WebCT Input Validation Flaw Permits Remote Cross-Site Scripting Attacks Using @import url()
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SecurityTracker Alert ID: 1009591
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CVE Reference: GENERIC-MAP-NOMATCH
(Links to External Site)
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Date: Mar 29 2004
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Impact: Disclosure of authentication information, Disclosure of user information, Execution of arbitrary code via network, Modification of user information
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Fix Available: Yes
Exploit Included: Yes
Vendor Confirmed: Yes
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Version(s): 4.1.1.5, possibly other versions
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Description: An input validation vulnerability was reported in WebCT Campus Edition. A remote authenticated user can conduct cross-site scripting attacks.
Simon Boulet reported that the software does not properly filter HTML code from user-supplied input when creating new messages.
A remote user can reportedly inject scripting code within the CSS @import url() parameter (supported by Microsoft Internet Explorer
browsers).
A remote user can submit specially crafted input that, when viewed by a target user, will cause arbitrary scripting
code to be executed by the target user's browser. The code will originate from the site running the WebCT software and will run
in the security context of that site. As a result, the code will be able to access the target user's cookies (including authentication
cookies), if any, associated with the site, access data recently submitted by the target user via web form to the site, or take
actions on the site acting as the target user.
It is also reported that the software stores the user's password in a cookie,
so a cross-site scripting attack may allow a remote user to obtain a target user's password.
A similar flaw is reported in the
file upload module.
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Impact: A remote user can access the target user's cookies (including authentication cookies) associated with the site running the WebCT
software, access data recently submitted by the target user via web form to the site, or take actions on the site acting as the
target user.
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Solution: The vendor has issued the following fixes:
WebCT CE 4.1 SP2 Hotfix 40832
http://download.webct.com/ce+/4.1/hotfixes/41sp2_hotfix_rel_notes.html
WebCT
CE 4.0 SP3 Hotfix 40833
http://download.webct.com/ce+/4.0/hotfixes/40sp3_hotfix_rel_notes.html
WebCT CE 3.8.4 Hotfix 8
http://download.webct.com/ce+/3.8/hotfixes/384
_hotfix_rel_notes.html
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Vendor URL: www.webct.com/products/viewpage?name=products_campus_edition (Links to External Site)
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Cause: Input validation error
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Underlying OS: Linux (Red Hat Enterprise), Linux (Red Hat Linux), UNIX (Solaris - SunOS), Windows (2000), Windows (2003)
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Reported By: Simon Boulet <simon.boulet@divahost.net>
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Message History:
None.
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Source Message Contents
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Date: Sun, 28 Mar 2004 19:01:19 -0500
From: Simon Boulet <simon.boulet@divahost.net>
Subject: WebCT Campus Edition 4.1 - Cross site scripting using CSS @import
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Name: WebCT Campus Edition 4.1 - Cross site scripting using CSS @import
Release date: 2004/03/29
Application: WebCT Campus Edition 4.1 (4.1.1.5), possibly others
Vendor URL: http://www.webct.com/ (WebCT Inc.)
Author: Simon Boulet <simon.boulet@divahost.net>
Legal Notice:
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This Advisory is Copyright (c) 2004 Simon Boulet
You may distribute it unmodified.
You may NOT modify it and distribute it or distribute parts of it
without the author's written permission.
Disclaimer:
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The information in this advisory is believed to be true though it may
be false. The opinions expressed in this advisory are my own and not of
any company. The usual standard disclaimer applies, especially the fact
that Simon Boulet is not liable for any damages caused by direct or
indirect use of the information or functionality provided by this
advisory. Simon Boulet bears no responsibility for content or misuse of
this advisory or any derivatives thereof.
Description:
--------------------
WebCT Campus Edition is a course management system which allows the
delivery of course material and assessments online. It is used by many
colleges and universities world-wide.
This version of WebCT allows HTML tags to be inserted when posting new
messages on a forum. Although WebCT filters dangerous tags insertion,
it is possible to bypass this security, resulting in a cross-site
scripting (XSS) vulnerability.
Problem:
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Microsoft Internet Explorer allows execution of JavaScript code inside
the CSS @import url() parameter. A user could post a specially crafted
message using the @import method to insert malicious JavaScript code in
a forum thread. The inserted code could potentially steal session
cookies from users accessing the given thread.
In most circumstances, this problem would result in the user’s session
hijacking (ex.: stealing the session id). But unfortunately, WebCT
Campus Edition stores sensitive information, such as login name and
password, directly in user’s cookies.
Furthermore, the file upload module, which allows students to upload
files directly through WebCT, seems to be vulnerable to the same issue.
Example:
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A user could post the following code through a forum thread:
<style type="text/css">
@import url(javascript:alert(document.cookie));
</style>
Solution:
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The vendor was contacted on 2004/03/18 and has quickly addressed this
issue. Updates (untested) are available for the following products:
WebCT CE 4.1 SP2 Hotfix 40832
http://download.webct.com/ce+/4.1/hotfixes/41sp2_hotfix_rel_notes.html
WebCT CE 4.0 SP3 Hotfix 40833
http://download.webct.com/ce+/4.0/hotfixes/40sp3_hotfix_rel_notes.html
WebCT CE 3.8.4 Hotfix 8
http://download.webct.com/ce+/3.8/hotfixes/384_hotfix_rel_notes.html
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