RE: Websense Blocked Sites XSS
FYI: You can use a customized block page in /custom that does not display
the URL, such as creating a "Sorry, This URL is Blocked" page with your
company's logo. Heck, you can also just edit the "master.html" block page in
the /default dir to remove the URL displayed field.
-Greg
-----Original Message-----
From: 3APA3A [mailto:3APA3A@xxxxxxxxxxxxxxxx]
Sent: Friday, December 05, 2003 7:09 AM
To: Mr. P.Taylor
Cc: aleph1@xxxxxxxxxxxxxxxxx; bugtraq@xxxxxxxxxxxxxxxxx
Subject: Re: Websense Blocked Sites XSS
Dear Mr. P.Taylor,
It runs error message in context of blocked site. Now lets try to find
out possible impacts:
1. It's possible to run javascript on the user host in context of
blocked site. But it's most likely blocked site is not in list of
trusted web sites on user's host, so it's impossible to get something
different from running same script on another webpage.
2. It possible to steal cookie, submit some forms, etc, on blocked site.
But site is blocked. So, it's impossible to steal something or submit
something to this site.
Conclusion: there is no security impact
Post Conclusion: Guys, it's perfect you can find all these XSS/CSS bugs
in John Doe's guest books, Read-Doc-from-CDRom servers, etc. But please
think about _security_ impact before submitting this to _security_
related lists.
--Wednesday, December 3, 2003, 7:35:39 PM, you wrote to
dhubbard@xxxxxxxxxxxx:
MPT> Websense Blocked Sites XSS
MPT> Risk: High
MPT> Product: Websense Enterprise v4.3.0 - v5.1 (Maybe others we only
MPT> tested this version)
MPT> Product URL: http://www.websense.com
MPT> Found By: PeterT - petert@xxxxxxxxxxxxxx
MPT> Problem:
MPT> When Websense blocks a web site, it returns a web page to the browser
MPT> stating
MPT> that the site has been blocked. This error message contains the URL
which
MPT> was
MPT> requested. Websense does not do any validation or encoding of the URL
before
MPT> returning it in the error message. This allows an attacker to supply a
URL
MPT> that
MPT> contains script <JavaScript, ActiveX, VB). This script will run in the
MPT> context
MPT> of a server in the trusted domain and combined with other IE flaws can
have
MPT> serious consequences.
MPT> We have marked this as a High risk because we believe that allowing
MPT> attackers
MPT> to run arbitrary programs on your desktop at will, is a serious
problem.
MPT> Proof of Concept:
MPT> A URL like
MPT> http://BlockedSite?<SCRIPT>alert('hello')</SCRIPT> will run script.
MPT> Resolution:
MPT> The vendor has come out with a patch. Notified on Nov 29, 2003.
MPT> Thanks to Websense for fixing this issue.
MPT> Disclaimer:
MPT> Standard disclaimer applies. The opinions expressed in this advisory
are
MPT> our own and not of any company. The information within this advisory
may
MPT> change without notice. Use of this information constitutes acceptance
for
MPT> use in an AS IS condition. There are no warranties with regard to this
MPT> information. In no event shall the author be liable for any damages
MPT> whatsoever arising out of or in connection with the use or spread of
this
MPT> information. Any use of this information is at the user's own risk.
--
~/ZARAZA
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