API Security

API security encompasses practices and technologies used to protect Application Programming Interfaces from attacks and misuse, including authentication, authorization, rate limiting, and input validation.

API security focuses on protecting the interfaces that allow different software applications to communicate. As APIs become the backbone of modern applications, securing them is critical for overall security posture.

Key API security concerns: - Broken Authentication: Weak or missing authentication mechanisms - Broken Authorization: Users accessing data they shouldn't (BOLA/IDOR) - Excessive Data Exposure: APIs returning more data than needed - Rate Limiting: Missing protections against abuse - Injection Attacks: SQL, NoSQL, command injection via API inputs

Best practices: - Authentication: Use OAuth 2.0, API keys, or JWT tokens - Authorization: Implement proper access controls at the API level - Input Validation: Validate and sanitize all inputs - Rate Limiting: Protect against abuse and DDoS - Encryption: Use TLS for all API traffic - Logging: Log all API access for audit trails

OWASP API Security Top 10 is the standard reference for API vulnerabilities.

Why It Matters

APIs are the primary attack surface for modern applications, with OWASP ranking Broken Object Level Authorization as the #1 API vulnerability. A single insecure API endpoint can expose your entire customer database. As organizations adopt microservices and integrate with third-party services, the number of APIs—and the attack surface—grows exponentially. Securing APIs is no longer optional; it is fundamental to protecting customer data and maintaining compliance.

Key Points

APIs are a top attack vector for modern applications

OWASP API Security Top 10 defines key vulnerabilities

Requires authentication, authorization, and rate limiting

Input validation prevents injection attacks

All API traffic should use TLS encryption

Applicable Compliance Frameworks

SOC 2 ISO 27001 PCI DSS

Related Terms

Authentication

Authentication is the process of verifying the identity of a user, device, or system before granting access to resources.

Authorization

Authorization is the process of determining what actions or resources an authenticated user is permitted to access.

OWASP Top 10

OWASP Top 10 is a regularly updated list of the most critical web application security risks, serving as a standard for application security testing.

Frequently Asked Questions

What is BOLA in API security?

Broken Object Level Authorization (BOLA) occurs when attackers can access resources belonging to other users by manipulating object identifiers in API requests (e.g., changing user_id=123 to user_id=456).

Should internal APIs be secured?

Yes. Zero trust architecture means all APIs should be secured, whether internal or external. Internal APIs are often targets in lateral movement attacks.