This blog post explains how a security researcher bypassed Cloudflare's Web Application Firewall (WAF) to exploit a stored Cross-Site Scripting (XSS) vulnerability. Cloudflare is a widely used WAF that protects web applications from various attacks, including XSS. However, it is not foolproof, and researchers continuously find ways to bypass its defenses.
The bypass involved crafting a special payload that the WAF failed to detect or block, allowing the malicious script to be stored on the target application and executed later by unsuspecting users. Stored XSS vulnerabilities are particularly dangerous because the malicious script persists on the website and affects many users.
The blog provides technical details on the payload that managed to slip past Cloudflare's filtering mechanisms. It highlights the importance of combining WAF protection with secure coding practices and input sanitization to prevent XSS attacks effectively.
Overall, the post serves as an educational resource for security enthusiasts and developers to understand the limitations of WAFs and improve their application security against XSS threats.
For more insights, check out the original tweet here: https://twitter.com/hexaphp/status/1964466724818108619