America Online Webmail Cross Site Scripting Vulnerability

["Steven Adair" <sadair () vt edu>]

Date:             October 20, 2004
Vendor:           America Online Inc.
Product/Service:  America Online Webmail
Issue:            Cross Site Scripting Vulnerability In Webmail
URL:              http://webmail.aol.com | AOL Keyword: webmail
Advisory URL:     http://www.lovebug.org/aolwebmail_advisory.txt

Note: While I found these vulnerabilities independently, all credit goes to
iDefense as upon searching I found that this scripting error has previously
been mentioned (sometime ago at that) in a white paper written by iDefense.
This white paper is available at: http://www.cgisecurity.com/lib/XSS.pdf -
However, it appears it is possible the vendor has never been notified and
that this is not a widely published vulnerability.  Since this affects the
largest ISP in the world, it might be worth publishing on a larger scale.


Service Overview:

America Online (AOL) is the world's largest Internet Service Provider.  They
provide many special online services and features that are only available to
its dialup and high speed add-on subscribers.  AOL owns many other companies
to include Netscape, which also contains the same scripting error in its
webmail client.

Exploitation:

A user can craft a URL that when viewed will conduct a Cross Site Scripting
attack.  One impact of this attack is that it can give the attacker access
to the users cookies.  The flaw lies within msglist.adp?folder=<SCRIPTING>

An example url is as follows:
http://webmail.aol.com/msglist.adp?folder=<script>alert(document.cookie)</script>

Note: A user MUST be logged into webmail for this attack to work.  Also,
AOL's webmail is only accessible to subscribers of the AOL service.  Please
read the Netscape Webmail advisory to see the differences and who is
affected by that vulnerability.


Solutions:

The script could simply filter and replace special characters or validate
user input so scripts cannot be executed.


Vendor Response:

All previous attempts to alert this vendor to other vulnerabilties,
exploits, and holes have proven to be futile.  This error has not been
reported to the vendor for that reason.  If this vendor would like to be
notified of future bugs (which there already are) in order to work on a
solution prior to disclosure, they can contact me at: steven () lovebug org

Credits:

iDefense - and credits go to Link Linkovich for also mentioning and
describing problems with Groups@AOL
---------------------------


Questions/Comments/Other?  Drop me a line.  Go Hokies! :D


-Steven
steven () lovebug org

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