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REST API Pentesting

REST (Representational State Transfer) APIs are widely used for communication between client and server applications. Pentesting REST APIs involves identifying vulnerabilities and assessing security risks associated with these interfaces. Here's an overview of REST API pentesting, common vulnerabilities, and useful resources:


  • Communication Protocol: REST APIs use HTTP methods (GET, POST, PUT, DELETE) to perform operations on resources represented by URLs.
  • Stateless Communication: Each request from the client to the server is stateless, meaning the server does not store any client session information.

Common Vulnerabilities

Injection Attacks

  • Injection vulnerabilities (e.g., SQL injection, XPath injection) can occur if input parameters are not properly validated or sanitized. SQL injection in a parameterized SQL query used by the API to interact with the database.

Authentication and Authorization Issues

  • Weak or missing authentication mechanisms can lead to unauthorized access to sensitive resources. Lack of proper authorization checks allowing unauthenticated users to access restricted endpoints.

Sensitive Data Exposure

  • Exposing sensitive data (e.g., credentials, personally identifiable information) in API responses or logs. Including passwords or API keys in plaintext within API responses.

Insecure Direct Object References (IDOR)

  • Improperly implemented references to internal objects or resources can allow attackers to access unauthorized data. Predictable resource IDs that allow an attacker to access data belonging to other users.

Denial of Service (DoS)

  • Attackers can exploit API endpoints to exhaust server resources or cause service disruptions. Sending a large volume of requests to a resource-intensive endpoint to overload the server.

Tools & Frameworks

  • Burp Suite: Widely used for intercepting and manipulating HTTP requests and responses, helpful for analyzing REST API traffic.
  • OWASP ZAP: Open-source web application security scanner with features for testing REST APIs.
  • Postman: API development environment with capabilities for testing and debugging REST APIs.


  • OWASP API Security Top 10: OWASP's list of the most critical security risks to APIs, providing guidance on mitigating common vulnerabilities.
  • REST API Security Checklist: Checklist covering various security considerations for designing, testing, and securing REST APIs.
  • REST Security Cheat Sheet: Comprehensive guide from OWASP on securing REST APIs, covering authentication, authorization, encryption, and more.