API Security: Best Practices for Protecting Your Digital Gateways

In today’s digital era, API (Application Programming Interface) is the fundamental part of modern software systems, mobile apps, and cloud services, API is the bridge between different components, systems, and services. But accountability breeds response-ability.—and API security is more important than ever.

What is an API? Gain a comprehensive understanding of the API ecosystem, including its components, standards, and best practices, in our detailed guide

According to Gartner, by 2025, more than 90% of web applications will be easier to attack through their APIs than through their user interfaces.

Some Real-World Examples:

• T-Mobile (2021): API exposed customer data including IMEI numbers and phone numbers due to poor access control.

Read Complete Customer Information

• Parler (2021): Public API exposed user data due to lack of authentication and input validation.

Read News posted in USA Today

What Is API Security?

API security involves protecting APIs from unauthorised access, misuse, and attacks that prevents data breaches, service interruptions, and other vulnerabilities arising from poorly designed, unsecured, or publicly exposed APIs.

APIs are like doors to your digital house. If you don’t lock them, anyone could walk right in.

API Security

Common API Security Risks

Common vulnerabilities observed in most of the APIs are:

• Broken Object Level Authorization and Authentication

  Attackers can access other users’ data by manipulating object IDs. Weak or misconfiguration of authentication leads to unauthorized access.

• Excessive Data Exposure

  APIs return more data than necessary—sometimes sensitive.

• Lack of Rate Limiting

  Allows denial-of-service (DoS) / Distributed denial-of-service (DDoS) attack or brute-force attacks by sending multiple requests simultaneously (flooding with fake requests).

  
  

• Injection Attacks

  Attacker can send SQL or NoSQL injection by adding malicious query in request parameter using non validated input.

• Security Misconfiguration

  Misconfigured headers, verbose error messages, or exposed metadata may lead to expose of sensitive data to the attacker.

Every developer or security professional must-know about the OWASP's API Security Top 10 list.

You can also join API Security Mailing List.

API Risks & Security

Best Practices for Securing APIs

Let’s walk through some essential best practices to secure your APIs:

• Use Strong Authentication & Authorization

  Implement OAuth or JWT (JSON Web Tokens) for secure identity handling. Use Role-Based Access Control (RBAC) or Attribute-Based Access Control (ABAC).

• Validate All Inputs

  Always validate and sanitize data / parameters of API request.

• Implement Rate Limiting and Throttling

  To Prevent brute-force or denial-of-service attacks, use tools like API gateways using custom service or third party application like nginx.

• Enforce HTTPS (TLS)

  Ensure all communication with your API uses HTTPS to prevent man-in-the-middle attacks.

• Secure API Keys and Tokens

  Encrypt API keys and always validate the tokens passed in request.

• Enable Logging and Monitoring

  Track all API activity. Set up alerts for abnormal patterns (e.g., spike in 401 errors).

• Limit Data Exposure

  Return on requested data. avoid sending unnecessary fields / data in API responses.

• Use CORS Carefully

  Configure Cross-Origin Resource Sharing (CORS) to restrict domains that can access your API.

Tools and Technologies for API Security

• API gateways: Azure API Management, AWS API Gateway, Kong, Apigee

• Security scanners: OWASP ZAP, Postman Security Testing, Burp Suite

• Monitoring/logging: Splunk, Datadog, ELK Stack

• Static analysis tools: Snyk, Checkmarx

Checklist for Developers

Here's a quick checklist to follow during development:

• Is every endpoint authenticated?

• Is user access properly restricted (authorisation)?

• Are all request inputs validated?

• Is HTTPS enforced?

• Are API keys and secrets stored securely?

• Is rate limiting in place?

• Are logs monitored for unusual activity?

• Are tokens short-lived and refreshable?

This is all about API Security. Every Developer / Security Tester must know about security models. You can build very secure and robust API by following Developers Checklist.

Stay tuned for our next post!