Re: Distributed Firewall

From: Joerg Over (over@dexia.de)
Date: 04/23/03

  • Next message: Robinson, Sonja: "RE: RE : PGP versus PKWare" 
    Date: Wed, 23 Apr 2003 20:00:55 +0200
To: <security-basics@lists.securityfocus.com>
From: Joerg Over <over@dexia.de>

    Am 15:12 23.04.2003 +0100 teilte Kendric mir folgendes mit:
    ->Hi, just wondering if any of you guys heard of this concept of
    distributed
    ->firewall? I have done some research on it and found it to be
    quite a
    ->wonderful concept into bringing the firewall platform to each
    client/server
    ->end with a central management policy. In other words, it is
    like having a
    ->personal firewall on each individual machine, but centrally
    managed by a
    ->remote management console. In this way, we will not have to put
    any trust
    ->even on the machines on the intranet. Any comments?

    I just evaluated NICs with embedded firewall for our company,
    with which a hardware based distributed fw can be made/managed.
    It so very much depending on the environment you're deploying
    them that it's hard to generally tell what use those are, but
    some things should be considered:

    As for sniffing prevention/egress filtering:
    IMHO on that topic they're almost useless. You can always get
    around them by just plugging in another NIC (if you have admin
    rights on the station) or just plug the cable into a laptop you
    bring in, and egress filtering and sniffing prevention are gone.
    Similar is valid for software pfws. To enforce egress filtering
    even in that setting, you could use routers and switches with a
    tight policy on mac adresses and/or vlans, but then again that
    can be circumvented (setting the ip/mac on the adapter, other
    ways of circumventing vlans, arp spoofing et al), and if it
    couldn't, that strict environment alone would be sufficient; no
    need for the nics then.

    As for ingress filtering:
    In this situation a distributed fw can be very powerful. Insofar
    as ingress filtering mainly protects the filtered station it's
    valuable, but not what you intended.

    In summary I'd believe that if you don't trust your intranet,
    don't trust it. Meaning: protect your servers (or, generally,
    valuable systems under your control) and watch for intrusions. I
    wouldn't know a way to force that trust into an intranet in a way
    that the (imo rather minor) improvement on the security end isn't
    outweighed by the administrative overhead.

    This, of course, IMHO and YMMV, and one can easily imagine a
    surrounding where every bit of improved security counts enough to
    warrant the work, or where more physical security enforces the
    use of the firewall on the station end.

    hth, jo

    ---------------------------------------------------------------------------
    Attend Black Hat Briefings & Training Europe, May 12-15 in Amsterdam, the
    world's premier event for IT and network security experts. The two-day
    Training features 6 hand-on courses on May 12-13 taught by professionals.
    The two-day Briefings on May 14-15 features 24 top speakers with no vendor
    sales pitches. Deadline for the best rates is April 25. Register today to
    ensure your place. http://www.securityfocus.com/BlackHat-security-basics
    ----------------------------------------------------------------------------

  • Next message: Robinson, Sonja: "RE: RE : PGP versus PKWare"

    Relevant Pages

    • Re: A firewall wont stop this one
      ... instead of port filtering with a piece of crap. ... If "some sort of protection" cannot be calculated, ... Firewall" a black-box filtering solution is meant, ... OpenSSH had security flaws, that's right. ...
      (alt.computer.security)
    • Re: win xp firewall
      ... Trust me a friend of mine and I tested it. ... Closing popup after popup would, IMO, qualify since ... I also never referred to it in particular as a 'security ... > The firewall is not ment to block services that are already on. ...
      (comp.security.firewalls)
    • Re: Security and the User experience
      ... Why should we trust Verisign, ... Microsoft should be placed square in the resource funding for starting this ... Trimming the firewall down or pumping it up is still ... having to deal with security. ...
      (microsoft.public.security)
    • Re: [fw-wiz] State of security technology for the enterprise
      ... Build in security zones, dmz, transit, low to high zones. ... Content filtering on the firewall ...
      (Firewall-Wizards)
    • Re: Is additional firewall necessary?
      ... deactivate any desktop firewall, but by not using such a firewall ... NOT use a feature or to NOT trust some random stranger. ... When it comes to deciding the level of security to be taken, ...
      (comp.security.misc)