Some critique here to back me up:
http://www.theregister.co.uk/2011/04/11/state_of_ssl_analysi...
How about instead of "SSL sucks!", you propose things that will (from your vantage point) improve SSL/TLS? What, so you don't like that Mozilla gets to dictate what all the trust roots are? Neither do I. But that is not one of the worlds great compute or UX problems to solve. Propose a solution.
It's a virulent misconception that the SSL/TLS security model depends on Verisign and Thawte. The only place in the whole model we have that dependency is your browser's configuration and that stupid dialog it shows when a cert doesn't check out. You can replace just those two parts and get virtually any other trust model you want.
There should be an explicit trust model where the service vendor ships your keys via an alternative side channel -or- a decentralised model which works on reputation or trust.
If it works, why do all the online banks use two-factor authentication these days?
Oh wait, there is the solution!
Psst. I've got news for you. adb56780a76686326612a1eb3c2b32053bbcf3d8. Ask a friendly vulnerability researcher what I probably meant by saying that. Guess what? More confident as a result of knowing it.
The rest of your comment is just pique. "Why do online banks use two-factor auth?" Because the alternative is passwords. "There should be an explicit trust model!" Go ahead and build it. Because TLS is well-designed, your new scheme will work just fine with it.
OK. Hey tptacek... :)
Mind elaborating a bit more, for those of us who don't happen to know any other vulnerability researcher who know what that hash means? The one vulnerability researcher I know had no idea what you were talking about.
(and a meta-comment; OMG, look how quick google is getting hackernews into it's index these days!)
Google doesn't turn up anything for that particular hash, though, nor did I see anything on the Matasano website, but I'm probably looking in the wrong places. I don't claim to be a security researcher, after all, even if I try to keep up to date.
Everyone knows the weakness with our current system isn't the protocol--it's the "trusted" roots. There are upwards of 100 organizations that have roots installed on my computer and each of them is an attack surface. And it's frustrating because if I'm Google, there's no way I can protect myself from these other firm's security flaws. That is the part of SSL/TLS that needs to change. Getting certs from DNSSEC would be a good start...
Again: the problem we have is that the UX and policy for HTTPS/TLS is brittle, so that it's hard to recognize and even harder to react to misconfigurations like "we're trusting CAs who are not trustworthy".
Faced with a policy and UX problem, someone needs to explain to me how a reasonable next step is to bake a new PKI into the core of the Internet.
There is a reason the IETF-types are so gung-ho on DNSSEC. But it isn't that they know it's a sound replacement for the CA system. It's that it bothers them that DNS- the- protocol is insecure. And that's fine (I think their solution stands a good chance of making DNS even less secure, but whatever). But they shouldn't get to piggyback on other security issues to achieve their goal.
I don't know about where you are, but even if I show up at my bank branch in person, they do two-factor authentication (card + PIN).
So card = identify. PIN = authenticate. That's not two factor.
The second factor would be an RSA key or a Digipass device.
That's used to authenticate the client. SSL's job here is to authenticate the server. So no, that's not a solution.
Besides, it's completely preposterous to claim that HTTPS is useless just because it's not enough for banks. Should each website send an RSA Token to each user?
(I don't suppose anybody's more up-to-date than me on if/when that'll be possible?)
Part of the intrinsic concept is that there's no authoritative identity service. Without an authority, you can't crack the authority.
Of course, this is just a sketch of an idea; it has the usual issues with peer to peer nets such as "evil majority wins". Plus, it has the potential to eat a good deal of bandwidth.
Regardless, I think it'd be a good idea to explore, probably in an academic setting first.
Now what?
I get that a false sense of security is worse, but we haven't yet figured out a better way that is still decentralized and works with a wide variety of user skill levels.
Because people who aren't expert users deserve security too. And they deserve functionality.
Well, SSL certainly isn't giving serious security in the "My ISP has been intruded" attack model.
You can't have both security and ignorance. If you really want to be secure, you're going to have to learn how to be secure, and then to know how to implement it.
--- edit. Not looking for argument. Looking for facts.
- This is my top hit for 'tls mitm proxy'
http://www.delegate.org/delegate/mitm/
It's dated as '06, however.
- I can install Fiddler (Windows https debugger) on my machine and read https traffic in the clear.
- A competent admin assures me that Websense can read https traffic. Couldn't really dig real detail up on the websense sites though. This chap suggests the admin is not wrong (search for corporate, it's toward the end): http://www.carbonwind.net/blog/post/Random-SSLTLS-101%E2%80%...
(Sigh). Fiddler pops the browser certificate warning when you use it; it's not breaking TLS.
You must just as productively say "my friend assures me AES is broken; maybe that's what Iran is doing." Just like your competent admin friend, there would be some reason for him to say that; it just wouldn't be relevant.
I don't have details on that, unfortunately.
http://security.stackexchange.com/questions/2914/can-my-comp...
It sounds pretty clear to me that with some work on the adversary's part and lack of checking of the certificate chain, TLS can be subverted.
Websense is used in organizations that distribute their own root ca key to the workstations behind it. The Websense machine is then given that root ca key and allowed to generate dynamic certs with it, so that a workstation with your organizational CA trusts them, but nobody on the regular inter webs will.
It's a really, really shitty way to do things, and effectively violates the trust of every user on your corporate network, but hey, they signed an agreement.
Use case 2: 40 year old man wants to use his laptop from starbucks for email. He has used computers for much of his life, but doesn't really understand how it works. He is on the road working 60-80 hours a week. He is taught to VPN in to work, but that is the extent of his understanding of security.
We're not talking about the use case 3: activist in Iran needs to communicate with compatriots. That is a much harder problem for which SSL is insufficient.
How do we set up a sufficiently easy system for use cases 1 and 2? Charging them $1,000 for a 2 day class in security is not going to work in scale, and nobody has yet written a security primer for dummies past the most basic of "don't give people your password and don't use your dog's name."
If Iranian activists want to trust Google for their sensitive email, all they have to do is track down Google's authentic certificate (by asking anybody outside of Iran to fetch it) and add it to their browser. Iran does not have the ability to break RSA. All they (apparently) have the ability to do is to con incompetent CAs into making new RSA signatures that some browsers are configured to believe.
We need a reputation based, distributed public key architecture.
I'm not being sarcastic. Your decentralized reputation scheme could very well be better than our severely compromised system of central CAs.
After you've done that, yes, it'll exist.
(Edit: Well, not really—have a look at the thread below.)
No cryptographic system is perfect.
The reality is that DNSSEC is a lot more fragile than even that. Even on paper (DNSSEC hasn't been deployed in the large successfully) it has gaps. For instance, did you know that as conceived in the standards, your browser isn't even meant to speak DNSSEC? Your browser doesn't run a full recursive cache --- in other words, your browser isn't a full DNS name server, which is why your computer has to be configured with the address of a name server. DNSSEC doesn't secure the leg between your computer and its name server.
"No cryptographic system is perfect" is a worthless sentiment. Only in the rarest instances do we know whether any system, from "hello world" to the Tacoma Narrows, is absolutely sound. Our job as engineers is to make determinations about which system is sounder. DNSSEC takes approximately the same architectural problems that X.509 has, rebuilds them from scratch in the context of a protocol that has for 20 years been riven with security flaws, and then still requires HTTPS/TLS to function. It is less sound than HTTPS/TLS.
I won't say more regarding this matter because you know a lot more about cryptography than I do. What do you think the best solution for this kind of problem is? PGP?
Back to DNSSEC:
What we do not need to do is take this extremely complex policy problem and bake it further into the Internet's infrastructure, so that only the greybeards at the IETF and the product managers at the five largest software companies in the world get to make choices about the Internet's security model.
Today's HTTPS debacle was brought to you by a policy mistake. When we originally deployed HTTPS/TLS, we did not understand enough about the forces acting on us to make totally safe policy decisions. What we need is more flexibility and more thought, not the exact same system we have now baked into one of the core protocols on the Internet.
Moving this into authentication/trust - how do you 'start' something like this at an Internet scale, assuming actively hostile, nation-state level players, such as in this article? It seems very chicken-and-egg for something as critical as encryption and protection of important content.
Just thoughts - it seems there's some big issues I'm missing though, such as initial seeding for 'new' users en masse. I can also see the code to keep track of all the trust vectors, etc. becoming VERY complicated...
Actually, for many people their bank seems like a good start for the trust chain; visit them in person and get the information you need for your trust root. And unlike the certificate companies, banks have end-users as their customers, not people who want certificates.
I'd consider subscribing to a few services that provided plausible claims to properly curate lists of ssl cert fingerprints for at least the majority of my security-critical domains. Even if it were just limited to the major internet properties (start with google/yahoo/amazon/paypal/twitter/facebook/etc), and add in major (and minor) banks, government institutions... If someone started up a service claiming to have telephoned the appropriate security people at those places and confirmed the cert fingerprints via non-internet/real-world-confirmable means, I'd certainly consider paying a few tens of dollars a year for that... Especially if it integrated nicely with a browser/os plugin.
But what we see is CAs authenticating cert applicants based on DNS (the ability to receive email verifies your "control" of the domain) and DNSSEC rooting to a Verisign-managed registry, just like the early days of SSL PKI.
That's exactly what SSL is supposed to do, and tptacek is saying DNSSEC has the same problems as any PKI, including SSL.
And more importantly, using DNSSEC without SSL, even if you know you have the right IP address you don't you're not being MITM'd.
note: Nothing against dnssec. I think it is an improvement, but I don't see how it would have helped in the situation in question.
We need a reputation based, distributed public key architecture.
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