HOW TO REPRODUCE

1. You must run Apache in any version on a Linux system and have setup an VirtualHost entry with
an example domain "www.domain.com".

2. Configure an .htaccess file like

    ErrorDocument 404 http://www.domain.com/notfound.html

3. The notfound.html file MUST NOT exist and you MUST use an external path

4. Write a php script like

      <?php
      include("http://www.domain.com/any_file_that_does_not_exist.html");
      ?>


WHAT HAPPENS

The include() function tries to get the specified document but cannot find it. So the Apache webserver
sends an 404 error together with a HTTP redirection. The include() tries to catch this address which
leads into an infinite loop. The webserver will die shortly.

HOW TO SOLVE

The include() function should have a limit on how many levels it tries to catch since the webserver is not
able to determine if the caller runs into an infinite loop.