A very secure option is to put the PHP parser binary somewhere
     outside of the web tree of files.  In /usr/local/bin, for example.  The only real
     downside to this option is that you will now have to put a line
     similar to:
     
     as the first line of any file containing PHP tags.  You will also
     need to make the file executable.  That is, treat it exactly as
     you would treat any other CGI script written in Perl or sh or any
     other common scripting language which uses the
     
#! shell-escape mechanism for launching
     itself.
    
     To get PHP to handle PATH_INFO and
     PATH_TRANSLATED information correctly with this
     setup, the PHP parser should be compiled with the --enable-discard-path
     configure option.