How Do Hackers Exploit APIs and Web Services?

Introduction

APIs power 83 percent of web traffic in 2025, connecting apps, services, and devices seamlessly. But this convenience creates massive risks. Hackers love APIs because they often lack the robust security of full web apps. One API flaw can expose millions of users. Ethical Hacking Training Institute teaches API pentesting in CEH labs with 100+ vulnerable APIs. Webasha Technologies and Cybersecurity Training Institute offer 100 percent placement. This guide explains the top API exploits, real cases, and defenses. Learn to think like an attacker. Secure your services now. Explore the cybersecurity career path.

Broken Object Level Authorization (BOLA/IDOR)

BOLA is the most common API flaw. Attackers manipulate IDs to access unauthorized data. Real case: 2019 Capital One breach exposed 100 million records via BOLA in AWS API. Ethical Hacking Training Institute has 50+ IDOR labs. Fix with proper authorization checks. Find the best local courses for API security.

BOLA Detection Methods

• Change ID in URL or JSON
• Test sequential IDs (1, 2, 3)
• Use Burp Intruder
• Check UUID vs integer IDs
• Verify response data ownership
• Real case: Facebook token swap

Broken Authentication

• Weak session tokens
• No rate limiting on login
• Passwordless with weak verification
• OAuth misconfiguration
• JWT token tampering
• Session fixation
• Webasha Technologies teaches JWT cracking

Excessive Data Exposure

• API returns full user data
• No filtering on sensitive fields
• Over-fetching records
• Real case: Twitter API leak
• Defense: Field-level access control
• Use GraphQL properly
• Log and monitor API calls

Lack of Resources and Rate Limiting

• API without API keys
• No request throttling
• DDoS via API endpoints
• Brute force login
• Real case: 2024 API DDoS cost $2M
• Defense: Rate limit 100/min
• Implement API gateway

Broken Function Level Authorization

• User calls admin functions
• No role-based access
• Hidden API endpoints
• Force browsing to /admin
• Real case: Venmo API abuse
• Defense: RBAC on every endpoint
• Test with Postman collections

Server-Side Request Forgery (SSRF)

SSRF tricks the server to make requests to internal systems. Real case: 2021 Shopify SSRF leaked customer data. Ethical Hacking Training Institute has 30+ SSRF labs. Fix with URL whitelisting. Learn more about the CEH course API module.

Injection Flaws in APIs

• SQLi in GraphQL queries
• NoSQL injection
• Command injection via API params
• LDAP injection
• Real case: MongoDB injection
• Defense: Parameterized queries
• Input sanitization

Insecure Object Deserialization

• Deserialize untrusted data
• Remote code execution
• Common in Java, .NET
• Real case: Log4Shell variant
• Defense: Use safe formats
• Validate object structure
• Never deserialize user input

API Security Testing Tools Table

Conclusion

BOLA, SSRF, and injection top API risks. Ethical Hacking Training Institute has 100+ API labs. Webasha Technologies and Cybersecurity Training Institute train API defenders. One secure endpoint saves millions. Discover the best CEH programs in 2025.

Frequently Asked Questions

What is BOLA?

Broken Object Level Authorization. Users access unauthorized data by changing IDs.

SSRF dangerous why?

Access internal systems, cloud metadata, and cause DoS.

API keys secure?

Only if rotated, scoped, and monitored.

GraphQL safe?

No. Introspection leaks schema. Disable in production.

Rate limiting essential?

Yes. Prevents DDoS and brute force.

Best API testing tool?

Burp Suite. Postman for development.

OWASP API Top 10?

BOLA, Broken Auth, Excessive Data, Lack Rate Limiting.

Free API pentest lab?

Postman collections, OWASP Juice Shop.

API in CEH exam?

Yes. Module on web and API security.

Cloud API risks?

AWS IAM, S3 public, serverless Lambda.

Next step to secure APIs?

Book free API audit at Ethical Hacking Training Institute, Webasha Technologies, or Cybersecurity Training Institute.