The Internet's Biggest Security Hole Revealed

At DEFCON, Tony Kapela and Alex Pilosov demonstrated a drastic weakness in the Internet's infrastructure that had long been rumored, but wasn't believed practical. They showed how to hijack BGP (the border gateway protocol) in order to eavesdrop on Net traffic in a way that wouldn't be simple to detect. Quoting: "'It's at least as big an issue as the DNS issue, if not bigger,' said Peiter 'Mudge' Zatko, noted computer security expert and former member of the L0pht hacking group, who testified to Congress in 1998 that he could bring down the internet in 30 minutes using a similar BGP attack, and disclosed privately to government agents how BGP could also be exploited to eavesdrop. 'I went around screaming my head about this about ten or twelve years ago... We described this to intelligence agencies and to the National Security Council, in detail.' The man-in-the-middle attack exploits BGP to fool routers into re-directing data to an eavesdropper's network." Here's the PDF of Kapela and Pilosov's presentation.

SSL

I hope that all of those people who thought that getting users to blindly accept self signed certs was a good idea are starting to feel a bit stupid now...

An SSL cert signed by a trusted central authority isn't the absolute solution to all mitm attacks, but it's a whole lot closer to 'safer' than not.

Re:SSL

I don't think anyone thinks that self-signed certs should be blindly accepted.

What should be done is that self-signed certs should be acceptable, with the right handling. The way ssh does this is a good one; it alerts you when you initially connect, and throws up an extremely loud and nasty warning if the host's cert has changed from the last time you connect. This gives you the opportunity to verify the cert out of band if you should care to, and forces an attacker to hit you on your very first access to a given site.

Properly signed certs should be given higher priority, but a self -signed cert is still vastly better than nothing. The problem is that current browsers treat self-signed certs as being the worst of the three, when in reality they're much better than a naked HTTP connection.

Re:SSL

What should be done is that self-signed certs should be acceptable, with the right handling. The way ssh does this is a good one; it alerts you when you initially connect, and throws up an extremely loud and nasty warning if the host's cert has changed from the last time you connect.

That's great and all if you are an internet mechanic. But what if you just want to drive the damn car? For those people, who are the majority, those messages don't mean squat. Which means they have just as much a chance of picking the unsafe choice as they do the safe choice. So Firefox's solution has been make it hard to pick the unsafe choice. Make it so that you pretty much have to understand what's going on in order to even get the chance to pick the potentially unsafe choice. That seems like a pretty good policy to me.

Re:SSL

And you actually trust Verisign to be a primary signature authority for SSL? Why? They've cooperated in all sorts of stupidity, such as their temporary insistence on returning their own squatting domain as a valid entry for every non-existent domain in *.com, which was particularly nasty because they own the .com master servers. Do you really think that Verisign is that secure, and wouldn't cooperate in faking keys if a national security agency asked them to?

Re:SSL

They gave away Microsoft's private keys to someone who called them, a while back, in a rather infamous case that forced Microsoft to change their entire update system and their collection of "secure" sites. If they've done it once, it can clearly happen again, and the lack of publicity may simply be evidence of better media management. I'd be very wary of trusting them with anything and would be skeptical of any institution that relied on Verisign for any kind of critical proof-of-identity situation, though they're probably reasonable enough for personal certs.

Scary Much?

I find the thought of this genuinley scary. Correct me if I am wrong, but we would have to change the BGP protocol itself to fix this issue. That isn't going to happen anytime soon I reckon, so I guess there is nothing we can do but encrypt senstive transmissions and hope for the best.

Re:Scary Much?

Well, no. Large ISPs don't have to accept and forward routes from customers without verifying them. The solution to this is the same as preventing forged IP source addresses: stop it at the origination point. If you're an ISP with customer A and customer A starts advertising routing for an IP range they haven't previously advertised, don't accept the advertisement and forward it up the chain until you verify that they actually should advertise that route.

ESES is mature?

I've seen implementations of ISIS, and have deployed it myself in both IP and ATM environments. I've never seen an actual deployment of ESES, and I've never heard of one either. I've encountered ISIS adjacencies which don't form correctly, and come up as ESIS, though.

What hardware supports ESES?

Why this is not an issue:

BGP is almost always setup manually, at least when first configured. Network admins: DO NOT PUT UNTRUSTED PEERS IN THE ACLs. Joe smith running BGP on 123abcxxxhost.nl has no business being in your tables. If you're accepting adverts from any AS you deserve what you get.

The routing on the Internet has always been hierarchical: get updates from your upstreams. If they send you bad info you're SOL anyway, just like SSL certs and Verisign's root certs.

You can bet good money...

...that the good folks at the NSA (and/or the FBI, CIA, DHS, ATF, etc., as well as their counterparts in other nations) have been exploiting this for years.

Re:You can bet good money...

Yeah, but they don't need to poison BGP to read our data, since they have access by the Tier 1 providers and telcos to the actual photons on the backbone fibers. And of course legal immunity now that they passed that bill.

Nay, this would best be used against other countries, where the NSA actually works.

Re:You can bet good money...

If that's the British DHS, the American counterpart is Home Depot, and it should be obvious why they'd want to spy on people. This isn't really a security issue in the same sense broken encryption or the loss of unencrypted data is a security issue, though, so can someone icon and section to "mindless stupidity in protocol design" and/or add "Stone De Croze" to the tags?

I archive the talk

It was really cool, opened a lot of peoples eyes. Here is the archive, http://www.stits.org/fp/Defcon_16/ [stits.org]. Please don't flood it and only download it if you will use the info. I also took a ton of photos: http://www.flickr.com/photos/stits/sets/72157606608859399/ [flickr.com] Hope to see you all next year!

Wait, you're telling me....

Wait, you're telling me that they taught US intelligence agencies and the National Security guys how to attack the internet with man-in-the-middle attacks and exploits to fool routers into re-directing data to an eavesdropper's network...

and they didn't do anything to end the interception and eavesdropping problem???

I am shocked.

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If you have BGP peering...

There is a lot of harm you can do, least for a short while. But I have to say, this seems like a lot of FUD to me.

It is not trivial to get BGP peering, or to keep it if you are doing bad things. You will need one or more peers, and they will have to do this for you manually, not automatically. And (as I can attest) the AS prepending this attack relies on is a very blunt instrument.

Here are the troubles I see

- You need to be able to offer a better path from Point A to Point B than the existing Internet topology

- Unless you are Dr. Evil and can afford infinite bandwidth, this better path had better not also apply to a large chunk of the Internet, or you will get hosed with a lot of bandwidth (and, also, instantly stick up on the screens of NOCs all over the place) and

- If you are relying on AS prepends, these affect the path from you, but not directly the path to you. They are notoriously tricky and may stop working (because of changes in other people's advertisements) at any time.

So, to me, this is a might work sometimes for some people in some places, but probably not that well on a general basis.

The DNS cache poisoning sounds a lot worse, frankly.

A design: X says Y=Z.

I looked at this problem back in the early 1980s, when I was doing some work on TCP. I was trying to come up with a routing protocol that didn't require passing the same information around repeatedly, because backbone networks had very low bandwidth back then, and the existing routing protocols had either O(N^2) traffic or the "hop count to infinity" problem.

I came up with something called "Gateway Database Protocol", which was a scheme for passing tuples of the form "X says Y=Z" around. The idea was that any node seeing inconsistencies in "X says ..." would propagate the tuple back to X, revealing the problem to X.

This is enough to detect hijacking, but not enough to stop it. I'd worked out a scheme good enough to automatically correct erroneous data, but not one good enough to deal with the insertion of hostile data. The design goal back then was to guarantee that if the hostile site was removed from the network (perhaps forcibly), the system would then stabilize into a valid state.

That's not enough any more. But it is worthwhile considering that a routing protocol should have the property that if X's info is being faked anywhere in the network, X hears about it. BGP doesn't do that.

Re:Fun fun fud

Depends on how much you value your privacy.

Re:Fun fun fud

Depends on how much you value your privacy, Mr. Stephen P Wallagher of 4242 Green Leafy Forest Terrace, Springfield, Ohio 55538, Phone number 1-900-Hot Dude, alias "Lovestospooge."

fixed.

Re:Fun fun fud

Let's put it this way. Email right? It's delivered between hosts completely unencrypted. Imagine you could sniff all the email passing into, say, the white house.. would that be worth something?

Note, I've also given you the hint to prevent this bullshit from being a problem.

Re:Fun fun fud

Let's put it this way. Email right? It's delivered between hosts completely unencrypted. Imagine you could sniff all the email passing into, say, the white house.. would that be worth something?

Note, I've also given you the hint to prevent this bullshit from being a problem.

So we need to destroy the White House?

Re:Fun fun fud

Find me an internet provider not using BGP, and I'll show you a European who favours ESES. Yes, this is a major problem, BGP is (almost) the only WAN protocol anyone takes seriously and is the only one meaningfully deployed. I've worried about the possibility of BGP poisoning attacks myself, but only because we have a virtual monoculture and monocultures are generally a Bad Idea. They are dangerous animals.

Re:Fun fun fud

Monoculture is bad? Good thing Internet Explorer offers a different take on W3C standards...

I kid, I kid.

Re:Fun fun fud

Anyone have any insight as to how serious this ACTUALLY is?

Yes. Someone had managed to re-open the goatse.cx site again.

if you don't believe me, you know there is only one way to find out

Re:The man in the middle

How can a title including 'The Internet's Biggest ... Hole' not be kicked off with a goatse joke?

Re:The man in the middle

Yeah.. That's funny. Nice observation there...

Just one thing though... You sound like the teenage boys who always claim they want to grow up to be a gynecologist. Problem with that is that gynecologists usually see the worst looking, diseased, and nasty vagina. Not the good looking, sweet smelling, celebrity vagina.

So the guy who has all the internet porn is going to have quite a collection of goatse and things that will make you WANT to go back to looking at goatse.