Confused Parsers

EasyWeb Security

Overview

This challenge is designed to teach you about URL parsing confusion. The challenge will also show you the parsing results from each parser and indicate if any differences occur. Your goal is to exploit these differences to retrieve the flag. Flag Format: Flag{}

Lab Details

Prerequisites & Requirements

  • Basic web application security knowledge
  • Understanding of HTTP protocol and URL structure
  • Familiarity with SSRF vulnerabilities
  • Basic Python code reading skills

What will you learn?

  • URL parsing inconsistencies and security implications
  • SSRF bypass techniques using parser confusion
  • How different parsers can interpret the same URL differently
  • Security risks of using multiple parsers in the same application

Tools

  • Web Browser: For interacting with the web application and testing URL inputs
  • Burp Suite / OWASP ZAP (Optional): For intercepting and modifying HTTP requests
  • Text Editor / IDE: For analyzing the source code and understanding the vulnerability
  • Terminal/Command Line: For examining Docker configuration and testing
  • Python Debugger (Optional): For stepping through the parsing logic

Job Positions

Application Security Engineer

Tags

Confusion AttacksSsrfInput ValidationSource Code ReviewOwasp Top 10