Anybody writing a system for a bank or the govt needs to have every line of code checked that it’s not doing something stupid with its crypto keys. That level of assurance would have caught this. But the process was defined too weakly.
FIPS-compliant key generator allowed key to be 4 ?
No, they just didn't check thoroughly enough
If you're talking about root certs then it's almost 350 currently trusted by at least one major operator.
If you include intermediates, you're talking more than 3,600!
They instead place the burden on individual webmasters again to actually verify that nobody has been falsely issuing for their domains. There are also some new vulnerabilities about CT logs who might be malicious.
Do you have any info on the malicious CT logs? I'd be interested to read something on that!
Good: trustworthy Often bad: trusted
Mozilla et al. could claim trust for Microsoft and then MS would be an intermediary for Mozilla. There is a long history of sketchy intermediaries like GoDaddy and others that root certificate providers like Mozilla would block at times due to abuse.
This leads to users, usually ones that are not that technically savvy, seeing 'insecure' warnings on a page that actually offers HTTPS. ..but since the root servers no longer accept them as trusted, everything that GoDaddy supported, and every intermediary (child) cert which they approved would no longer be trusted and you would see a non-secure warning.
they violated that trust.
I mean specifically for the use case of the browser warning the user if there is a MITM between them and e.g. their bank.
Then at the very least one of the CAs leaking isn't automatic compromise, as leaking the key still doesn't make you insecure, that would also require intercepting and changing DNS records
This really reduces how much we need to trust the CAs, because we can detect any untrustworthy actions after the fact. Now detecting after it happened is too late. But it does mean that mistakes or malicious actions are much more expensive to a CA. In practice this has really reduced the risk, especially to those whom aren't interesting enough to burn a valuable capacity on. Which is the vast majority of people. Though perhaps if you count TLS traffic weighted by importance that count is different.
When a certificate is logged to CT, you get back an SCT, and the issuing CA will normally include that in the certificate. The browser will then accept this certificate as it has the correct SCTs (there are always at least two).
The attacker issued certificate hasn't been logged, so can't have an SCT, so won't be accepted by the browser.
We can't say that no certificates have been issued by an attacker. We can say that no certificates have been issued by an attacker that a modern browser client would accept.
In the long run, fixing bugs is almost always better than working around them. DNSSEC is a bug. So are CAs. We can and should fix both.
He is not arguing that DNS security cannot or should not be improved; in fact, he explicitly states the exact opposite.
It's going to settle into general usability at just about the time cryptographers deprecate ECC entirely!
"As a rule, strong feelings about issues do not emerge from deep understanding."
And if we have a secure DNS, then CAs are completely redundant. I'd much rather trust a handful of domain registrars than a handful of domain registrars, plus 100 random questionably competent organisations all over the world. Especially when any one of them can generate keys for every domain on the planet.
A confidential DNS has real value. Without it, ISPs actively monitor customers and sell analytics about usage upstream; there are other problems, but virtually every US user faces that one. It's hard to imagine wanting to trade confidentiality off.
A high-integrity DNS is a more dubious proposition. You'd obviously rather have integrity than not, ceteris paribus, but we have effective mitigating controls for DNS forgery, so you might imagine trading it off.
Availability also sounds like a no-brainer, until you remember that almost every other component of the networking stack also has availability issues. You might not want to trade anything at all to get a more highly-available DNS, if you're going to be just as susceptible to DOS attacks because the current DDoS meta is application-layer anyways.
There are a bunch of different approaches to securing the DNS, and they make different tradeoffs.
DoH focuses on confidentiality, and has bank-shot benefits to integrity (because it breaks forgery attacks from on-path attackers). Confidentiality is its primary purpose and it trades basically everything else off.
DNSSEC makes the opposite tradeoffs: it's exclusively for integrity, provides no confidentiality, and highly prioritizes availability (that's why it has elaborate authenticated denial systems).
Depending on what you want to achieve, "secure" DNS can make sense and actually get deployed and used, as DoH is, or it can make almost no sense and see almost no uptake.
Which might still be better, if only because it limits the surface area.
shudders
(1) We're also rearchitect the way all DNS is done so that every lookup from every phone and laptop is fully recursive, so that everyone validates DNSSEC chains instead of relying on the AD bit that cable company DPI devices switch off.
(2) People will lose all attachment to their current domain names and simply migrate to TLDs that have policies they agree with, rather than .COM and .IO, which are under the demonstrated de facto control of the NATO IC.
There's no such thing as a "trust store" in practice. To be "trusted" you just need to demonstrate you have control over a DNS TXT record, and we don't need a special "store" or intermediary for that.
Certificate authorities are an artifact of a bygone time and an entirely different model of internet infrastructure.
(Moving the PKI into DNS does not remove it, it just moves it around.)
Better in DNS though. You could have certs mirror the structure of DNS. Install a single root signing key for the top level DNS registry on client devices. Then you can query that to find out the signing keys for .com, .net, .au, etc. And continue from there.
One big problem with the CA system is that any CA - even the most incompetent - can sign certificates for any domain. If trust was moved to DNS, there would only be a single organisation that could forge certificates for any given domain. Using 7 as a private key? What a joke. The CAs aren't worthy of trust.
We already have to trust the domain name registrars anyway, since CAs query them to figure out if you own a domain before signing a certificate. In total, removing CAs would not only simplify the system. But it would allow scoped signatures. And we'd end up needing to trust far fewer actors to have a secure internet.
Is this not what CAA records were intended to solve? It seems like in practice they're only used by CAs to decide if they can sign a cert for a given domain, but it seems like a client could use it to determine if a server cert was from the correct CA.
1. A domain would have to keep the CAA records for a CA in place to keep using the certificates from that CA, but that means continuing to authorise new issuance too. Right now, I can remove the `letsencrypt.org` value to stop them from issuing new certificates for me, but I can keep using any certificates I have until they expire.
2. The client would need to have support for this new DNS RR type.
3. The client would need a secure way to query DNS, which is not widespread.
I infer from the wording around there and elsewhere in the RFC that this is mostly because someone could switch issuers but still serve valid certs from the prior issuer, and there's no way an RP would have a historical record of which CAA values were in effect when to be able to determine if the issuance was valid or not.
I think the idea that CAs are uniquely incompetent is probably incorrect.
(Half joking).
The dependency of "accetpable", i.e., not self-signed, TLS certificates on DNS, i.e., a domain name in a TLD created by "ICANN", is funny when one considers that the traffic to authoritative nameservers is still unencrypted. It stands to reason that DoH and other "accepted" forms of "DNS security" are only to stop ISPs from stealing Silicon Valley's surveillance advertising racket. Neither is "DNSSEC" providing the user with any real "security"; it's protecting a monopoly. The "security" is against anyone who might try to use domains names not blessed by "ICANN"
Indeed there's no need for CAs just as there is no need for ICANN
Scan a QR code when you open the bank account, add it to the keys you trust as authorities on financial things. When your browser runs accross data tagged "financial" it checks the trusted keys in that domain and renders it only if it was signed by a key that is trusted in that domain (the domains prevent your bank from abusing that trust by causing you to see political ads or some such).
If you ever see something that you suspect is malicious, you untrust whichever key signed it and take it up with whoever asked you to trust their key. If you verify it's malicious, gossip the bad keys to your friends so they can distrust also.
If confidentiality is required, well you already have a public key that you're using to verify content, then the content can say: "reach us at 196.7.3.45" and then you encrypt communications to that address with the same public key you use for validating content.
Or maybe they'll specify, in the content, that you should use a different key for that, but either way the chain of trust is preserved.
This would of course all be protocol level stuff, handled by the browser, not a human. They just have to maintain a list of keys they trust.
Um, I don't think you understand this problem near as good as you think you do?
>A man in the middle can pass the content along or they can refuse to do so but they can't forge a signature.
So where do you get this signature exactly so they don't MITM you the first time?
> well you already have a public key that you're using to verify content,
Who what where when why? Where did I get this public key? Who provided it? Is this my public key or their public key? How do I trust it?
>They just have to maintain a list of keys they trust.
So you've solved exactly nothing.
That's always going to depend on why you're trusting them in the first place. If somebody handed you a business card the key should be on the card. If it was a recommendation from a friend you should use whatever key they use.
If you're expecting to just type random IP addresses into your browser until you hit something and then be told that you should trust what you see... Well that's not in the cards because you shouldn't trust what you see in that scenario.
We already don't type in URL's, we send links to each other. It really wouldn't be so difficult to change the UX so that when we delegate trust in that way it's public keys that are being trafficked instead.
> So you've solved exactly nothing.
Removing untrustworthy third parties and the need to revoke trust in them on the user's behalf is the solution. Users don't know what a CA is or how they should evaluate its trustworthiness. We need a system where they're instead evaluating the trustworthiness of things they understand, like other people.
When they get burned they should have the ability to immediately revoke trust in whoever burned them. This thing we're doing where we expect them to wait around while some nerd pushes the updated list to them and to blindly trust that that nerd isn't curating that list with ulterior motives is totally bonkers.
RFC 7469 appears to be more geared towards service providers attempting to protect their users. Laudable, but we're still assuming we know something about who the user deems trustworthy, which I think is presumptuous.
It's one thing to suss out cases where somebody is lying about their name, that's pretty cut and dry. But ever since web2.0 there's no longer much of an association between the hostname and the trustworthiness of the content. If we instead provided a means of validating the content's provenance it wouldn't much matter which host was involved in its delivery.
The only 'real' problem though with this approach is it requires a trusted path for the bank to get the "JP Morgan Chase root CA cert" into my hands (like a QR code they hand me physically). Serving it up over http: or over an unvalidated SSL context at first use seems to defeat the purpose since I could be being MitMd the first time I hit chase.com. In practice most people would be angry that they couldn't use the bank's website if their new phone or PC didn't have the certificate yet, and if places start advertising their cert QRs everywhere, it will normalize the idea that you add a CA certs all the time, leading to CA cert QRs being on billboards and bus stops and eventually fraudulent ones would be snuck in that way.
We should push this into the application layer, so rather than scoping the keys to domain names let's scope them to something relevant to whatever the user authentically trusts. Something to do with their intentions for using this app. Because most users don't even know what a CA is, but they understand that most of the time they'll need to trust somebody. So let the app decide what that's going to mean because those dynamics are always going to depend on the situation.
So the user (or OS) would pass an object at runtime to indicate which keys they want the process to trust for this session. Typically it'll be another human or a company, not a server name, but I suppose it could also be a device. Something that can guard a key pair and be identified by its ability to produce valid signatures. That way you're just not relying on globally unique human friendly names at all. Doing so puts you in a cursed corner of zooko's triangle.
Users can assign a pet name for whoever they're trusting at the time they're configuring that trust since that's the moment they're best able to scrutinize the trustworthiness of this individual or company or device. Not later on when they're installing software updates and have no context for the decisions they're making.
This way your application can work over alternative transport layers: carrier pigeons, lobbing an SD card over the border wall, whatever, and doesn't break just because the other party has a different name on the new transport. Relevant for when the internet goes down and you still want it to work with other hosts on the LAN or the local mesh or whatever.
'Cos no scammer would ever be so sneaky as to leave off the tag... /s
> it up with whoever asked you to trust their key
'Cos no scammer would ever pretend to be that person... /s
As for tagging... We could use something like color to indicate domain. So if your well trusted plumber is giving financial advice maybe it shows up, but not in the "financial" color? Idk it seems like a solvable UX problem.
I genuinely can't say I secured a PC, when it needs to phone home for a configuration at this point.
We are most likely over the line for needing to airgap a personal PC.
Edit: > Every time you access your bank on different devices normalizes it so that visiting a typo domain would show the dialog and many would just click through.
Show the dialog? What dialog? There is no dialogues here, you cannot login to the bank unless you've verified the connection. You do it with your phone, then you can propagate the trust from there to other devices if needed.
You can't walk back from the existing expectation and ease of use we have today. It's just not going to happen, people will opt for the current path because it's easy and seems good enough to them.
Most normal people don't even know this whole thing is going on. They don't know the difference between http and https other than "it's secure".
If we want to improve on this, it has to come with the current level of ease of use at a minimum.
OR it has to be a situation catastrophic enough. I don't think this one is, but it's hard to be optimistic for the future
The current level of ease is not being achieved securely. If it's not possible to do so, we should walk it back.
This works great for something that are obvious. "Hey, this plumber was good and cheap".
The problem is this completely and totally breaks down where things are obscure. When things turn from "reals" to "feels" the amount of manipulation a bad actor can perform is great.
I'm trying to do more than that. If we validate claims made by the content as anchored in the user's trust graph, we don't have to care which server it came from--it's trusted for different reasons. Are you saying we shouldn't try just because it's hard?
Trust doesn't scale, and the internet is something that operates at scale.
All of the systems you're talking about have already existed and been tossed by the wayside. People could always have exchanged things like GPG keys, and yet here we are in a world in which we don't.
The vast majority of your users do not want to manage trust. They want it to be taken care of. Almost no one gives two shits about a trust graph, except maybe nerds like you or me. Exposing the average person to these concepts doesn't increase trust. It just makes the world more confusing for them.
This starts to delve into the monkeysphere and how many 'close' relationships people can form. If we have just a few things we trust it might work. Once you get over 15 or so it starts breaking down, and at 100 it's out of the question. Again, trust works on our evolutionary monkey brain that is used to a small tribe and systems requiring personal trust do not scale past that.
Trust graphs are worthless when they are built on a house of security lies. It's easy to get kicked out of them, but nearly impossible to secure your systems to the point you can keep attackers from stealing them and pretending to be you.
We need to recognise that is impossible. Making getting into a bank account easier for the owner does so for everyone else too. And also makes it easier for the bank to ditch the secure fallback - a building.
And ask why vendor-indepedent trust shops aren't sprouting in every locale. Answer: same security problems.
We are well and truly doomed to living in a scammers' paradise.
And also, how is my bank supposed to safely generate and distribute a key that we can exchange securely if an organisations who's primary purpose to generate these keys couldn't even manage to do so.
I have plenty of other services I use too. Suddenly my phone company, doctors, supermarket has to create and distribute keys for me to go around collecting so that I can securely talk to them and we have to do this in a way that stops anyone from swapping those keys out before they get to me.
I mean the current system isn't perfect, but it's a Utopia compared to that.
It does seem to lean on the physical bank-front being trustworthy (no evil clerks).
If we’re meeting physically to set up connections, we could even use something like a one-time-pad, and be information-theoretically secure. How many bits does your bank really need to send you securely anyway?
Like it seems your disagreement is that you're pointing out there are systems today that trust WebPKI CAs but don't validate CT/SCTs. I'd agree that that's an issue and I want those systems to join the world where CT exists.
As I said, in a world with CAA records and CT logs, this isn't an issue. If your CA wants to be in root trust stores, you have to put your certs in CT logs. CAA records are "advisory" in the sense that we mandate that root-trusted CAs obey CAA records and that they write cert issuance to CT logs, so a trusted CA that violates CAA records has to tell on itself in a very detectable way.
Refs: Part 1: https://scotthelme.co.uk/impending-doom-root-ca-expiring-leg... Part 2: https://scotthelme.co.uk/complexities-chain-building-ca-infr... Part 3: https://scotthelme.co.uk/cross-signing-alternate-trust-paths... Part 4: https://scotthelme.co.uk/building-certificate-chains/
There's also the Let's Encrypt root migration that was postponed due to legacy devices: https://scotthelme.co.uk/lets-encrypt-postpone-isrg-root-tra...
Right now CT support is rough for things outside of browsers; it's a pretty fair bet that if you pick up a command line tool or library, it is not checking SCTs, and that makes those workflows vulnerable. If we flipped that, and the average command line tool or library did validate by default, it would dramatically alter the risk calculus for attackers.
I agree that more SCT validation across the ecosystem reduces the value of a mis-issued certificate to an attacker, but a lot of value still remains.
If 90% of clients did SCT validation, an attacker can still succeed against the 10% that don't, there's no herd immunity.
> In a world [where] CT logs and CAA records [exist]
And we are in that world. CT logs and CAA records exist. They are around. What you are implying you said is:
> In a world with CT logs and CAA records [and everyone/everything reads and validates them]
We are not in that world, and we probably won't enter that world for the next 15 to 20 years because we are also in a world where folks expect networked devices to be able to communicate (mostly) securely without constantly communicating with a centralized set of clearinghouses arbitrating "what is secure".
As we are discovering, our flawed systems may need broader rethinking, especially if we want secure communication (with all the epistemological ball of yarn that comes with it) without constant total centralization, which seems to be the approach-of-least-resistance lately.
So you create more surface area for vulnerability? We might already be at or close to the sweet spot. Security is hard.