We don't want to use Microsoft's, whatever we do, because it promotes their
own borked browser IE9.

On Fri, Jun 3, 2011 at 11:30 AM, Mark Dilley <[email protected]> wrote:

> <aside from main conversation>
>
> Would it be a good community gesture to join Microsoft in trying to
> eradicate IE6?
>
> http://TheIE6Countdown.com
>
> or to not join them and put up a more general banner
>
> http://IE6NoMore.com
>
> and move on?
>
> </aside from main conversation>
>
>
> On 03Jun2011, at 10:53 AM, Brion Vibber wrote:
>
> > On Thu, Jun 2, 2011 at 5:21 PM, Tim Starling <[email protected]
> >wrote:
> >
> >> On 03/06/11 06:56, Brion Vibber wrote:
> >>> For 1) I'm honestly a bit willing to sacrifice a few IE 6 users at this
> >>> point; the vendor's dropped support, shipped three major versions, and
> is
> >>> actively campaigning to get the remaining users to upgrade. :) But I
> get
> >>> protecting, so if we can find a workaround that's ok.
> >>
> >> We can't really do this without sending "Vary: User-Agent", which
> >> would completely destroy our cache hit ratio. For people who use Squid
> >> with our X-Vary-Options patch, it would be possible to use a very long
> >> X-Vary-Options header to single out IE 6 requests, but not everyone
> >> has that patch.
> >>
> >
> > I'm really thinking more along the lines of: if someone's an IE
> 6-or-below
> > user they have hundreds of other exploit vectors staring them in the face
> > too, and we can't protect them against many of them -- or ANY of them if
> > they're visiting other sites than just an up-to-date MediaWiki.
> >
> > The cost of this fix has been immense; several versions of the fix with
> > varying levels of disruption on production sites, both for IE 6 users and
> > non-IE 6 users, and several weeks of delay on the 1.17.0 release.
> >
> > I'd be willing to accept a few drive-by downloads for IE 6 users; it's
> not
> > ideal but it's something that their antivirus tools etc will already be
> > watching out for, that end-users already get trained to beware of, and
> that
> > will probably *still* be exploitable on other web sites that they visit
> > anyway.
> >
> >
> > The main issue here is that we don't a wide variety of web servers set
> >> up for testing. We know that Apache lets you detect %2E versus dot via
> >> $_SERVER['REQUEST_URI'], but we don't know if any other web servers do
> >> that.
> >>
> >> Note that checking for %2E alone is not sufficient, a lot of
> >> installations (including Wikimedia) have an alias /wiki ->
> >> /w/index.php which can be used to exploit action=raw.
> >>
> >
> > Well that should be fine; as long as we can see the "/wiki?/foo.bat" then
> we
> > can identify that it doesn't contain an unencoded dot in the path.
> >
> > It sounds like simply checking REQUEST_URI when available would eliminate
> a
> > huge portion of our false positives that affect real-world situations.
> > Apache is still the default web server in most situations for most folks,
> > and of course runs our own production servers.
> >
> >
> >>
> >>> Are there any additional exploit vectors for API output other than HTML
> >> tags
> >>> mixed unescaped into JSON?
> >>
> >> Yes, all other content types, as I said above.
> >>
> >
> > Only as drive-by downloads, or as things that execute without
> interaction?
> >
> >
> >> I think the current solution in trunk, plus the redirect idea that
> >> I've been discussing with Roan, is our best bet for now, unless
> >> someone wants to investigate $_SERVER['REQUEST_URI'].
> >>
> >
> > *nod* Checking REQUEST_URI is probably the first thing we should do when
> > it's available.
> >
> >
> >> If there is an actual problem with ForeignAPIRepo then we can look at
> >> server-side special cases for it. But r89248 should allow all API
> >> requests that have a dotless value in their last GET parameter, and a
> >> quick review of ForeignAPIRepo in 1.16 and trunk indicates that it
> >> always sends such requests.
> >>
> >
> > Yay! That's one less thing to worry about. :D
> >
> >
> >> Since we're talking about discarded solutions for this, maybe it's
> >> worth noting that I also investigated using a Content-Disposition
> >> header. The vulnerability involves an incorrect cache filename, and
> >> it's possible to override the cache filename using a
> >> Content-Disposition "filename" parameter. The reason I gave up on it
> >> is because we already use Content-Disposition for wfStreamFile():
> >>
> >>       header( "Content-Disposition:
> >> inline;filename*=utf-8'$wgLanguageCode'" . urlencode( basename( $fname
> >> ) ) );
> >>
> >> IE 6 doesn't understand the charset specification, so it ignores the
> >> header and goes back to detecting the extension.
> >>
> >
> > Good to know.
> >
> > -- brion
> > _______________________________________________
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> > [email protected]
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>
>
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