This tweet suggests several techniques for bypassing a Web Application Firewall (WAF), mainly targeting Cross-Site Scripting (XSS) vulnerabilities. The mentioned strategies include using double or triple URL encoding to evade recursive input validation checks. Another method is prefixing the payload with 'javascript:' to try to bypass filters that do not correctly parse or sanitize URI schemes. Furthermore, the tweet suggests sending a large request or using the gzip content type to bypass detection mechanisms. These techniques exploit potential oversights in how the WAF decodes or inspects encoded payloads and how it handles content-type parsing and input size limits. While not vendor-specific, these tips can be applied broadly to bypass various WAF implementations that do not robustly handle encoding, content types, or large requests.
For more insights, check out the original tweet here: https://twitter.com/EIon_AI/status/2041510138276663610. And don’t forget to follow @EIon_AI for more exciting updates in the world of cybersecurity.