nanog mailing list archives

Re: NAT firewall for IPv6?


From: Chase Christian <madsushi () gmail com>
Date: Tue, 5 Jul 2016 15:24:44 -0700

The original email was not a serious question, but a joke:

https://twitter.com/SwiftOnSecurity/status/749059605360062464
https://twitter.com/SwiftOnSecurity/status/749062835687174144
https://twitter.com/SwiftOnSecurity/status/749068172460847105



On Tue, Jul 5, 2016 at 1:41 PM, Naslund, Steve <SNaslund () medline com> wrote:

It is all about defense in depth.  The engineers here are speaking to the
network pieces (the second N in NANOG is network, right :) and we have told
this person that it is unlikely that v6 in the only vector and I myself
talked about malware handling on the clients themselves.  From a network
engineering perspective many of us agreed that the biggest single threat to
his network was a firewall in an unknown state with an unknown
administrator password that could be owned by anyone on earth at this
point.  That single piece threatens the entire network as a whole and is a
ticking time bomb ready to blow his entire LAN off the Internet if it fails.

He probably does not own the entire environment himself, he is filling in
for a vacationing network engineer.  So he is working on the network piece
and is probably not responsible for the anti-malware software on the
clients (if anyone is, see below).

Our "support" as you call it was a response to this person questions about
blocking v6 as an attack vector in the first place.  We answered his
question but then told him that was unlikely to be the problem and what he
should do about taking back his firewall, securing v6 via the firewall, and
handling the malware at the client.  Seems solid advise to me so far.

BTW we did not bill him for anything.  He got a lot of free advice from a
lot of people he could not even begin to afford to employ, so not a bad
deal for him.  You also have to understand that this gentleman seems to be
in an educational environment which usually means lots of clients he does
not have control over so having some kind of network based malware control
is helpful.  Clients in this type of environment have to defend themselves
from each other and he will likely have stuff brought in from the outside.
Good malware detection in the network can help identify clients that
contain malware and are a threat to other devices.  Fancier network
gear/IDS/IDP would actually remove offending clients from the network or at
least segments them into an isolation area.

Let me re-iterate:

        1.      Take back ownership of your firewall and bring it up to
date including new malware signatures.  If you don't have current support,
get it...........directly so if your consultant bails you are not dead
meat.  This will ensure that the outside world will not own or control
stuff inside your network while you put the fires out.  At the very least
it can help malware infected machines from phoning home to their command
and control servers which sometimes prevents a lot of damage.
        2.      Make your v6 rules mirror at least the security level of
your v4 rules.  Passing v6 unchallenged is unacceptable.  If your firewall
won't do it replace it with one that will.
        3.      Ensure all clients under your control have current
anti-virus/anti-malware detection.  Clients have to defend themselves from
threats internal to the firewall as well as ones outside.  Don't be hard on
the outside with a soft chewy center.
        4.      Never, ever accept anything less than full administrative
control passwords and accounts from your consultants, before you give them
final payment.  I actually prefer to lock them out when they complete an
install until I need them to help with something.  This prevents them from
holding you hostage or one of their "postal" employees from wiping you out
as well as preventing them from using your network for experimentation
without you knowing it.  It is an important part of change control to
ensure that outsiders cannot modify your configuration without contacting
you first.  We usually give our consultants highly logged VPN accounts that
we can disable or enable as needed.

Steven Naslund
Chicago IL



No while that is also needed, it is very unlikely to fix his issue. The
issue at hand is that some of their computers have become virus infected.
The fix for that is to upgrade the virus scanner and making sure that
all software upgrades are done.

Someone comes to you and says his Firefox is getting infected through
IPv6.
If your support is worth anything, you will not take that at face value
and bill him for a ton work related to IPv6. No, you will go find out what
the real issue is and solve that. The only thing we know right now is that
he is >>confused.

Regards,

Baldur



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