YA Book 0.98 Persistent XSS

[omnipresent () email it]

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"YA Book 0.98-alpha - Persistent XSS Vulnerability"
        by Omni

1) Infos
---------
Date            : 2007-04-23
Product         : YA Book
Version         : 0.98-alpha - Prior version maybe also be affected
Vendor          : http://sourceforge.net/projects/yabook - http://www.phpee.com/
Vendor Status   : 2007-04-23 -> Not Informed!
                  2007-04-24 -> Informed!

Description     :  YaBook- Ya Book! ...or yet another guestbook. YaBook is a simple but powerful guestbook running on 
PHP
                   5. It features easy installation and customization, multi-language support, and an administration
                   interface. Various database systems are supported.

Google Dork     : Powered by YaBook 0.98-alpha - "Powered by YaBook 0.98-alpha"


Source          : omnipresent - omni
E-mail          : omnipresent[at]email[dot]it - omni[at]playhack[dot]net
Team            : Playhack.net Security

2) Security Issues
-------------------

--- [ Remote Persistent XSS ] ---
=================================

YA Book is vulnerable to an XSS. A malicous user can put in the City Field HTML or JS code
(in sigin module: http://host/path/index.php?mode=sign) as shown below:

Eg script:

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

The vulnerability exist because the city field is not properly sanitized before being used!

--- [ PoC ] ---
===============

A guest can posts a new message and after put the right captcha :D he can puts in the city field a code like:

<script>location.href="http://host.com";</script>

for a redirect with JS or.. he can injects other (eg: HTML, JS) codes..


3) Patch
--------

Edit the source code to ensure that the input is properly sanitized before being used.