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The MAPS SAL Project

The MAPS SAL Project. Or, how to encourage people to type “ no ip directed ”, or to ritually desecrate their Proteons. Avi Freedman, Net Access. The Problem (1). Tens of thousands of networks and subnets allow directed broadcast.

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The MAPS SAL Project

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  1. The MAPS SAL Project Or, how to encourage people to type “no ip directed”, or to ritually desecrate their Proteons. Avi Freedman, Net Access

  2. The Problem (1) • Tens of thousands of networks and subnets allow directed broadcast. • Thus, pinging to x.y.z.0 or x.y.z.255 can return a few, or tens or hundreds, of responses. • Combined with forged-source address, it’s trivial to attack someone you don’t like. A dialup line can generate tens or hundreds of megs of smurf.

  3. The Problem (2) • This has been the case for many years, but it became a big problem once IRC-weenies figured it out. • Tracking forged-source is very hard and requires (hi, Sean) intense and quick inter-provider cooperation. • ISPs get smurfed for having certain dialup users, and then get smurfed if they kick off those same users.

  4. The Traditional Solution • The traditional solution is to use CAR to rate-limit ICMP to given destination(s), on all border interfaces. • access 155 permit icmp any any • int f0/0/0 • rate input acc 155 90000 64000 64000 conf tr exc dr • or • access 155 permit icmp any 207.106.4.0 0.0.0.255 • int f0/0/0 • rate input acc 155 90000 64000 64000 conf tr exc dr • sho int rate shows you the progress...

  5. Traditional Solution, ctd. • Once you staunch the flow of crud, typically you can monitor the flow to see what smurf “amplifiers” are being used, and try to contact these amplifiers. • Problem - most of the ones out there either have no contact info, or have rejected fixing the problem already. • Still, some can be educated.

  6. Still, a Problem • This helps get useful work done if you have lots of excess capacity to peers and upstreams. • Unless you pay on a usage basis. • Some upstreams will help, some won’t. • Some upstreams can’t feasibly do border-CAR; some just want to charge you.

  7. The Ideal Solution • The ideal solution would be {for everyone} to install filters to prevent forged IP source addresses from ever being generated!!!!!!! • Big problem - too much load on wimpy VIP2/50s. • The SAL project addresses this less directly, both for routers and for hosts.

  8. The Plan (1) • SAL is distributing a black-hole feed of smurf amplifier nets via BGP. • Nets can be automagically withdrawn by entering their netblock after fixing their smurfiness. • People can use it as a BGP RBL, or preferably, to generate host or router filters with code SAL will supply.

  9. The Plan (2) • The web sites explaining the system will not be behind the SAL BGP feed, so people inside blocked networks can get information and even submit themselves for removal. • For new smurf amplifiers, attempts will be made to communicate with them and with their upstreams first. • SAL routes will not be listed publicly.

  10. Our Goal • The goal is to eliminate smurf amplifiers as a source of difficulty. Single-source UDP or ICMP slams are much easier to track down… • Short-term, we are seeking to get about 10% of the net using SAL; both web hosters and small and regional ISPs.

  11. How it Works • We have an online database of smurf amplifiers, with date entered, source, etc… • That ties into custom BGP code with some of that data represented in communities. • People participate by eBGP multihop peering with AS XXXX and setting next-hop to loopback. Routes have no-export set.

  12. Operations • Being run by the fine folks at MAPS. • Modest fee to the MAPS folks to participate (note: noone will be turned away for monetary reasons.) • Info requests to sal-interest@maps.vix.com; user questions to sal-users@maps.vix.com; NOC issues to sal@maps.vix.com.

  13. Problems with our Proposal • Some feel it is too punishing of the smurf amplifiers. Let’s all work towards educating customers, and work with them to fix their configs. • Major networks can’t adopt it because they serve too many smurf amplifiers. Anyone with a few thousand routes is probably hosting tens of them. We are addressing this by putting advertising ASs into route communities.

  14. Current Status • An operational site with an operational remove list and an operational feed, but the service is still in alpha, with < 10 sites. • Still in beta for participation, and are still working on legal documents. • > 4gb/sec of peak traffic using the service. • MAPS, with a few individuals as backup, to deal with operational issues.

  15. We’re Looking for... • Volunteers to assist with communication with smurf amplifiers before they are placed on the black-hole list. • Sites to use the SAL service, both small and large. • People to educate their smurf amplifier customers.

  16. We’re Looking for... • Feedback about smurf amplifiers being used in active smurf attacks. • Technical and policy feedback.

  17. Resources • http://maps.vix.com/sal/ • http://www.smurfblock.net/ • http://www.netscan.org/ • sal-interest@maps.vix.com • freedman@netaxs.com

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