The bolded/highlighted section of data will be erroneously passed to the PHP command line interpreter and may allow the attacker to override specific PHP configurations. In this case, one of the key modifications is to specify "auto_prepend_file=php://input" which will allow the attacker to send PHP code in the request body. If we inspect the request body contents, we can see that the attacker is attempt to use various command-line web clients (wget/curl/fetch/lwp-get, etc...) to download the "mc.pl" script on the remote attacker's site. The "mc.pl" file is no longer available at that URL however Googlecache shows the contents as an IRC botnet client.