Hook

Prerequisites & Requirements

• Understanding HTTP requests (GET/POST), how web servers handle requests, and basic API interactions
• Familiarity with SSRF (Server-Side Request Forgery) and why it's dangerous
• How domain name resolution works, what TTL means, and the basics of DNS caching
• Ability to read and understand Python/Flask code
• Understanding of IP addresses, private vs public IP ranges, and localhost

What will you learn?

• DNS Rebinding Attacks: A sophisticated technique to bypass IP-based security controls
• Time-of-Check to Time-of-Use (TOCTOU) Vulnerabilities and the gap between validation and execution
• SSRF Bypass Techniques and how to circumvent common protections that rely on DNS resolution
• Code Auditing: Identifying security flaws in server-side code by analyzing logic flow

Tools

• Python 3.x for running the exploit script
• requests library for making HTTP requests programmatically
• rbndr.us: DNS Rebinding service (no setup required)
• cURL / Browser for manual testing and interaction
• Text Editor / IDE for analyzing the source code