Unlike reading a textbook, Gruyere forces you to find the bugs yourself [1].

Show you to fix each vulnerability.

A modern browser feature that tells the site which scripts are safe to run. 🍪 Client-Side State Manipulation

Cross-Site Scripting occurs when an application includes untrusted data in a web page without proper validation or escaping. Gruyere contains multiple vectors for XSS:

CSRF exploits the trust a web application has in a user's browser. blog.google The Exploit:

XSS is the top threat, consistently holding the #1 spot on the CWE Top 25 with a score of 60.38, more than double that of SQL injection. It occurs when an attacker injects malicious scripts into a trusted website. In Gruyere, you can find several flavors:

It covers most of the OWASP Top 10 web vulnerabilities.

Mastery of Web Application Exploits and Defenses: A Deep Dive into Google Gruyere

Treat everything from the client as potentially malicious.

| Level | Suitability | |-------|--------------| | | ✅ Perfect start | | Student / self-learner | ✅ Great for portfolio | | Bug bounty hunter (new) | ✅ Builds foundational mindset | | Experienced pro | ❌ Too basic |

Below is a comprehensive breakdown of the top web application exploits found within Gruyere, how they work, and the exact code-level defenses required to mitigate them. 1. Cross-Site Scripting (XSS)

An attacker can use directory traversal sequences (such as ../ ) to escape the intended upload directory. This allows them to read sensitive system configuration files or overwrite critical application code. 4. Broken Object Level Authorization (BOLA / IDOR)

If you must store data on the client, sign it with a secret key so the server can detect if it has been tampered with. 🗺️ Path Traversal