Cert Authorities Check for DNSSEC from Today
grepular.com63 points by zdw a day ago
63 points by zdw a day ago
Wouldn’t it make more sense to design a new, simple API and glue for doing secure DNS lookups just for certificate issuance? It could look more like dnscurve or even like HTTPS: have a new resource, say NSS, in parallel with NS. To securely traverse to a subdomain, you would query the parent for NSS and, if the record is present, you would learn an IP address and a public key hash or certificate hash that you can query via HTTPS to read the next domain. And this whole spec would say that normal HTTPS clients and OS resolvers SHOULD NOT use it. So if you mess it up, your site doesn’t go offline.
(HTTPS really needs a way to make a URL where the URL itself encodes the keying information.)
Even if you hate dnssec (and there are many legit criticisms to make) i think it does make sense for CA's to validate it if its there. Its low effort on the CA side, and there isn't really very much downside if its already active.
DNSSEC is one of very few topics where voices I respect on security seem completely opposed (WebPKI depends on DNS vs. DNS security does not matter). Is there any literature that demonstrates deep understanding of both arguments? Why are they (DNSSEC + WebPKI) never considered complimentary?
You'll have to judge for yourself whether this demonstrates deep understanding of both arguments, but I did try to be evenhanded in these posts:
https://educatedguesswork.org/posts/dns-security-dnssec/ https://educatedguesswork.org/posts/dns-security-dane/
From my perspective, the challenge with DNSSEC is that it just doesn't have a very good cost/benefit ratio. Once the WebPKI exists, "critical path" use of DNSSEC only offers modest value. Now, obviously, this article is about requiring CAs to check DNSSEC, which is out of the critical path and of some value, but it's not clear to me it's of enough value to get people to actually roll out DNSSEC.
> Why are they (DNSSEC + WebPKI) never considered complimentary?
WebPKI works without DNSSEC, whereas DANE (a more secure WebPKI replacement) depends on a robust DNSSEC deployment.
Bad arguments and FUD when it was being rolled out. Sysadmins also don't want to touch working infra code, you can see that with AWS lagging on IPv6.
Who's the most reputable cryptographer you can think of who publicly supports DNSSEC? We'd like to interview them on SCW.
You are going to complain that the key sizes are too small despite the guidelines being updated a long time ago. Then you will argue adoption of larger keys sizes is to low. Then you will argue that we should just not sign domain name authority delegation records at all (i.e. DNSSEC) and that we should abandon shoring up authenticated DNS because there is no adoption.
You have any cryptographers that are satisfied with unauthenticated name server checks?
I enabled DNSSEC a couple of years ago on my self hosted powerdns setup. I sign the zone locally, than build docker containers via SSH on the target nodes.
I made a mistake once and signed with wrong keys which then broke DANE. It‘s good to validate your DNSSEC (and DANE, CAA etc.) setup through external monitoring.
Is there non-ICANN DNSSEC
Everyone knows "WebPKI", e.g., self-appointed "cert authorities", generally relies on DNS
With an added DNSSEC step, perhaps this is now limited to ICANN DNS only
Self-appointed "cert authorities" checking with self-appointed domainname "authority". A closed system
You can add multiple trust anchors to DNSSEC resolvers. Before the "." zone was signed, adding zone-specific anchors was the only way to get DNSSEC working.
In case the post is fuzzy: what's changed is that as of March 2026, CAs are required to validate DNSSEC if it's enabled when doing DCV or CAA. Previously, it was technically the case that a CA could ignore DNSSEC if you had it set up on your domains, though LetsEncrypt has (as I understand it) been checking DNSSEC pretty much this whole time.
If you own and host your own domain, it's probably very easy to have your DNS provider enable DNSSEC for you, maybe just a button click. They'd sure like you to do that, because DNSSEC is itself quite complicated, and once you press that button it's much less likely that you're going to leave your provider. DNSSEC mistakes take your entire domain off the Internet, as if it had never existed.
There's a research project, started at KU Leuven, that attempts an unbiased "top N" list of most popular domains; it's called the Tranco List. For the last year or so, I've monitored the top 1000 domains on the Tranco list to see which have DNSSEC enabled. You can see that here:
There's 2 tl;dr's to this:
First, DNSSEC penetration in the top 1000 is single digits % (dropping sharply, down to 2%, as you scope down to the top 100).
Second, in a year of monitoring and recording every change in DNSSEC state on every domain in this list, I've seen just three Tranco Top 1000 domains change their DNSSEC state, and one of those changes was Canva disabling DNSSEC. (I think, as of a few weeks ago, they've re-enabled it again). Think about that: 1000 very popular domains, and just 0.3% of them thought even a second about DNSSEC.
DNSSEC is moribund.
That’s a fun list, the only hits in the top 100 are actually Cloudflare, for whom automatic DNSSEC is a feature, and would be a bad look not to dogfood it.
(I did a lot of the work of shipping that product in a past life. We had to fight the protocol and sometimes the implementers to beat it into something deployable. I am proud of that work from a technical point of view, but I agree DNSSEC adds little systemic value and haven’t thought about it since moving on from that project almost 10 years ago. It doesn’t look like DNSSEC itself has changed since, either.)
Then a few government sites, which have mandated it. The first hit after those is around #150.
What's your replacement if DNSSEC is moribund?
It seems to me like it actually solves a problem, what is the solution to "I want/need to be able to trust the DNS answer" without DNSSEC?
Largely, DNS integrity has been addressed by making it harder to spoof dns responses without visibility.
Resolvers have put in the effort to use most of the range of source ports and all of the range of request ids, as well as mixed caps, so predicting queries is difficult and blind spoofing requires an unreasonable number of packets.
Additionally, commercial DNS services tend to be well connected anycast. This means most queries can be served with a very low round trip time; reducing the spoofing window. Additionally, there's less opportunity to observe requests as they traverse fewer networks and less distance.
Generally, traffic has moved to certificate authenticated protocols. CAs are required to verify domain control from multiple locations, so an attacker asserting domain control would need to do so for the victim as well as multiple other locations in order to get a certificate issued.
Further; if we assume you plan to assert domain control by taking over or MITMing the IP of a DNS server, it seems likely you could do the same for the IP of an application server. DNSSEC doesn't help very much in that case. (DNSSEC with DANE could help in that case, but to a first approximation, nothing supports that, and there doesn't appear to be any movement towards it)
Port randomization helps against blind spoofing, but once an attacker is on-path or owns a resolver, it stops mattering.
If an attacker owns a resolver DNSSEC stops mattering too; from the resolver to the stub-resolver, the protocol collapses down to a single "yes we did DNSSEC" bit in the header.
The bigger thing here is DoH, which has very real penetration, and works for zones that don't do anything to opt-in. That's what a good design looks like: it just works without uninvolved people having to do extra stuff.
I think DNSSEC supporters, what few of them are left, are really deep into cope about what transport security is doing to the the rationale for DNSSEC deployment. There's nothing about DoH that makes it complicated to speak it to an authority server. The only reason I can see that we're not going to get that is that multi-perspective kills the value proposition of even doing that much.
It seems pretty clear to me that the industry, and particularly the slice of the industry that operates large, important sites and staffs big security teams, doesn't believe this is a meaningful problem at all.
I agree with them.
Big sites don't have the same concerns as individual end users, in this case specifically about centralized servers surveilling DNS queries.
DNSSEC zone signing lets one resolve records without having to directly go through trusted (ie centralizing) nameservers. (If you run your own recursive resolver this just changes the set of trusted servers to the zones' servers).
I've made this argument in the context of your poo-pooing DNSSEC before, and I don't expect you to be receptive to it this time. Rather I just really wish I could get around to writing code to demonstrate what I mean.
Would this article not be evidence the part of the industry that makes up the CA/B Forum (i.e. CAs and Browsers) disagree?
The fact that it's 2026 and the CAs are only now getting around to requiring any CA to take DNSSEC, which has in its current form been operational for well over a decade, makes you take DNSSEC more seriously?
Why dodge the question? Clearly they care today, and I live in today.
If we're doing to defer to industry, does only the opinion of website operators matter, or do browsers and CAs matter too? Browsers and CAs tend to be pretty important and staff big security teams too.
Are they requiring DNSSEC in order to acquire the certificate? That would be a better indicator to me that it's not security theater=security
Barely 5% of the internet have DNSSEC signed zones and a big chunk of that are handled by CDN's that do the signing automagically for the domain owner as they also host SOA DNS. Mandating DNSSEC would require years of planning and warning those that have not yet set it up and in my opinion DNSSEC tooling should become a better first class citizen in all of the authoritative DNS daemons. as in there should be so many levels of error handling and validation that it would be next to impossible for anyone to break their zones.
So do we wait for all the stragglers? Wait for the top 500 or top 2500 to make it mandatory? Who takes financial responsibility for those that fell through the cracks?
No CA requires DNSSEC. Obviously they can't: almost nothing is signed. The only change "today" is that technically CAs are now required to honor DNSSEC, where they weren't before.
I think the fact they don't require it shows it's moribund. If cert providers (or google with their big stick of chrome) specified it is required to have DNSSEC to get a certificate, everyone would jump in line and set it up because there'd be no other choice.