[<prev] [next>] [day] [month] [year] [list]
Message-ID: <A4FCADDE108AD611A4A70008C7A49E0D07E08A@IDSRV10>
From: msutton at iDefense.com (Michael Sutton)
Subject: iDEFENSE Security Advisory 09.05.2002 - Multiple Vulnerabilities
at Canada.com
iDEFENSE Security Advisory 09.05.2002
Multiple Vulnerabilities at Canada.com
DESCRIPTION
Multiple Vulnerabilities at Canada.com websites exist
that could enable an attacker to access the e-mail
account or financial portfolio of Canada.com users.
1. Cross Site Scripting at http://finance.canada.com
Canada.com's finance site, located at
http://finance.canada.com allows users to track
financial portfolios. Users enter individual stock
symbols along with the quantity of shares purchased,
date purchased and commission paid. The site will then
track the gains and losses for the portfolio.
The finance site uses session cookies to maintain
state. The cookie expires when the user either closes
the browser window or logs out of the site. A cross-
site scripting (XSS) vulnerability exists that would
allow an attacker to access the session cookies of an
authenticated user. It is important to note that
because session cookies are used, the victim would need
to be logged into his portfolio at the time of the
attack.
The following URL provides a proof of concept for the
attack. If an authenticated user were to click on the
URL, their session cookies would be displayed in an
alert window:
http://finance.canada.com/bin/quote/?Symbol=%22%3C/font>
<script>alert(document.cookie)</script>&x=35&y=9
2. Weak Session IDs at http://finance.canada.com
While the aforementioned vulnerability details how an
attacker can steal session cookies via an XSS attack,
this is not necessary if the attacker knows the
username of the victim. The finance site uses the
following session cookie to maintain state for a logged
in user:
CBUSER=[username]:canada; expires=; path=/;
domain=finance.canada.com
Simply by accessing the finance page using this cookie
with an established username in the CBUSER field, it is
possible to view and edit the financial portfolio set
up by a legitimate user. The user does not need to be
logged in at the time of the attack.
3. Cross Site Scripting at http://mail.canada.com
Like many web portals, Canada.com offers free e-mail
accounts. Canada.com users can read and send e-mail
messages via a web browser by accessing the
http://mail.canada.com web site.
A cross-site scripting (XSS) vulnerability exists that
would allow an attacker to access the session cookies
of an authenticated user. It is important to note that
because session cookies are used, the victim would need
to be logged into his e-mail account at the time of the
attack.
The following web page provides a proof of concept for
the attack. If an authenticated user were to view the
web page, their session cookies would be displayed in
an alert window:
<html>
<head>
</head>
<body ONLOAD="document.forms(0).submit()">
<form method=post
action="http://mail.canada.com/mail/mailbox">
<input type=hidden name="create_name"
value="<script>alert(document.cookie)</script>">
<input type=hidden name="submitted" value="true">
</form>
</body>
</html>
ANALYSIS
The XSS exploits provide a proof of concept, but could
easily be modified to redirect the captured session IDs
to a web server controlled by the attacker. Once the
attacker obtained the session IDs they could then
hijack the victim's session and access either their
financial portfolio or email account. Both attacks
require an element of social engineering, as the victim
would need to click on the URL or view the web page.
This could be accomplished by sending the URL or web
page to the user via e-mail. The weak session IDs used
by the finance site make it trivial for an attacker to
access financial portfolios established by legitimate
users.
The financial portfolios are not linked to brokerages
and an attacker would not therefore be able to cause
financial harm to the victim. However, this does
present a privacy risk due to the fact that many people
use this site to track established portfolios. An
attacker could therefore use this attack to gain
detailed financial information.
By using the XSS attack for the mail site, an attacker
could access the e-mail account of a legitimate user.
Once the account is accessed the attacker could view
the victim's e-mail messages or send messages from
their account. This attack presents privacy and non-
repudiation risks.
DETECTION
All users that have established financial portfolios or
e-mail accounts at Canada.com are vulnerable.
VENDOR RESPONSE
Numerous attempts were made to contact the web site
administrator(s) to inform them of the vulnerabilities
but no response has yet been received.
DISCLOSURE TIMELINE
August 21, 2002 - Initial administrator contact
attempted
August 26, 2002 - Second attempt at administrator
contact
August 26, 2002 - Disclosed to iDEFENSE clients
September 5, 2002 - Public cisclosure
Michael Sutton, CISA
Senior Security Engineer
iDEFENSE Labs
14151 Newbrook Drive, Suite 100
Chantilly, VA 20151
voice: 703-344-2628
fax: 703-961-1071
msutton@...fense.com
www.idefense.com
Powered by blists - more mailing lists