ASPScriptz Guest Book 2.0 Remote XSS

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        - ASPScriptz Guest Book 2.0 Remote XSS -

-= http://colander.altervista.org/advisory/ASzGB.txt =-

       -= ASPScriptz Guest Book 2.0 =-

Omnipresent
May 18, 2006

Vunerability(s):

XSS Attack

Product:

ASPScriptz Guest Book 2.0

Vendor:

http://www.aspscriptz.com

Description of product:

Guesbook is a free open source guestbook.Simply download it and unzip it and upload it into the root directory of your
server.It is working now.Smilies support it also added in this version.Admin can disable or enable HTML support.Admin
section is also included.

Vulnerability / Exploit:

From line 109 to line 113, there are the vulnerable code:

[…]

GBOOK_UNAME = REQUEST.FORM("GBOOK_UNAME")
GBOOK_EMAIL = REQUEST.FORM("GBOOK_EMAIL")
GBOOK_CITY = REQUEST.FORM("GBOOK_CITY")
GBOOK_COU = REQUEST.FORM("GBOOK_COU")
GBOOK_WWW = REQUEST.FORM("GBOOK_WWW")

[…]

As you can see, the variables:
GBOOK_UNAME
GBOOK_CITY
GBOOK_COU

are not properly sanitized before being used, so a remote attacker can inject arbitrary HTML code.

So, the programmer for delete the bug can modify the source code with a simple replace().

PoC / Proof of Concept of SQL Injection:

Not very hard… :D Just put <script>alert("XSS")</script> in the Name, City and Country fields.

Vendor Status

[2006/06/05] Vendor Informed!

Credits:

omnipresent
[email protected]