Web host providing for secure execution of cgi programs and method of doing the same

Abstract

A web host includes a web server that provides web pages to a client. In response to a particular web page, the client sends a request to the web server to execute a CGI program stored on the web server. A redirector within the web server redirects the CGI execution request to a CGI proxy, which determines the execution mode in which the CGI program is executed. To make this determination, the CGI proxy first checks if the requested program requires authentication, and next if it belongs to a list of “special” CGI programs meant to be executed with different “safety” modes. Each CGI program in such a list corresponds to an execution mode with particular security privileges—e.g., being able to read or write to a file the user otherwise could not read or modify. If authentication is required but fails, the CGI proxy executes the requested program in a “safety” mode, according very limited privileges to the invoked program. If authentication is required and succeeds, the CGI proxy checks the requested program name against the list of “special” programs. If the program is in this list, the proxy executes it with a mode appropriate to the program; otherwise, it executes the program under the requesting user's identification. If authentication is not required at all, the CGI proxy checks the requested program name against the list of “special” programs, and then executes the program either with the appropriate mode or under the requesting user's identification.