My implementation

EasySecure Coding

Overview

Visit /challenge/ to access a machine containing the source code of an application located in the preview directory. Your task is to fix the code to retrieve the flag. Make sure to read the rules before you begin.

Flag Format: Flag{}

Lab Details

Prerequisites & Requirements

  • Basic understanding of PHP
  • Familiarity with JWT (JSON Web Tokens)
  • Knowledge of HMAC and hashing algorithms
  • Ability to read and analyze source code
  • Basic debugging and testing skills

What will you learn?

  • How JWT signature verification works
  • Common mistakes in implementing custom JWT handling
  • How improper error handling can lead to security bypass
  • How to validate algorithms securely in PHP
  • Importance of using secure comparison functions like hash_equals

Tools

  • IDE
  • Browser

Job Positions

Penetration Tester

Tags

Error HandlingDynamic AnalysisCode ReviewException HandlingSecure SessionsSecure Cookies