Full Disclosure mailing list archives

Re: Phishing using IE7 local resource vulnerability


From: "Matthew Murphy" <mattmurphy () kc rr com>
Date: Thu, 15 Mar 2007 14:46:16 -0700

On 3/15/07, avivra <avivra () gmail com> wrote:
Hi Robert,

Protected Mode and UAC are different security features.
But even though, it is possible to access local resource ("res://") links
with Protected Mode and UAC features enabled. You can test it yourself here:
http://www.raffon.net/research/ms/ie/navcancl/cnn.html or watch the demo
video here: http://raffon.net/videos/ie7navcancl.wmv.
The only way to mitigate this vulnerability by an out-of-the-box security
feature is to set the security level of the "Internet Zone" to "High". This
will disable "javascript:" links, so the user will not be able to click the
"Refresh the page." link in the navcancl.htm local resource page.
But, I doubt anyone will do that when they can simply just avoid clicking
any link in the "Navigation Canceled" page.

--Aviv.

On XP SP2 (and probably Vista), you can block the exploitation of this
by disabling script execution for the res:// scheme specifically.
Note that I didn't try blocking the specific resource involved in the
attack.

If you attempt to add "res://*" or "res://ieframe.dll/navcancl.htm" to
the Restricted Sites zone, this results in an entry for
"about:internet" being added.  After doing this, the "Refresh the
page" text is no longer a clickable link.  Removing the
"about:internet" entry reverses the change.  It seems that making this
change blocks scripts in ANY resource, even without the wildcard.

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