North American Network Operators Group|
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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: owner-nanog@xxxxxxxxx [mailto:owner-nanog@xxxxxxxxx] On > Behalf Of Ben Butler > Sent: Saturday, February 02, 2008 12:17 PM > To: Paul Vixie; nanog@xxxxxxxxx > 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 188.8.131.52/19 and > has its route object in RIPE as being announced by AS13005. > My router at IX - BENIX say - announces 184.108.40.206/32 to > the router reflector their, the announcement from my IX > assigned address 220.127.116.11 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: owner-nanog@xxxxxxxxx [mailto:owner-nanog@xxxxxxxxx] On > Behalf Of Paul Vixie > Sent: 02 February 2008 17:32 > To: nanog@xxxxxxxxx > Subject: Re: Blackholes and IXs and Completing the Attack. > > > ben.butler@xxxxxxxxxxxxxx ("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.) >