Understanding OWASP API Security Top 10: A Complete Breakdown

Why API Security is Critical

APIs are the backbone of modern applications, enabling seamless connectivity across web services, mobile apps, and cloud platforms. However, as API adoption grows, so do security threats. APIs are now the most targeted attack vector, with cybercriminals exploiting vulnerabilities to steal data, disrupt services, and compromise entire systems.

To address these risks, the Open Web Application Security Project (OWASP) has released the OWASP API Security Top 10, highlighting the most critical security threats to APIs. This guide provides a complete breakdown of these risks and actionable strategies to mitigate them.

OWASP API Security Top 10: 2023 Edition

1. Broken Object Level Authorization (BOLA)

🔓 Threat: Attackers manipulate API requests to access or modify unauthorized resources.

💥 Example Attack: A hacker changes an API request parameter to access another user’s private data.

✅ How to Fix:

• Implement role-based access controls (RBAC) and attribute-based access controls (ABAC).
• Use secure session validation to prevent unauthorized access.
• Conduct API penetration testing to identify authorization weaknesses.

2. Broken User Authentication

🔑 Threat: Weak or misconfigured authentication mechanisms allow attackers to bypass authentication.

💥 Example Attack: An attacker exploits weak API authentication by stealing OAuth tokens.

✅ How to Fix:

• Implement multi-factor authentication (MFA) for API access.
• Use OAuth 2.0, OpenID Connect, and secure JWT validation.
• Regularly rotate API keys and enforce token expiration policies.

3. Broken Object Property Level Authorization

🚨 Threat: Unauthorized users gain access to sensitive object properties through API calls.

💥 Example Attack: An attacker modifies API payload data to access hidden fields, such as user roles or privileges.

✅ How to Fix:

• Enforce strict API schema validation to prevent unauthorized field modifications.
• Use whitelisting for API responses to control exposed fields.
• Implement access control checks at multiple layers of the application.

4. Unrestricted Resource Consumption

🌪 Threat: Attackers exploit APIs by sending excessive requests, leading to DDoS attacks or system slowdowns.

💥 Example Attack: A botnet floods an API with millions of requests, crashing the service.

✅ How to Fix:

• Implement rate limiting, API throttling, and quota management.
• Use CAPTCHAs and bot protection mechanisms.
• Deploy WAF (Web Application Firewall) and API gateways to filter malicious traffic.

5. Broken Function Level Authorization

🔓 Threat: Attackers exploit improper authorization to access restricted API functions.

💥 Example Attack: A low-privilege user gains admin-level API access by altering function parameters.

✅ How to Fix:

• Implement principle of least privilege (PoLP) and fine-grained access controls.
• Use server-side authorization checks before executing API functions.
• Conduct regular access audits to identify misconfigurations.

6. Unrestricted Access to Sensitive Business Flows

⚠️ Threat: Attackers manipulate API workflows to abuse business logic or financial transactions.

💥 Example Attack: A hacker abuses an API checkout process to apply unlimited discounts.

✅ How to Fix:

• Use business logic anomaly detection to detect API abuse.
• Implement rate limits on critical business transactions.
• Continuously monitor API usage patterns for fraudulent activity.

7. Server-Side Request Forgery (SSRF)

📡 Threat: Attackers manipulate API requests to make unauthorized requests to internal systems.

💥 Example Attack: A hacker exploits an API endpoint to access internal AWS metadata.

✅ How to Fix:

• Restrict API access to internal networks using allowlists.
• Validate user-supplied URLs before processing requests.
• Implement firewalls and network segmentation to block unauthorized requests.

8. Security Misconfiguration

⚡ Threat: APIs are deployed with default settings, unnecessary HTTP methods, or open debug endpoints.

💥 Example Attack: An API test endpoint is accidentally exposed, revealing admin credentials.

✅ How to Fix:

• Apply secure API deployment configurations.
• Disable unnecessary API methods and features.
• Conduct regular security audits and automated configuration scanning.

9. Improper Inventory Management

👻 Threat: Shadow APIs, outdated versions, or undocumented endpoints create security blind spots.

💥 Example Attack: An attacker exploits an old, forgotten API version with known vulnerabilities.

✅ How to Fix:

• Maintain a complete API inventory using API discovery tools.
• Enforce version control policies and deprecate outdated APIs.
• Use automated API scanning to identify hidden endpoints.

10. Unsafe Consumption of APIs

🔗 Threat: APIs consume untrusted third-party services without proper validation.

💥 Example Attack: A third-party API integration is compromised, leading to data exfiltration.

✅ How to Fix:

• Vet all third-party API providers for security risks.
• Implement input validation and sanitization for external APIs.
• Use sandbox environments to test external API integrations.

How Rakuten SixthSense Helps Secure APIs Against OWASP Top 10 Threats

• ✔ Advanced Threat Detection: AI-driven insights to detect and prevent API attacks.
• ✔ Zero Trust API Security: Continuous authentication and least-privilege access enforcement.
• ✔ API Discovery & Shadow API Management: Identifies unauthorized and forgotten APIs.
• ✔ Automated API Security Compliance: Ensures adherence to security frameworks and industry regulations.
• ✔ Seamless Integration with API Security Tools: Works with WAFs, SIEMs, and API gateways for complete protection.

Prioritize API Security Now

🔹 APIs are the #1 attack surface in modern applications—securing them is non-negotiable.

🔹 Understanding OWASP API Security Top 10 helps businesses proactively defend against API threats.

🔹 Combining API security best practices with observability ensures end-to-end protection.

🚀 Want to see how Rakuten SixthSense secures APIs against OWASP API threats? Request a demo today!

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