Invicti identified Webalizer which is a free web server log analysis software. This information can help an attacker to gain a greater understanding of the systems in use and potentially to develop further attacks.
An attacker can search for specific security vulnerabilities for the version of Webalizer identified. More importantly Webalizer discloses too much information about hidden pages (config, administration etc.).
Configure your web server to prevent information leakage from the
Webalizerdirectory by implementing access control mechanisms to stop public access.