Apache mod_cgi Bash Environment Variable Injection (Shellshock) Scanner

This module scans for the Shellshock vulnerability, a flaw in how the Bash shell
handles external environment variables. This module targets CGI scripts in the
Apache web server by setting the HTTP_USER_AGENT environment variable to a
malicious function definition.

PROTIP: Use exploit/multi/handler with a PAYLOAD appropriate to your
CMD, set ExitOnSession false, run -j, and then run this module to create
sessions on vulnerable hosts.

Note that this is not the recommended method for obtaining shells.
If you require sessions, please use the apache_mod_cgi_bash_env_exec
exploit module instead.