guestbook.pl cleanses user-inserted SSI commands by removing text between "<!--" and "-->" separators, which allows remote attackers to execute arbitrary commands when guestbook.pl is run on Apache 1.3.9 and possibly other versions, since Apache allows other closing sequences besides "-->".
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub
