One way is for the hijacker to simply peer with himself. The hijacker has an existing peering arrangement with, say, AT&T. He then tells AT&T that he will be transit for ASxxxx advertising XYZ routes, by dint of a cheerfully forged LOA. Once filters have been updated, the hijacker advertises the space to himself, and then from thence to AT&T.
It's no great trick getting peering set up. Just fill out a ten-question BGP app and pay a one-time fee of maybe $100, and you're done. -mel beckman > On Jun 5, 2017, at 3:56 AM, Ronald F. Guilmette <r...@tristatelogic.com> > wrote: > > > The more I know, the less I understand. > > Maybe some of you kind folks can help. > > Please explain for me the following scenario, and how this all actually > works in practice. > > Let's say that you're a malevolent Bad Actor and all you want to do is > to get hold of some ASN that nobody is watching too closely, and then > use that to announce some routes to some IPv4 space that nobody is > watching too closely, so that you can then parcel out that IP space > to your snowshoe spammer pals... at least until somebody gets wise. > > OK, so you pull down a copy of, say, the RIPE WHOIS database, and you > programatically walk your way through it, looking for contact email > addresses on ASN records where the domain of the contact email address > has become unregistered. Say for example the one for AS34991. So > then you re-register that contact domain, fresh, and then you start > telling all of your friends and enemies that you -are- AS34991. > > That part seems simple enough, and indeed, I've seen -this- part of the > movie several times before. However once you have stepped into the > identity of the former owners of the ASN, if you then want to actually > proceed to -announce- some routes, and actually ave those routes make > it out onto the Internet generally, then you still have to -peer- with > somebody, right? > > So, I guess then, if you're clever, you look and see who the ASN you've > just successfully hijacked has historically peered with, and then you > somehow arrange to send route announcements to those guys, right? > (I'm talking about AS206776 and AS57344 here, BTW.) > > But see, this is where I get lost. I mean how do you push your route > announcements to these guys? (I don't actually know that much about > how BGP actually works in practice, so please bear with me.) How do > you know what IP address to send your announcements to? And if you are > going to push your route announcements out to, say, the specific routers > that are run by AS206776 and AS57344, i.e. the ones that will send your > desired route announcements out to the rest of the Internet... well.. > how do you find out the IP addresses of those routers on those other > networks? Do you call up the NOCs at those other networks and do a bit > of social engineering on them to find out the IP addresses you need to > send to? And can you just send BGP messages to the routers on those > other networks without -any- authentication or anything and have those > routers just blindly accept them -and- relay them on to the whole rest > of the Internet?? > > I've read article after article after article bemoanging the fact that > "BGP isn't secure", but now I'm starting to wonder just how massively > and unbelieveably unsecure it actually is. I mean would these routers > being run by AS206776 and AS57344 just blindly accept -any- route > announcements sent to them from literally -any- IP address? (That seems > positively looney tunes to me! I mean things can't really be THAT > colossally and unbelievably stupid, can they?) > > Thanks in advance for any enlightenment. > > > Regards, > rfg > > > P.S. It would appear to be the case that since some time in April of this > year the "Bulgarian" network, AS34991, had evinced a rather sudden and > pronounced affinity for various portion of the IPv4 address space nominally > associated with the nation of Columbia, including at least five /24 blocks > within 168.176.0.0/16 which, from where I am sitting, would appear to belong > to the National University of Columbia. > > Oh well. They apparently haven't been missing those five gaping holes in > their /16 since the time the more specifics started showing up in April. > > And anyway, so far it looks like the new owners of AS34991 haven't actually > sub-leased any of those /24s to any spammers yet. Only the 190.90.88.0/24 > block seems to be filled, wall-to-all, with snowshoe spammers so far. > >
