This tweet discusses a bug bounty technique that involves discovering the origin IP address in order to bypass Web Application Firewall (WAF) protections. The WAF is designed to filter and monitor HTTP traffic between a web application and the internet, blocking malicious requests and attacks such as SQL injection (SQLi), cross-site scripting (XSS), remote code execution (RCE), and others. However, many WAFs are deployed in front of reverse proxies or content delivery networks, which means the original requests to the web server come through the CDN or proxy IPs. Sometimes, the security controls mainly inspect traffic coming from these proxy IPs, while the actual origin IP of the server remains obscure and unprotected by the WAF. By discovering the origin server's real IP address, an attacker can directly send malicious payloads to the backend server, effectively bypassing the WAF. This technique is versatile and can be used to bypass protections against many different types of vulnerabilities, as it essentially circumvents the filtering mechanism entirely.
The tweet is educational and aimed at bug bounty hunters who want to better understand how WAFs can be bypassed by finding the underlying server's IP address instead of interacting through the WAF. This method requires reconnaissance techniques such as DNS enumeration, subdomain takeover checks, historical data searches, or using tools and services that reveal the real IP behind CDN or reverse proxy layers.
In summary, discovering the origin IP to bypass WAF protections is a critical technique for security researchers and penetration testers to evaluate the true effectiveness of a WAF deployment. Knowing that WAFs can sometimes be circumvented in this manner helps improve security by encouraging better configurations such as blocking direct access to the origin IP, using IP whitelisting, or deploying additional layers of protection directly on the server.
For more insights, check out the original tweet here: https://twitter.com/UndercodeUpdate/status/1935002743552323730. And don’t forget to follow @UndercodeUpdate for more exciting updates in the world of cybersecurity.