banking information, which a malicious user could use to conduct financial misappropriation or identity theft. The attackers might blackmail the user to pay a ransom in exchange for the security of this data, or they might sell it on the dark web.  

• Mass Assignment
  It happens when a web application accepts user-generated inputs and automatically assigns variables to it in the application code without verification or filters. 
  A malicious user could exploit this security flaw by inserting unsecured data into the application's input fields, resulting in sensitive data exposure and unauthorized execution.

• Security Misconfiguration
  This happens when security settings are not configured properly, for instance, ad-hoc configurations, misconfigured HTTP headers, insecure default configurations, verbose error messages, and permissive CORS. Misconfiguration leaves the security setting open to attacks.   
  Other API vulnerabilities include Improper Assets Management, Cross-site scripting, Insufficient Logging & Monitoring, Broken Object Level Authorization, and Broken Function Level Authorization.

Initial Setup of API Testing

APIs are complex in nature. API security testing involves a lot of parameters to send data requests and enter data values through API endpoints.

With each new parameter, the magnitude and quantity of possible combinations increase exponentially. Manually evaluating these parameter combinations is a time-consuming and challenging task.

Validating Parameters

Security testers find it challenging to invalidate the parameters received via various API requests.

Additionally, they must ensure that all parameter data fits within the designated value range and length restriction, uses the correct numerical data type, and passes other validation criteria.

Denial of Service Attacks

APIs being vulnerable to Denial of Service (DoS) attacks are susceptible to the system being overloaded or crashing. Checking for DoS attacks requires specialized tools, skills, and techniques.

Tracking System Integration​

Integrating the API testing system with the data tracking system is another challenging task in API security testing. This integration is essential to monitor the API performance and ensure appropriate responses on whether a call is working properly. 

Lack of Visibility

Since third-party applications use APIs, a lack of visibility exists in the API ecosystem. Hence, it becomes challenging for security testers to monitor and look for unauthorized access and usage.