Re: web browser security zones

[Gary Flynn <flynngn () JMU EDU>]

Valdis Kletnieks wrote:

> On Wed, 11 Jan 2006 11:16:34 CST, Kevin Shalla said:
>
>
> > in that zone), but not much.  Do other browsers have such detailed
> > settings by security zone?  It appears that Firefox has very little
> > granularity (just load images and popups) in the security setup.
>
>
> That's because the Firefox world-view is that *all* remote sites are untrusted.

Yet its default state for scripting and other avenues
of attack is 'enabled' for *all* those sites it doesn't
trust. If scripting is turned off for any browser, the
number of defects that are available for exploitation
have in the past been significantly less.

The link below once went to a page listing defects and the
ways that the defects could be mitigated without a
patch. Almost every one said "disable scripting". I don't
seem to be able to find that information in the new format.
Interestingly, they also don't put dates next to the
security patches anymore either so its hard to discern
a timeline of security defects at one glance. ;)

http://www.mozilla.org/projects/security/known-vulnerabilities.html

I hesitate to defend a browser that has had a security defect
at least every other month for the past several years but the
ability of IE to give or take away functionality based on site
is a good idea, even though it may presently not be used or
implemented in the best way. The core functionality is in
Mozilla too but hasn't been provided a user interface by the
Mozilla folks:
http://www.mozilla.org/projects/security/components/ConfigPolicy.html

> > At 11:54 AM 1/10/2006, David Gillett wrote:
> >
> > >  I recall that, a few years back, it was common for Microsoft
> > > to downplay IE bugs with this "must get user to visit a
> > > suspicious site" argument.
> > >  And then some hacker crew broke into a hosting company and
> > > defaced 500+ legit websites, adding code that exploited some
> > > of those vulnerabilities.

Its repeatable. :)

2003
http://www.computerworld.com/securitytopics/security/story/0,10801,84675,00.html?SKC=home84675

2004
http://www.cnn.com/2004/TECH/internet/06/25/internet.attack/index.html
http://www.eweek.com/article2/0,1895,1730877,00.asp

2005
I don't recall any specific instances but there were lots of reports
of various IE defects being exploited on hacked web servers (which
I've seen more than once) and ad banners. This probably carries over
into 2006 with the WMF exploits. It kind of follows the pattern
of compromises being more stealthy than the huge and noisy ones
of the past.


> > >  The notion that users can have any real idea, a priori, about
> > > the actual safety of any site is just false.

Amen. Or email attachments. Or links. Or downloads. Or processes
running on their computers. :(

> And David explains quite well exactly why.  If, by some chance, your campus
> webserver gets defaced, then every single desktop that lists it as "trusted"
> is immediately vulnerable to compromise if they visit the now-hacked server.

Yeah, that is a real sticky situation. I cringe when I finally
convince someone to set the IE Internet zone's security to
high and they proceed to put external sports, news, weather,
and game sites into their trusted zone. But looking at it from
a risk assessment view, it has to be better than trusting the
entire Internet. While there may be a hole you could drive
a truck through, particularly if targeted, cutting the number
of sites from hundreds of millions to a few hundred, certainly
has to be a security improvement.

Its important to keep in mind that just putting a site in the
trusted zone does not automatically make the client vulnerable
to a hack. Certainly, the opportunity for a social engineering
attack is greatly increased but if your campus web site is
hacked, that won't be too hard anyway. Generally, a defect
will still need to be exploited...one that could be exploited
in IE's Internet zone or Firefox's out of the box configuration
if all it required was scripting to be enabled.

Note also that the privileges granted to sites in the trusted
zone can also be adjusted.



--
Gary Flynn
Security Engineer
James Madison University
www.jmu.edu/computing/security