Course

This exercise delves into the exploitation of Cross-Site Leak (XS-Leak) vulnerabilities, a prevalent issue in contemporary web applications. The main challenge is to leak information by comparing response times of requests in a victim's browser. The lab provides a practical example, similar to an issue found in Google's bug tracker, where timing differences reveal sensitive data. The exploitation process involves creating an HTML page that makes use of `performance.now()` to measure the time taken for requests, helping to determine if a character is part of a sensitive key. By iteratively testing characters from a predefined set, the attacker can gradually reconstruct the key.

The course emphasizes the importance of understanding XS-Leak vulnerabilities due to their potential impact on modern applications. Participants are guided through the process of writing a payload, creating a user, and executing the attack. The lab concludes with a reflection on the significance of this type of vulnerability and encourages learners to apply these techniques in ethical hacking scenarios. The video transcript complements the written content by providing a step-by-step walkthrough of the exploit, highlighting the nuances of timing attacks and the importance of resuming the attack if necessary.