php怎么繞過登陸驗證？

下面是登陸規(guī)則：

if($action=="login"){

$adminuser = var_request("username","");

$adminpass = md5(var_request("password",""));

if($adminuser==$manage_adminname && $adminpass == $manage_adminpass ){

SetCookie("COOKIEadminuser", $adminuser);

$_SESSION['adminuser'] = $adminuser;