Re: Client End Firewalls

[Ansgar -59cobalt- Wiechers <bugtraq () planetcobalt net>]

On 2004-10-18 GuidoZ wrote:
> > With Windows 98 you're doomed since you have to rely on the users
> > not making mistakes :(
>
> Yeah, I've kinda had the same problem. There are ways to apply
> policies and such (poledit), which is helpful though. I've used this
> successfully to thwart some curious users.

That may or may not help, depending on the user's skills. The problem
with policies in Win9x is that you can't enforce them. Any user who
knows the way around it will be able to bypass your measures.

> (A useful write-up can be found here: http://www.zisman.ca/poledit/)
> Although, in the long run it's still Windows 98. As my father always
> said, "You can't polish a turd."

Heh.

[...]
> > Services that don't run can't be exploited and thus don't need to be
> > protected by a PFW. Services that need to be available can't be
> > protected by a PFW.
>
> While this is true, that only applies to the services that I expressly
> defined as necessary, or shut down. Again I'll remind you that I still
> have to depend on users in certain circumstances. I've been in there
> removing Spyware on a weekly basis. Having the Firewall set to allow
> access to ONLY what I have defined and password protected adds a layer
> that, again, I prefer to keep in place.

Point already taken, though with respect to spyware I would rather set
up other measures like using other browsers and restricting IE to
localhost and some pages that expressly need IE to work (see other
sub-thread).

> I'll also comment on your second statement - you certainly CAN control
> necessary services with a PFW. You can setup advanced rules and
> filters to, for example (but not limited to), only allow access to a
> machine from or to a certain IP#. That way Tom (who found the password
> on a post-it note) can't be jumping into Jane's network share even
> though it's open to Bill (who had the post-it note).

I've seen this one coming ;)

It is true that the packet filter of a PFW allows you to control
connections on a per-IP-basis. However, you should ask yourself why
users need to share folders on their desktop-PCs anyway. IMHO a central
file server would be a much more reasonable approach (think about
backups, too).

Don't get me wrong, I'm not totally against host-based packet filtering.
In some cases (like notebooks that get connected to various networks
inside and outside your company) they are indeed very useful. I just
don't see their use for computers that will always be connected to your
internal network. I prefer a reasonable network setup over software
based solutions.

As a side-note: passwords should never be noted on post-its (or their
like) and users should be educated about this. But you already know
that, right? ;)

[...]
> > Well, you don't always have to have a Checkpoint or Cisco. A small
> > packet-filtering router (or a Linux|*BSD box) may very well suffice
> > and are a lot cheaper.
>
> This is true. I've run Smoothwall a few times as a test and it's
> worked quite well. There are still some minor kinks that I've yet to
> solve through forums, lists, and Google. Maybe I'll run them by you
> off-list. =)

Feel free to do so, but don't expect too much from me. Though I have
some experience with iptables I'm far from being a professional.

> > [1] http://www.luckie-online.de/programme/UserManager/index.shtml
> > [2] http://www.fajo.de/portal/index.php?option=content&task=view&id=6
>
> I've seen #2 before, though I haven't really given it a test run.
> Thanks for the reminder. As for #1, is there an English version?

AFAIK not. I mailed that question to the author and will keep you posted
on any reply I get.

Regards
Ansgar Wiechers
-- 
"Those who would give up liberty for a little temporary safety
deserve neither liberty nor safety, and will lose both."
--Benjamin Franklin