comments inline below
Many IDS vendors are integrating Firewalls into their product, just like
Firewall vendors are trying to catch up on the Layer 7 analysis. Both
types of technologies are coming tgether to some degree. We've actually
embedded pf (freebsd's firewall) into our product now. The difference
really will be WHERE you want to deploy and what your requirements are.
For example, most companies with IPS products (such as ISS, NFR, etc),
are generally implemented in a "bridging" mode. i.e. even though they
are doing firewalling, they are still invisible to the network and don't
require changes to the network architecture to implement them. Bridging
firewalls are probably not what you want on the perimeter, and so you
should look to a more traditional firewall. Traditional firewalls are
not invisible, meaning they can do more traditional firewall roles
including NAT, routing, and other fun stuff. The downside there is that
they are also exposed to attack.
Just cause your in L2 mode doesn't make you immune to attack
(http://www.cve.mitre.org/cgi-bin/cvekey.cgi?keyword=tcpdump). The box still
has to process packets just like any other L3 app. I'm not sure how bridge
mode makes a box "invisible". Besides, the device still needs an IP on the
local network for management. Sounds like security through obscurity to me.
Invisible in the sense that the interfaces that pass traffic do not have
IP addresses. And yes, the device must have an IP address on the
management side, but that's generally deeper in the network. I'm not
sure that's obscurity... that's simply smart management. Many customers
have completely out of band management networks. And yes, it's possible
to compromise systems that are simply sniffing... but it's much harder.
I know of only one product that's been successfully remotely exploited
in this manner, and the only reason that happened was because it was an
opensource product that allows hackers to read the source code and look
for ways to compromise it.
With the obvious success of IPS technologies at the perimeter, I find it
hard to believe that IPS and FW technologies will remain disparate
technologies for more than a few more years. The IPS vendors need to do one
of two things:
1. Find a good firewall vendor to acquire them or
2. Build a full featured firewall from scratch.
IPS technologies are actually just as (if not more) successful
internally than on the perimeter. I would argue that they are not
disparate technologies even today. NFR's appliances are essentially
FreeBSD based, and so we've integrated FreeBSD's pf into the product
which is a fully functional firewall. It's providing the pretty GUI
overlay that CheckPoint and other traditional firewall vendors have had
for years that is the hard part. Fortunately, we (the collective IPS
vendor market as a whole) get to learn from their mistakes and successes.
What I'm getting at is that Defense in Depth still applies, even though
these two technologies seem to be coming together rather quickly. If
you deploy a true routing firewall on your perimeter, you should protect
it with an invisible IPS product (there have been plenty of cases of
routing firewalls being compromised). Internally, when you create your
quarantine areas, most organizations don't require advanced firewalling
features such as NAT and routing. In those cases, it might be a good
fit for a bridging firewall (like today's IPS vendors).
Does anybody care about best of breed anymore?
This is probably not going to be well received on this particular list but I
think it holds true... Talking to Chris Hovis the other day, he mentioned
that what (most) customers want is "good enough security". This means that
as long as the technology works and the problem gets solved, the technology
is "good enough". Are all those neato-gizmos that the best-of-breed vendors
provide valuable? Sure, but at the end of the day customers want to pay
"just enough" to solve the problem.
PS: and once again, ISS is in the gane for 10 long years. What about
the competitors?
NFR was founded in 1996 and still chugging away. ;)
Thanks,
Stephane
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--
David W. Goodrum
Senior Systems Engineer
NFR Security
703.731.3765
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to learn more.
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