Web Shell Detector – is a php script that helps you find and identify php/cgi(perl)/asp/aspx shells. Web Shell Detector has a “web shells” signature database that helps to identify “web shell” up to 99%. By using the latest javascript and css technologies, web shell detector has a light weight and friendly interface.

https://github.com/emposha/PHP-Shell-Detector

Demo: http://www.emposha.com/demo/shelldetect/

Console version (python): https://github.com/emposha/Shell-Detector