5 Security Tests Every API Should Pass

API security breaches at major companies cost billions annually, with 91% of organizations experiencing an API security incident in the past year. These five essential security tests can help you avoid becoming another statistic.

1. Authentication & Authorization Testing: The First Line of Defense

Strong authentication and authorization mechanisms form the backbone of API security, preventing unauthorized access to sensitive endpoints and data.

Major vulnerabilities arise from weak authentication schemes, improper implementation of role-based access control (RBAC), and flawed token validation.

To properly test authentication and authorization:

• Test JWT validation thoroughly, including token expiration, signature verification, and claims validation
• Verify OAuth flows by checking token exchange, scope validation, and proper refresh mechanisms
• Test RBAC by attempting to access resources with different user roles and permissions
• Ensure API keys are properly validated and cannot be bypassed with header manipulation

Tools like OWASP ZAP, Burp Suite, and Postman help automate these security tests with predefined security scans and custom test scripts.

2. Input Validation & SQL Injection Testing: Preventing Data Manipulation

SQL injection remains one of the most common attack vectors for APIs, allowing attackers to execute unauthorized database queries or commands.

The root cause typically stems from direct concatenation of user input into SQL queries and inadequate input sanitization.

To test for SQL injection vulnerabilities:

• Send payloads with SQL syntax like ' OR '1'='1, UNION SELECT, and DROP TABLE users;
• Test all input parameters, including query parameters, headers, and request bodies
• Verify handling of special characters, extreme input lengths, and unexpected data types
• Check responses for SQL errors that might reveal database structure