Fantastic Guestbook v2.0.1 Advisory

.:. Fantastic Guestbook v2.0.1 Advisory .:.

Date of written Advisory:

July, 11 2006

Product:

Fantastic Guestbook v2.0.1

Vendor:

http://fscripts.com/

Description:

Fantastic GuestBook version 2.0.1 is simple GuestBook; where remote user without authentication can post their own message.
No authentication is required! Every body can post message.

Exploit(s) / Vulnerability(ies):

Fantastic GuestBook version 2.0.1 is affected by a Remote XSS Vulnerability.
Some variables are not properly sanitized before being used.
Here you will find the variables not properly sanitized:

[…]
'first_name'=>$_POST['first_name'],

'last_name'=>$_POST['last_name'],
'nickname'=>$_POST['nickname'],

[…]

PoC(s):

If a malicious people go into the sign in form and put in the fields First Name, Last Name and Nick Name a code like this:

<script>alert("XSS")</script>

When you load the page http://127.0.0.1/[path]/guestbook.php or you read the messages of the guestbook you will se a pop-up that "say" 'XSS'.

Vendor Status:

July, 2006/11 - Not Informed!

Solution:

At the moment (July, 2006/11) there are no solutions from the vendor. If you want to make sure the code and your GuestBook you have to sanitize the variables:
firs_name
last_name
nick_name

Credits:

omnipresent
omnipresent[at]email[dot]it
http://it.security.netsons.org