Re: Best practices inquiry: tracking SSH host keys

From: Christopher L. Morrow (no email)
Date: Thu Jul 06 2006 - 23:58:43 EDT

  • Next message: Christopher L. Morrow: "Re: Best practices inquiry: tracking SSH host keys"

    On Thu, 6 Jul 2006, Steven M. Bellovin wrote:

    > On Thu, 29 Jun 2006 19:43:48 +0000 (GMT), "Christopher L. Morrow"
    > <> wrote:
    >
    > >
    > > On Thu, 29 Jun 2006, David W. Hankins wrote:
    > >
    > > > So, here's my "why not just":
    > > >
    > > > Why not just use Kerberos?
    > > >
    > >
    > > apparently kerberos scares people... I'm not sure I 'get' that, but :( A
    > > corp security group once for a long time 'didnt believe in kerberos',
    > > some people 'get it' some don't :(
    > >
    > Kerberos is a single point of failure; that scares people. You *know* you
    > have to keep the Kerberos server locked down tight, highly available (very
    > tricky for some ISP scenarios!), etc.

    remote datacenters, firewall/ipf/ipfw/iptables/blah, disable local
    console, only absolutely necessary user accounts... there are other
    protections, but really, make 10 copies spread them around your 'network'.
    It's not that bad, really.

    >
    > SSH is a distributed single point of failure, just like the old thick
    > yellow Ethernet. Remember how reliable and easy to debug that was?
    >
    > More seriously, the original virtue of SSH was that it could be deployed
    > without centralized infrastructure. That's great for many purposes; it's
    > exactly what you don't want if you're an ISP managing a lot of servers and
    > network elements. You really do want a PKI, complete with CRLs. I know

    ssh+kerb works, well... so do kerberized r* services... I'm not sure I see
    how they are that different from PKI. There may be some advantages to PKI,
    but there are risks and operational concerns as well. I suppose people
    should pick what works for them...

    > that (most) SSH implementations don't do that -- complain to your vendor.
    > (Note: the CAs are also single points of failure. However, they can be
    > kept offline or nearly so, booted from a FooLive CD that logs to a
    > multi-session CD or via a write-only network port through a tight
    > firewall, etc. Yes, you have to worry about procedures, physical access,
    > and people, but you *always* have to worry about those.
    >

    right, just like kerberos... I do admit I'm a fan of kerberos, run it at
    home even. anyway :) there are obviously many ways to skin this cat.


  • Next message: Christopher L. Morrow: "Re: Best practices inquiry: tracking SSH host keys"





    Hosted Email Solutions

    Invaluement Anti-Spam DNSBLs



    Powered By FreeBSD   Powered By FreeBSD