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Re: Microsoft IE cookies readable via about: URLS


From: "Clover Andrew" <aclover () 1value com>
Date: Mon, 12 Nov 2001 16:14:43 +0100

Nick FitzGerald <nick () virus-l demon co uk> wrote:

This was hinted at in Andrew Clover's message of 19 October

Yes. I noted that "IE incorrectly applies HTTP-style URL parsing to
'about:' URLs", from which I really should have investigated further to
find that in fact it doesn't recognise the difference between http: and
about: at all in the case of cookie access security. My bad - having
found what I considered enough of a hole to require patching, I didn't
go further and find its full potential.

That's interesting, given they seemed to think there was no
problem (despite the flaw being obvious to the rest of the
world) back when Andrew mentioned it...

Well, my exploit was less serious than this, but it was indicative of
brokenness, and I would have expected the IE team to at least
investigate. Instead, Microsoft seemed more interested in arguing
Mitigating Factors. It would be easiest to simply remove the
about-unknown-page-echoing-"feature", since it is of no legitimate use
whatsoever (or at least enforce HTML-escaping on it). I do not expect
the patch for Jouko's more serious exploit to do so, when it's released,
but there's always hope.

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet 
Settings\ZoneMap\ProtocolDefaults\about = 4

Indeed, I've been using this a while with no problems, recommend it.

-- 
Andrew Clover
Technical Consultant
1VALUE.com AG


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