MIME types for csh or sh shell programs must be disabled

Description

Users must not be allowed to access the shell programs.

Rationale

Shell programs might execute shell escapes and could then perform unauthorized activities that could damage the security posture of the web server. A shell is a program that serves as the basic interface between the user and the operating system. In this regard, there are shells that are security risks in the context of a web server and shells that are unauthorized.