White paper on an introduction to HTTP fingerprinting. Related tool demonstrating these methodologies are available here for the following operating systems: FreeBSD. Originally presented at Blackhat Briefings 2003 in Singapore.
You can download it from the following link: https://packetstormsecurity.com/files/download/32484/httprint_paper.zip
Source: https://packetstormsecurity.com/files/32484/httprint_paper.zip.html