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Posted by hkc 12 hours ago

Eight Bits of Trust: eMudhra's CA keys cracked in milliseconds(scotthelme.co.uk)
775 points | 383 comments
john_strinlai 8 hours ago|
new email from wayne, who is the original reporter:

"I've had more than a few emails asking on how this was discovered. The simple answer is: https://github.com/google/paranoid_crypto

Yeah, out of the box. CCADB was intended to be a quick corpus test before looking at subscriber certificates...

I've done a far more thorough check of all existing CCADB certificates, thankfully no more hits. Most of my time has been spent going over the basics that everyone assumed someone else had already done - a critical mistake to ever make near security.

So unless someone has significantly more computational resources or access to more cryptanalysis research the low-hanging fruit has been caught so far."

https://groups.google.com/a/mozilla.org/g/dev-security-polic...

TheJoeMan 7 hours ago||
I must say, if I was writing a password cracker, I probably would not think to actually start at "1".
tejtm 4 hours ago|||
Of course not, we start at negative zero.

https://en.wikipedia.org/wiki/Signed_zero

myself248 1 hour ago||
When I walk into a bar, I always ask the bartender for negative zero beers, just to check the place out, before placing my actual order.

I have not yet been accused of arson, but it's only a matter of time.

jasomill 1 hour ago||||
I don't know, when I run a password cracker, I always start with a brute force pass of very short passwords. Doing so adds a negligible amount of time to the crack, and its surprising how many short passwords you'll find in systems that permit them.
perlgeek 1 hour ago||||
You should start at "" or 0, not "1".
awesome_dude 2 hours ago||||
Welp, there goes that password
unrented7977 6 hours ago|||
Security through incredulity
lenerdenator 3 hours ago||
"Certainly no one is that lazy/stupid/ironic..."
renhanxue 8 hours ago|||
> https://github.com/google/paranoid_crypto

This repository was archived by the owner on Aug 19, 2026. It is now read-only.

I guess now that we've checked, nobody will ever make a mistake like this again so we don't need this anymore? :)

wildzzz 7 hours ago|||
Archive is a nice solution in between just letting it rot on the vine forever and deleting it. Leaving it open doesn't immediately signal to users that the codebase is no longer in development, youd have to check when the last commit was. And even then, that doesn't tell you much. Is this so simple of an app that there's really nothing to patch or upgrade for long periods? A python script that converts some legacy file format into an open one might effectively be complete, there's nothing left to add or fix and there's no real threat vector to exploit. Or is this a cutting edge app that someone committed daily for years but now hasn't moved in a year.

The one thing I don't like about archive is the inability to add new issues. If I encounter a new issue, I don't necessarily want to fork it and track the new issue myself. I don't want to take responsibility for the code, I just want to let people know so someone else can fix it if they care.

Aurornis 8 hours ago||||
Archived means it’s still available but signals that it won’t be developed.

Last commit was 2 years ago anyway.

0cf8612b2e1e 3 hours ago||||
I am sure the NSA will keep checking on our behalf.
fortran77 8 hours ago|||
You can still use a read-only archive.
commandersaki 6 hours ago|||
I'm guessing this is the code:

https://github.com/google/paranoid_crypto/blob/main/paranoid...

Scott_Helme_ 8 hours ago||
I have to be honest, that hasn't stopped me from trying!
jlmorton 11 hours ago||
In retrospect, having 100 trusted certificate authorities might have been excessive.
tclancy 11 hours ago||
In retrospect, not having a tiny competency check may have been an oversight.
oofbey 1 hour ago|||
Competence is difficult to check systematically. The problem is in the auditing process. The CA auditors check a much shorter list than an application that needs FIPS compliance. They just check that the CA is using a FIPS compliant key generator, and then basic things like following a logged, standard, multi person process.

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.

InsidiousWombat 9 minutes ago|||
> They just check that the CA is using a FIPS compliant key generator, and then basic things like following a logged, standard, multi person process.

FIPS-compliant key generator allowed key to be 4 ?

No, they just didn't check thoroughly enough

tclancy 1 hour ago|||
Oh for sure. And at the time these were done, I'd guess cracking them was a lot more work. But still. 4.
knowinow 51 minutes ago||
This key 4 was from a new ceremony, they must have hit the highest security key just recently and wrapped around.
Scott_Helme_ 8 hours ago|||
That really depends how you define "trusted certificate authorities".

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!

londons_explore 5 hours ago|||
Certificate transparency requirements effectively take the power away from certificate authorities.

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.

Scott_Helme_ 5 hours ago||
I agree this is a burden placed on domain owners, but who else can know if a certificate for my domain 'scotthelme.co.uk' was supposed to be issued other than me, the owner of 'scotthelme.co.uk'?

Do you have any info on the malicious CT logs? I'd be interested to read something on that!

jasomill 1 hour ago|||
Possibly CT logs revealing information about domain name and IP address spaces, or other information through implementation details, that might not otherwise be public.
londons_explore 1 hour ago|||
CT logs stapling proof, but then never actually including that cert in the log.
m3kw9 8 hours ago|||
How are they trusted if they can just generate any key they like in their back room?
swores 8 hours ago|||
"Trusted" means how people treated them, it doesn't mean the extent to which they deserved trust.
chrisjj 8 hours ago||
This.

Good: trustworthy Often bad: trusted

RALaBarge 6 hours ago||||
There are chains of trust which are established for SSL certs, centered around the idea that if we can believe Mozilla et al. that the server responding is who they claim they are. Up until now, that is good enough to establish the trust needed to accept the 2 keys in the connection are connected, and then a secure connection could be established to the host server.

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.

BubbleRings 41 minutes ago||
Which leads to users that are not that technically savvy learning to always click "Load it anyway!" and not think about it, even in financial management firms. Ask me how I know...
bigfishrunning 8 hours ago|||
That's the thing about trust -- in order to get into the root key store for windows, chrome, linux, etc they were trusted not to do that.

they violated that trust.

otabdeveloper4 10 hours ago|||
Correct, we only need zero.
sebzim4500 10 hours ago||
Interesting, what would be the alternative?

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.

InsidiousWombat 3 minutes ago|||
Zero would be hard but we could have signed CA cert put into DNS record and from that the org itself can create the certs for that domain.

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

rocqua 7 hours ago||||
In practice we have Certificate Transparency Logs that let us check whether a CA has issued a certificate for a domain you control without you asking them to.

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.

krackers 1 hour ago|||
How would certificate transparency logs have helped here though? If the private key leaks and anyone can mint a valid certificate that gets accepted, those logs aren't going to reveal it.
zaptheimpaler 3 hours ago|||
I think someone explained that only browsers and maybe some applications check the CT logs in the first place. Most applications don't, so someone can impersonate any URL an application connects to and the attacker doesn't have to publish to a CT log.
josephg 10 hours ago||||
Make dns secure and put certs / public keys in dns. Control over dns already gives you the right to get tls certs. It should just be connected directly. We don’t need CAs.
three14 9 hours ago|||
tptacek argues that DNSSEC is too flawed to actually do this:

https://sockpuppet.org/blog/2015/01/15/against-dnssec/

josephg 8 hours ago|||
He's right. DNSSEC is a mess, and we should fix that. We should fix that whether or not we delete CAs because CAs rely on DNS to verify that you own your domain. If DNS isn't secure, neither are CAs.

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.

chimeracoder 7 hours ago||
His argument is that DNSSEC is fundamentally broken, and you can't fix it via incremental improvements.

He is not arguing that DNS security cannot or should not be improved; in fact, he explicitly states the exact opposite.

tptacek 6 hours ago||
I don't have an objection to doing a different DNS security system, and in fact I like DoH a lot. You can do DoH all the way back from authority servers if you like, and that addresses domain validation without boiling the ocean with 1990s cryptography the way DNSSEC tries to do.
GoblinSlayer 7 hours ago||||
ECDSA was added to DNSSEC 3 years before that blog post in april 2012 (rfc6605).
tptacek 5 hours ago||
And then for the next 10 years APNIC wrote posts about how actually using ECDSA broke resolvers.

It's going to settle into general usability at just about the time cryptographers deprecate ECC entirely!

GoblinSlayer 3 hours ago||
They can be deprecated for confidentiality purpose, but DNSSEC doesn't use confidentiality.
tptacek 3 hours ago||
You're trying to argue that DNSSEC isn't exposed to HNDL attacks, so can use signature algorithms that CRQCs break. But that's neither here nor there: the approaching cryptographic research consensus is going to deprecate all ECC (and all RSA); yes, signatures aren't the priority for immediate removal, but nobody is recommending ECC signatures. The point is all this is happening just as ECC in DNSSEC may finally be stabilizing.
ranger_danger 8 hours ago|||
I have seen their comments across this site for a very long time. Unfortunately I do not respect or put any stock in what they say, because of how unbelievably rude and dogmatic they are, and always have been.

"As a rule, strong feelings about issues do not emerge from deep understanding."

icedchai 8 hours ago||
Fortunately, you can investigate this stuff for yourself and develop your own opinion. IMHO, DNSSEC doesn't actually "secure" much of anything. It can be disabled trivially by anyone operating a resolver. As I mentioned elsewhere, none of the major sites (FAANG) use it. What does that tell you?
GoblinSlayer 4 hours ago|||
Then propose a censorship resistant protocol.
ranger_danger 7 hours ago|||
Yes I'm not saying DNSSEC is or isn't good. I think a multi-layered approach would be best for redundancy.
tptacek 4 hours ago||
Wait. Hold on. It is either good or it isn't. If it's good, we should be using it (maybe in a layer cake, maybe a la carte). If it's bad, it should not be used anywhere.
shiandow 10 hours ago||||
Making DNS secure is not trivial though. In a way that's just moving the problem.
josephg 8 hours ago|||
A secure DNS is valuable whether or not we get rid of CAs, since CAs rely on DNS queries to verify domain ownership.

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.

tptacek 4 hours ago|||
"Secure" doesn't mean anything. A closer (though still imprecise) descriptor is the CIA triad --- confidentiality, integrity, and availability.

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.

GoblinSlayer 3 hours ago||
Security provided by CAs is TLS Web Server Authentication (1.3.6.1.5.5.7.3.1). CAs too are exclusively for integrity, provide no confidentiality and don't prioritize availability.
darkwater 8 hours ago|||
It seems a nice thing to have indeed, but domain registrars have already a history to cede control and bend to $GOVERNMENT. We have countries already trying to MiTM all their citizens by mandating CAs injection in every device under their jurisdiction, what would be the defense against this threat in a world where registrars hold the keys to TLS encryption for the web on the TLDs they own as root? I'm not that expert in this field so I really would like to learn if it's possible.
GoblinSlayer 4 hours ago|||
Government can compel servers in its jurisdiction to use a mandated CA. DNS would nicely compartmentalize it to the zone controlled by that government as opposed to the CA system where every random eMudhra CA has infinite reach.
shiandow 6 hours ago|||
Not that it isn't an interesting question but what's preventing them now? You can get a certificate for any domain you control. It is just really obvious if you abuse that power. Which shouldn't really change with DNSSEC I think.
vesinisa 10 hours ago|||
Isn't this what DNSSEC solves?
SAI_Peregrinus 2 hours ago|||
No, DNSSEC tries to solve one part of the security of DNS (security of records between resolvers) and does nothing for the security between the user and their DNS server. And doesn't even do a good job at the bit it tries to solve.
shiandow 9 hours ago||||
It should, though it achieves that goal by a chain of certificates not unlike CAs just tied to DNS. Like I said, it essentially just moves the problem.

Which might still be better, if only because it limits the surface area.

muvlon 9 hours ago|||
DNSSEC deployment has been anything but trivial. This APNIC post from 2024 estimated that about 1% of DNS queries were being validated via DNSSEC: https://blog.apnic.net/2024/05/28/calling-time-on-dnssec/. That's more than 25 years after the IETF first standardized DNSSEC.
tptacek 4 hours ago|||
I track DNSSEC adoption across the Tranco research list of top domains:

https://dnssecmenot.fly.dev/

giantrobot 8 hours ago|||
2107: The year of IPv6, DNSSEC, and The Linux Desktop.
jayd16 4 hours ago||||
So like, the cable company now controls the certs for most consumers?

shudders

tptacek 4 hours ago||
Yes. This is basically the DANE pitch. Subtextually, supporters argue that two big shifts will immediately happen:

(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.

braiamp 10 hours ago||||
That still requires trust stores to be distributed to the clients and some clients don't need that baggage on the dns. Also, dns is by default insecure, dnssec is a configuration nightmare
otabdeveloper4 10 hours ago||
> That still requires trust stores to be distributed to the clients

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.

woodruffw 9 hours ago||
The trust store refers to the collection of parties that ultimately verify the signed claim of your control over a domain, which might have taken the form of a DNS TXT challenge (or any other number of challenges). You still need it, because there would otherwise be a basic circularity when determining whether to trust a connection.

(Moving the PKI into DNS does not remove it, it just moves it around.)

josephg 8 hours ago||
> (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.

itintheory 6 hours ago|||
> One big problem with the CA system is that any CA - even the most incompetent - can sign certificates for any domain.

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.

Scott_Helme_ 5 hours ago|||
CAA records are only checked by the CA at the point of issuance, not by the client later. If they did, there are problems to consider:

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.

parasyte 4 hours ago|||
CAA records were never intended to be used by clients (Relying Parties), the RFC specifically prohibits them from using the CAA record to determine if the issuer was allowed to have issued the cert.

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.

woodruffw 8 hours ago|||
Why would I trust my domain registrar to maintain PKI? They don’t seem inherently better suited for it, and in various ways are more susceptible to meddling for e.g. ccTLDs.

I think the idea that CAs are uniquely incompetent is probably incorrect.

asksomeoneelse 10 hours ago||||
But how do you make DNS secure without CAs?
growse 10 hours ago||
You just have one big one on the root.

(Half joking).

josephg 8 hours ago|||
Better to trust 1 organisation than trust 100.
asksomeoneelse 9 hours ago|||
Is that a reference to the Root Key of DNSSEC?
1vuio0pswjnm7 1 hour ago|||
Perhaps browser fans will check the source code to verify that their browsers or operating systems using DoH ("Private DNS" or whatever they call it) check the certificates presented by DoH providers against CT logs

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

__MatrixMan__ 8 hours ago||||
Stop validating names, start signing content.

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.

diarrhea 8 hours ago|||
That solves integrity but not confidentiality. It does not protect against MITM.
__MatrixMan__ 5 hours ago||
It does protect against MITM. A man in the middle can pass the content along or they can refuse to do so but they can't forge a signature.

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.

pixl97 4 hours ago||
>It does protect against MITM. A man in the middle can pass the content along or they can refuse to do so but they can't forge a signature.

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.

__MatrixMan__ 2 hours ago||
> So where do you get this signature exactly so they don't MITM you the first time?

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.

tptacek 3 hours ago||||
You are describing key pinning. You have invented QR-code-based key pinning.
__MatrixMan__ 1 hour ago||
My intent is to provide users with the ability to revoke trust if in a source of information if they realize it is malicious, and to gossip that revocation among their peers.

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.

lokar 5 hours ago||||
So, have each domain run its own root CA (scoped to the domain), and have users trust them one at a time when they have cause to interact with them?
xp84 1 hour ago|||
In the modern day that's arguably fine, most users only interact with a few actual companies online (though many of them haphazardly use dozens of domains and dozens of unrelated certificates).

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.

__MatrixMan__ 5 hours ago|||
Yes to smaller scopes, with keys passed of during interactions that organically arise, preferably face to face, but maybe not always. No to making domain names be the thing that's being trusted.

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.

chrisjj 8 hours ago|||
> When your browser runs accross data tagged "financial" it checks the trusted keys

'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

__MatrixMan__ 4 hours ago||
Well if you find unsigned content, you should probably just not show it to the user at all.

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.

chrisjj 2 hours ago||
Anything relying on user recognising some tag colour seems like an unsolvable UX problem to me.
lukewarm707 9 hours ago||||
For me the complexity of anything connected to public internet is now over what I can secure.

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.

Ohentis 9 hours ago||||
I quite like how i2p does it. Public keys are part of addresses, human readable names are user defined and shared but static.
embedding-shape 10 hours ago|||
The first time you go to the bank, you do the "trust exchange" (maybe scanning a QR? People sure love that) that verifies future connections, similar to how you acquire digital certificates today when you deal with the government online and similar.

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.

bluehatbrit 10 hours ago|||
Not all banks have physical locations, not everyone has the ability to get to the ones which do.

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.

monsieurbanana 9 hours ago|||
> 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

__MatrixMan__ 8 hours ago||||
Presumably you had some reason to trust the bank in the first place. Maybe a recommendation from somebody you know? Get the key from them.

The current level of ease is not being achieved securely. If it's not possible to do so, we should walk it back.

pixl97 3 hours ago||
> Maybe a recommendation from somebody you know?

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.

__MatrixMan__ 25 minutes ago||
Agreed, but what would you propose we do about it? The current pki just washes its hands of the situation and restricts itself to only validating server names. Which probably made sense back when the people running the servers were also the authors of the content those servers served, but now it's a false sense of security.

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?

chrisjj 7 hours ago|||
> If we want to improve on this, it has to come with the current level of ease of use at a minimum.

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.

venzaspa 7 hours ago||
But my bank has no physical buildings whatsoever?

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.

chrisjj 5 hours ago||
Yes. As I said, we're doomed.
bee_rider 7 hours ago||||
That could be kind of interesting.

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?

whywhywhywhy 10 hours ago||||
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.
u8080 8 hours ago||||
Like...TOTP or FIDO2?
lirolero 10 hours ago|||
[dead]
BirAdam 11 hours ago||
or, perhaps you need more so that one being stupid doesn't effect so much.
epanchin 10 hours ago|||
Each CA is like a padlock locked in series with other padlocks. The weakest padlock is the only one that matters.
akerl_ 9 hours ago||
In a world with CT logs and CAA records, is that actually the case?
zbentley 8 hours ago||
Yes, because as we are seeing with this incident, plenty of things don’t check CT logs (and thus can still be hacked if CT isn’t published for bad certs), and CAA records are fundamentally advisory.
akerl_ 6 hours ago||
You said "yes" but then answered "no"?

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.

Scott_Helme_ 6 hours ago|||
I'm just not sure that I can see a world where all devices that rely on TLS/PKI are capable of CT SCT validation. Look at the issues we have around stale root stores still happening when we have validity periods of literally decades. Some of these clients out there simply won't ever be able to keep their trusted log store updated.

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...

akerl_ 6 hours ago||
Similarly to vaccines, part of the magic is that you don't need "all", you just need "most".

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.

Scott_Helme_ 6 hours ago||
For a scenario like this it doesn't help a given client what % of the ecosystem does SCT validation or not, all that matters is whether that client does it.

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.

lelandbatey 6 hours ago|||
You said:

> 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.

caaqil 10 hours ago|||
> perhaps you need more so that one being stupid doesn't effect so much.

So you create more surface area for vulnerability? We might already be at or close to the sweet spot. Security is hard.

Gabrys1 9 hours ago||
I would assume that the client would need to validate the certs against more than 1 trust path (for the comment to make sense)
jasonjayr 10 hours ago||
> It's fortunate that the steps required here aren't particularly complicated for the devices you can update, and the advice essentially boils down to 'update them'. The problem is the devices you can't update or update easily.

> Update everything that ships a CA bundle: your OS ca-certificates package, certifi, Node, Homebrew, and rebuild your container images once the base images pick up the change.

> Devices you can't update are the hard part. Routers, printers, TVs, appliances with frozen firmware will trust these certificates until expiry, which is July 2039...

Quick -- we need to MITM all the smart TVs so they can be jailbroken in one fell swoop!

__MatrixMan__ 9 hours ago||
Devices that are smart enough to talk to the internet but not smart enough to let the user install their own certs should not exist.
tonyhart7 8 hours ago||
"let the user install their own certs should not exist"

are you sure that this is not opening to more attack vector ?????

__MatrixMan__ 4 hours ago|||
Yes. We're giving the user the ability to protect themselves from the vendor.

Your logic only makes sense if the user is your enemy.

mitxela 3 hours ago||
I am the vendor and the user is my enemy. Fortunately I get to decide his capabilities and not the other way around, so I win.
JoshTriplett 2 hours ago|||
The device is in the user's possession, so you'll lose eventually, it's just a matter of how long it takes.
esseph 3 hours ago|||
Oops, claude just cracked your system!
andix 4 hours ago||||
You can even install your own certs into the golden cage (also known as iPhones).
LtWorf 8 hours ago||||
Users aren't supposed to be considered an attack vector. I don't care what the advertisers think.
axus 8 hours ago|||
The infected devices on the LAN are an attack vector, though.
mapontosevenths 7 hours ago||
If I want my IOT garbage to be infected that's between me and my local botherder.

The vendor loses the right to decide how my things are used the minute they take my money.

mitxela 3 hours ago||
Not in the EU. If devices you made get hacked in the EU and you have a business presence there, you're liable for the resulting damages under the Cyber Resiliency Act. If you don't notify the authorities promptly upon discovery, you might also be criminally liable.
esseph 2 hours ago||
What if your company doesn't exist anymore, and you have checks billions of devices out there that won't be getting firmware updates?
antonvs 7 hours ago|||
Users are attack vectors in one of the more commonly successful attacks: social engineering.
gus_massa 5 hours ago|||
Like: To verify you are human, clik on the two ducks and install this new certificate.

Bonus points if it's during a fake job interview.

antonvs 4 hours ago|||
Absolutely. "To access our secure site, install this certificate as follows..."
mitxela 3 hours ago|||
I did a job interview in a VM once and my legitimate accounts on some platforms got banned for using them in a VM. So you can't even protect yourself.
no-name-here 3 hours ago|||
> my legitimate accounts on some platforms got banned for using them in a VM

Which legitimate accounts get banned for use in a VM?

That seems like an incredibly important thing I should know as I use legitimate accounts in VMs.

Y_Y 2 hours ago|||
Bullshit. How would a website even detect a VM?
ruszki 5 hours ago||||
Yes, however, this causes people who know what they do suffer because of people who don't. My question is whether this affects innovation, because the same thing at different places definitely does, and we actively fight against this exactly to help innovation.
LtWorf 49 minutes ago|||
Right. Let's no longer sell computers then.
tempfile 7 hours ago|||
Which is better - two attack vectors that can be mitigated by an expert, or one attack vector that can't be mitigated by anyone?
panarky 5 hours ago|||
It's easy enough to apt upgrade, and curl shows it's not vulnerable.

But what about python pip and node and bun which bundle their own certs?

And then you'll have a compiled binary like Claude Code, which was built with bun, and has its vulnerable certificates bundled in, ignoring the system certs.

Scott_Helme_ 4 hours ago||
Yep, it's a long tail. Anything that ships it's own CA bundle will ignore whatever you fix at the OS level. Those bundles are generally root-only and don't have revocation checking, so they can't block a bad intermediate cert.

The fix can only come from the tool shipping an updated bundle, or if there's some way you can point it at the OS store once that's updated.

ezoe 9 hours ago|||
These devices are already very weak and many of them even do non-TLS updates with no signing check anyway.

If it has been so weak already, it can't be weaker.

Sayrus 9 hours ago||
Not always true. I have IoT devices where a valid certificate is useful because the original host doesn't exist anymore and the certificate isn't pinned.

Flashing the devices require direct UART/USB access which may involve soldering, if it even exists. This leak is gold for those because these devices will never get an updated CRL.

happyPersonR 5 hours ago|||
If you just take them offline you can do this without having to rush.

Just change your WiFi password, don’t give them the new one and don’t update them lol.

junon 5 hours ago||
You can't hardly use the TVs then. I've seen TVs that don't let you use the HDMI port without it being connected if you have a streaming dongle connected. Hopefully that practice has mostly died off now (Samsung used to do this on some models, iirc), but it's still a risk and only kicks the can down the road a bit.
happyPersonR 2 hours ago|||
Yeah those devices also need to be “opened up” as it were. Some of them already have been. Just think about it like fermented whiskey. Leave them alone for a month or two until they run an opensource firmware you control.
geeio 3 hours ago|||
I have a terrible LG smart TV (that seems to connect to WiFi that is not mine), but I would instantly return a TV that did this.
Scott_Helme_ 8 hours ago|||
Just imagine how much stuff you're going to be able to MiTM now!!
justincormack 9 hours ago|||
Some of them seem to do some cert pinning
mschuster91 10 hours ago|||
> > Devices you can't update are the hard part. Routers, printers, TVs, appliances with frozen firmware will trust these certificates until expiry, which is July 2039...

The interesting question is, how many of these devices will have the compromised CA root certificate in place?

Oh and another thing is problematic, many a Java app ships with its own keystore.jks if it needs to trust some privately hosted endpoint, and that keystore.jks may or may not contain the compromised CA root certificate... updating the OS will not catch this kind of stuff.

cromka 6 hours ago||
> how many of these devices will have the compromised CA root certificate in place?

I have two Google devices at home and both are compromised still. If Google can't handle pushing out a quick cert chain update, then I truly doubt other manufacturers can.

londons_explore 5 hours ago||
I'm rather surprised google doesn't require cert pinning for all connections to any google server....
binyu 10 hours ago||
[dead]
irusensei 8 hours ago||
Okay hear me out. People are complaining about unpatcheable IOT device and thats indeed concerning. But can’t we use the bad keys to generate seemingly value certificates that can be used to jailbreak these devices?

EDIT: seems its already happening? https://x.com/otomir23/status/2112697830687047918

no_time 2 hours ago||
>yandex-station-lite

At last, russians got better at installing wiretaps. Reminds me of the old joke that goes "How do you know there is a soviet made bug installed in your home?

There is an extra wardrobe."

Scott_Helme_ 8 hours ago|||
Yeah this is absolutely possible, and while they are a few good opportunities like this, it also means that someone else can decrypt all of your traffic in the same way.
reisse 8 hours ago||
Yeah, it's happening in the wild already. Seen more cases like that.
cromka 8 hours ago||
I really hope someone manages to root the Google Home speakers. Been waiting for ages to be able to repurpose them for Home Assistant integration!

EDIT: just whipped up a quick hacking session with DeepSeek and, indeed, Google hasn't updated the cert chain yet on these devices, I am sniffing everything with MITM! Let's see if I can put that to use and gain root. At the very least, a mock endpoint server is possible now for use with Home Assistant.

WalterGR 12 hours ago||
Related: https://news.ycombinator.com/item?id=50166579

“eMudhra intermediate CA compromise” | 947 points | 19 hours ago | 408 comments

gagan2020 11 hours ago||
"Importantly, none of the affected intermediate CAs were deployed in production, with the exception of one. Furthermore, none of these intermediate CAs, including the one deployed in production, have issued any end-entity certificates. This has been confirmed through our internal analysis and corroborated by publicly available Certificate Transparency records on crt.sh."

This statement is more discerning than anything else. It raises question about why this certificates exists in first place if not deployed since 2025. Is it deliberate attempt to do compromising of system?

In recent times, Indian Government is becoming quite rogue and don't follow the said procedures. So, it might be related to that as well.

_justme 22 minutes ago||
https://bugzilla.mozilla.org/show_bug.cgi?id=647959
bombcar 12 hours ago||
Of COURSE it's easy to crack, 4 isn't even prime!
DavidSJ 11 hours ago||
In their defense, they were probably targeting the Mersenne prime 2^2 - 1 and just made a typo.
throw0101a 11 hours ago||
> In their defense, they were probably targeting the Mersenne prime 2^2 - 1 and just made a typo.

There are two hard problems in computer science: naming things, cache invalidation, and off-by-one errors.

zapkyeskrill 9 hours ago||
Two, and only two?
throw0101a 41 minutes ago|||
Well:

    There are actually only two hard problems in computer science:
        0) Cache invalidation
        1) Naming things
        4) Asynchronous callbacks
        2) Off-by-one errors
        3) Scope creep
        6) Bounds checking
* https://news.ycombinator.com/item?id=38806257

Also: https://martinfowler.com/bliki/TwoHardThings.html

amoss 9 hours ago||||
You have almost understood the joke.
floydnoel 3 hours ago||||
two is off-by-one from three btw
motionlessveloc 9 hours ago|||
[dead]
wolfi1 10 hours ago|||
ok, it's joke. but for those who don't get it: elliptic curves don't need primes
joshuat 12 hours ago|||
It’s really impressive no one caught their three previous private key values
bcvvvy 11 hours ago||
I suspect they did but it wasn't publicised.
chompychop 10 hours ago|||
They should have gone with 57. Everyone knows it's prime.
bee_rider 7 hours ago|||
I wonder if anyone wants to over-analyze this joke to come up with the best candidates for the number? 57 falls too easily to the quick divisibility by 3 trick, IMO. (I realize over-analyzing jokes always makes them unfunny but we can pick the best number here and nobody has to know).
samatman 5 hours ago||
Me! I'm in!

Most-nearly-prime number under 100 is.... 91.

13 x 7. You've either memorized that or you're going to have fun deciding it's not prime. And if you did times tables up to 13, congratulations, you're special.

bee_rider 1 hour ago|||
I think 91 is a strong contender. Sejje has a way of working it out, but of course any small non-prime will have some trick to it.
sejje 2 hours ago|||
7 is an easy check, not because i did them up to 13.

because 10x7 = 70, i'm left with 21. everyone knows 21 is divisible by 7.

kachnuv_ocasek 10 hours ago|||
Alex? You're alive after all?
delibes 11 hours ago|||
https://xkcd.com/221/
lta 10 hours ago||
It's been a while since this one popped up. It's surprising how many of those doodles are surviving the test if times, in the midst unexpected ways
ohuf 7 hours ago|||
it doesn't have to be and it actually never is: this isn't RSA, it's an elliptic curve algorithm. if you'd have read the article, you'd have understood this
Zeetah 8 hours ago|||
The number 4 is very famous.

https://xkcd.com/221/

walrus01 11 hours ago||
Hey, that's the same combination I have on my luggage!
wowczarek 9 hours ago||
Good job the Earth doesn't have an air shield protected by this byte or we'd be Skroob'd.
amluto 7 hours ago||
For all that DNSSEC is crap, DANE would at least mean that a domain is only vulnerable to failures of the authorities relevant to the domain.

Meanwhile there are two less invasive changes that really ought to happen:

1. A clean way for things like curl and Python to start checking CT logs like Chrome does.

2. Name constraints. It’s long past time for the CAs of the world to have name constraints enforced. A CA that is not appropriate to use for .com should not work for .com. A CA that is not appropriate to use for .ae should not work for .ae. And the CA/B Forum should should requiring that all newly approved roots and all newly signed intermediates have appropriate name constraints.

alphager 6 hours ago||
1 already exists. You don't check the ctlogs; the ctlogs as their signed timestamp to the certificates. All you need to verify that a certificate has been published is to verify the timestamp signatures.
Scott_Helme_ 6 hours ago|||
1. They could do this now, the implementation exists publicly, but I think it would be better at the OS level like upki for revocation: https://discourse.ubuntu.com/t/addressing-linuxs-missing-pki...

2. I don't think such constraints would really work. My company might have 4 domains on different TLDs and then end up needing to use 4 different CAs. Geography doesn't really apply on the Internet.

amluto 2 hours ago|||
> I don't think such constraints would really work. My company might have 4 domains on different TLDs and then end up needing to use 4 different CAs. Geography doesn't really apply on the Internet.

I'm not sure it needs to map out this way. In the last few years people have gotten used to the idea that ACME means that the client interacts directly with the actual CA, but there's another model that at least used to be widespread: certificate brokers. Right now, I tell my ACME cliejnt to get me a Let's Encrypt certificate, and Let's Encrypt validates my request and makes it happen.

But what if I instead tell my ACME client to talk to a broker? The broker would arrange with various CAs for whatever portions of the overall namespace it supports, and it would give me TOS that those CAs find acceptable. And it would then forward my requests to appropriate backend CAs, and those backend CAs would (and would be required to by CA/B rules) validate my request. And I'd get a cert without particularly caring who the backend CA is.

The root stores would treat the backends as fully responsible for validation.

I don't know whether the current ACME model actually supports this very well. The tricky bits I can imagine mostly involve ACME account identification, CAA record details and dns-persist-01. If I authorize my ACME account (held with the broker) for my domain, the backend needs to be able to validate, in a manner that the broker cannot forge except to the extent that it's unavoidable. So if I have account 12345 (just an identifier), then I think the backend should be able to trust the broker's assertion that the client really did convince it (with replay protection) that it's the client for account 12345. But if I have an account where the account itself indicates a public key, then the broker should not be able to forge it.

In any case, I think it's vaguely ridiculous that, right now, the UK government has essentially no say in whether Let's Encrypt may issue certificates for .gov.uk domains. (This is just an example.)

Parodper 3 hours ago|||
> My company might have 4 domains on different TLDs

Your CA would have a root cert per TLD. Alternatively, we get rid of non-cc TLD (and leave ccTLD only for truly geography-bound organizations, like governments).

Scott_Helme_ 3 hours ago||
Wouldn't that be almost 2,000 root CAs?

Also if it's the same CA operating a bunch of different roots for different TLDs, they're likely to just make the same mistake that impacts them all. Sadly, I can't see anything like this working.

tptacek 4 hours ago||
This is everyone's first pitch for why DANE would improve the WebPKI. But it doesn't make sense as risk management. It assumes that the most important TLD operators, .COM especially, are trustworthy. But we know .COM is not trustworthy, at all. And it gets worse when you leave the US. In much of the world, state organizations have explicit de jure control over all the popular top level domains.

This is a simple point but there's something subtler underneath it. Strict name constraints are an obvious seeming improvement to the WebPKI. I like them too. but eMudhra isn't just an Indian sovereign CA; it's an important global commercial vendor. On the other thread about this incident, 'agwa pointed out that an eMudhra subsidiary does a lot of the certificates for US universities.

You're still going to end up with the same concentrations of risk, because large CAs are going to want to issue in the most popular domains.

Don't get me wrong, anything that ratchets up the difficulty of running a CA (without unduly burdening LetsEncrypt) is a positive as far as I'm concerned. I'm just saying these are hard problems.

Ambroos 7 hours ago|
My oven (which has a camera and WiFi, don't ask, it's a great oven otherwise and doesn't exist without WiFi) received a software update this morning. I can't help but wonder if it's related.
M2Ys4U 5 hours ago||
Either that or it's running PHP
chrisjj 7 hours ago|||
You'll know this evening when it demands $10 to release your meal.
jesuswasjew 7 hours ago||
I see you love technology.
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