This whitepaper document how the brute forcing exploit works for a buffer overflow vulnerability in nginx versions 1.3.9 and 1.4.0 on x86.
You can download it from the following link: https://packetstormsecurity.com/files/download/122517/nginx_exploit_documentation.pdf
Source: https://packetstormsecurity.com/files/122517/Nginx-1.3.9-1.4.0-Exploit-Documentation.html