Labs / Prototype Pollution Hunter
- Challenge
- Released 24 Sep 2025
🧬 Can you pollute the prototype chain to break application security?
This cutting-edge Node.js API handles user configuration with sophisticated object merging, but a subtle flaw in property handling creates a dangerous attack vector. 🔬 Modern applications rely heavily on dynamic object manipulation, making prototype pollution one of the most critical vulnerabilities in JavaScript environments. Master this advanced exploitation technique and discover how a single malicious property can compromise an entire application's security model! 🎯
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🔍 Prototype Pollution Hunter
🎯 Learning Objectives
- 🔧 Prototype Pollution: Understand how JavaScript prototype chain manipulation works
- 🌐 API Security: Learn about modern web API vulnerability assessment
- 📊 Object Manipulation: Master techniques for exploiting nested object processing
- 🛡️ Input Validation: Recognize the importance of proper data sanitization
🏢 Scenario
You've discovered a configuration management API for a corporate application. The system allows users to update their preferences through a REST endpoint that processes nested JSON objects. However, the developers didn't properly validate the structure of incoming data, creating an opportunity for prototype pollution attacks that could compromise the entire application's security model.
🔍 Your Mission
Analyze the API endpoints, identify the prototype pollution vulnerability, and exploit it to gain access to administrative functionality. The application's security relies on proper object property validation, but a flaw in the merge logic allows attackers to pollute the JavaScript prototype chain and bypass access controls.