From: Ben Butler (no email)
Date: Sat Feb 02 2008 - 17:42:22 EST
"If you're trying to do it on a /32 basis, I doubt you'd find too many
border router operators interested in accepting a route that small, but
I may be wrong."
Well then they wouldn't be peering with this route reflector in the
first place.
-----Original Message-----
From: Tomas L. Byrnes [mailto:]
Sent: 02 February 2008 20:39
To: Ben Butler; Paul Vixie;
Subject: RE: Blackholes and IXs and Completing the Attack.
You could achieve the exact same result simply by not advertising the
network to your peers, or by advertising a bogus route (prefixing a
known bogon AS for the addresses you want null-routed). I realize you
would have to subnet/deaggregate your netblocks, and therefore could
wind up with a prefix-length issue for peers who won't accept routes
longer than a certain mask, in some cases, but if you are already being
DDOSed, this should represent SOME improvement.
If you're trying to do it on a /32 basis, I doubt you'd find too many
border router operators interested in accepting a route that small, but
I may be wrong.
The bigger issue with all these approaches is that they run afoul of a
patent applied for by AT&T:
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u
=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=200
60031575&OS=20060031575&RS=20060031575
USPTO App Number 20060031575
> -----Original Message-----
> From: [mailto:] On Behalf
> Of Ben Butler
> Sent: Saturday, February 02, 2008 12:17 PM
> To: Paul Vixie;
> Subject: RE: Blackholes and IXs and Completing the Attack.
>
>
> Hi,
>
> I was not proposing he Null routing of the attack source in the other
> ISPs network but the destination in my network being Null routed as a
> destination from your network out.
>
> This has no danger to the other network as it is my network that is
> going to be my IP space that is blackholed in your network, and the
> space blackholed is going to be an address that is being knocked of
> the air anyway under DoS and we are trying to minimise collateral
> damage. I cant see where the risk to the large NSP is - given that
> the route reflector will only reflect /32s that legitimately originate
> (as a destination not a source) in the AS announcing them as please
> blackhole.
>
> For complete clarity: AS13005 announces 213.170.128.0/19 and has its
> route object in RIPE as being announced by AS13005.
> My router at IX - BENIX say - announces 213.170.128.1/32 to the router
> reflector their, the announcement from my IX assigned address
> 212.121.34.30 is known to be my router on the exchange, and I am
> announcing a /32 from my AS for a route object registered as being
> announced by my AS - so the reflector accepts my announcement and
> reflects it to any other members that choose to peer with this
> reflector - effectively this is a please blackhole this destination in
> AS13005 - the other members that receive this announcement can then
> deal with it in anyway they see fit from ignoring it to setting
> next-hop 192.0.2.1 -> Null0.
>
> The effect of this would be that any BotNet controlled hosts in the
> other member network would now be able to drop any attack traffic in
> their network on destination at their customer aggregation routers.
>
> I think you might have thought I was suggesting we blackhole sources
> in other peoples networks - this is definatly not what I was saying.
>
> So, given we all now understand each other - why is no one doing the
> above?
>
> At the end of the day if an IX member doesn't want the announcements
> don't peer with the blackhole reflector, simple, and it will get Null
> routed as soon as it hits my edge router at the IX - it would just
> seem more sensible to enable people to block the traffic before it
> traverses the IX and further back in their own networks.
>
> So?????
>
> Ben
>
>
>
> -----Original Message-----
> From: [mailto:] On Behalf
> Of Paul Vixie
> Sent: 02 February 2008 17:32
> To:
> Subject: Re: Blackholes and IXs and Completing the Attack.
>
>
> ("Ben Butler") writes:
>
> > ...
> > This hopefully will ensure a relatively protected router
> that is only
> > accessible from the edge routers we want and also secured to only
> > accept filtered announcements for black holing and in consequence
> > enable the system to be trusted similar to Team Cymaru.
> > ...
>
> This sounds like another attempt to separate the Internet's control
> plane from its data plane, and most such attempts do succeed and are
> helpful (like NSP OOB, or like enterprise-level anycast of DNS).
> However, I'm not sure that remote triggered blackholes are a good
> direction, worthy of the protection you're proposing, for three
> reasons.
>
> First, because large NSP's simply cannot afford the risk associated
> with letting a third party, automatically and without controls or
> audits, decide in real time what sources or destinations shall become
> unreachable. With all respect (which is a lot) for spamhaus and cymru
> and even MAPS (which I had a hand in, back in the day), feeding BGP
> null-routes to a multinational backbone is a privilege that ISO9000
> and SarBox and liability insurance providers don't usually want to
> extend.
>
> Second, because many backbone routers in use today can't do policy
> routing routing (which is in this case dropping packets because their
> source address, not their destination address, has a particular
> community associated with it) at line speed. Note, this is
> many-not-all
> -- I'm perfectly aware that lots of backbone routers can do this but
> not everybody has them or can afford them and those who have them tend
> to be the multinational NSPs discussed earlier.
> To prevent our DDoS protection reflexes from lowering an attacker's
> cost (by automatically blackholing victims to protect the nonvictims),
> we have to be able to blackhole the abusive traffic by source, not by
> destination.
>
> Third, because many OPNs (other people's networks) still don't filter
> on source address on their customer-facing edge, and thus allow
> spoofed-source traffic to exit toward "the core" or toward a victim's
> NSP who cannot filter by source due to path ambiguities inherent in
> "the core", any wide scale implementation of this, even if we could
> get trusted automation of it at scale and even if everybody had
> policy-routing-at-like-speed, would just push the attackers toward
> spoofed-source. That means a huge amount of work and money for the
> world, without changing the endgame for attackers and victims at all.
> (See BCP38 and SAC004 for prior rants on this controversial topic.)
>
|
|
|