You can detect Lighttpd Default Page using this tool.
Lighttpd is a secure, fast, compliant, and very flexible web-server that has been optimized for high-performance environments. It has a very low memory footprint compared to other webservers and takes care of cpu-load. Its advanced feature-set (FastCGI, CGI, Auth, Output-Compression, URL-Rewriting and many more) make lighttpd the perfect webserver-software for every server that suffers load problems.
If attackers detect the technology used, they will try to detect vulnerabilities related to this application.
Only use components that do not have known vulnerabilities, only use components that when combined to not introduce a security vulnerability, and ensure that a misconfiguration does not cause any vulnerabilities.