Raptor WAF – C Based Web Application Firewall

Raptor WAF is a Web Application Firewall made in C, using DFA to block SQL Injection, Cross Site Scripting (XSS) and Path Traversal.

DFA stands for Deterministic Finite Automaton also known as a Deterministic Finite State Machine.

It’s essentially a simple web application firewall made in C, using the KISS principle, making polls using the select() function, it’s not better than epoll() or kqueue() from *BSD but it is portable.


WAF stands for Web Application Firewall. It is widely used nowadays to detect and defend against most commonly SQL Injections and XSS attacks.

  • Block XSS, SQL Injection attacks and path traversal
  • Blacklist IPs to block users using config/blacklist ip.txt
  • Supports IPv6 and IPv4 for communication

Coming in the Future

  • DoS protection
  • Request limits
  • Rule interpreter
  • Malware detection for uploads
  • SSL/TLS Support

Do bear in mind this is an early stage almost PoC tool and not really production tested or ready, I think it’d be a great project to contribute to and most people don’t need a super complex WAF – just something REALLY reliable, stable, performant and blocks 80-90% of the common attacks.

Other options for a WAF:

NAXSI – Open-Source WAF For Nginx
Amazon AWS Web Application Firewall (WAF ) Launched
ModSecurity – Open Source Web Application Firewall

You can download Raptor WAF here:


Or read more here.

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