CGI or Common Gateway Interface is an interface type for web servers to execute apps that execute like console applications running on a server that generates web pages in dynamical way. CGI program is an executable file, therefore there are a number of security measures you need to follow while using CGI programs. Most typical approach – CGI program will reside in a special directory ( with limited rights ) in order to let the web server to understand that the file is for execution only and not to display in the user’s browser.