9 ms·

The Irrevocable SSL Certificates of Cloudflare

104 points by hurutparittya 2y ago

DerCommodore 2y ago
[flagged]
echlebek 2y ago
> In fact, the official stance of the SSL team at CloudFlare is that they won’t revoke unless the team has “determined the private key was compromised.” Sounds like you should email the private key to the Cloudflare security team as plain text
- watermelon0 2y ago
  It's not possible to get the private key for CloudFlare issued TLS certificates.
aaomidi 2y ago
Disclaimer: I’ve been an engineer on various CAs in the past. If you run into this issue, contact the CA directly and not Cloudflare. The CA is required to handle your request within 24 hours. If they do not, that is an incident for the CA.
- tgsovlerkhgsel 2y ago
  And Let's Encrypt actually provides an API for this: https://letsencrypt.org/docs/revoking/#using-a-different-authorized-account https://letsencrypt.org/docs/revoking/#using-a-different-aut... I don't think it makes a significant difference (I believe browsers don't implement revocation in any meaningful way), but the option exists.
  - aaomidi 2y ago
    Firefox does do revocation.
    - tgsovlerkhgsel 2y ago
      Huh, you're right - it also seems to be enabled by default. I tried with a clean profile and https://revoked.badssl.com/ https://revoked.badssl.com/ showed an error (Chrome loads the page).
      - crcastle 2y ago
        iOS Safari also shows an error and refuses to load the page.
  - vetrom 2y ago
    Lots of browsers avoid it for reasons, but isn't this the whole point of the OCSP(https://en.m.wikipedia.org/wiki/Online_Certificate_Status_Protocol https://en.m.wikipedia.org/wiki/Online_Certificate_Status_Pr...) and OCSP stapling?
    - tgsovlerkhgsel 2y ago
      Yes, protocols for this exist... but as you said, browsers tend to avoid them. Edit: Firefox seems to check revocation by default. https://revoked.badssl.com/ https://revoked.badssl.com/ if you want to test.
  - neurostimulant 2y ago
    This requires the certificat's private key, right? Can you download the key for letsencrypt certificates generated by cloudflare?
    - agwa 2y ago
      No, if you can complete challenges for every DNS name in the certificate then the API lets you revoke it.
    - tgsovlerkhgsel 2y ago
      No, as the section I linked explains, you can also prove that you own the domain and then revoke the cert without having the private key. It's meant exactly for cases where some other party has obtained a cert for your domain for whatever reason (change of ownership, compromise, ...)
- 8organicbits 2y ago
  This is a valid request, right? You'd claim that you've withdrawn permission from CF (not that the key was compromised). Looking at this RFC: https://datatracker.ietf.org/doc/html/rfc5280 https://datatracker.ietf.org/doc/html/rfc5280 And CF has no obligation to revoke the cert when it's no longer needed, nor to act as a free middleman between domain owner and CA.
  - aaomidi 2y ago
    CF does “technically” have that obligation under many subscriber agreements. Cloudflare could make this much easier by revoking the cert when the customer moves away from them. They probably should do this.
pyuser583 2y ago
I hate how necessary CF is.
- Titan2189 2y ago
  And by necessary you mean provide such a good service at a fair price that there's just no way around them, since everyone else is worse? If not, please explain how they are necessary? I run a large online service and am not using any of their products / services.
- intelVISA 2y ago
  That's mostly marketing, large scale packet filtering on modern hardware is very solved by this point.
mrbluecoat 2y ago
Another example of pay-to-play is their Keyless SSL for Enterprise only customers: https://developers.cloudflare.com/ssl/keyless-ssl/ https://developers.cloudflare.com/ssl/keyless-ssl/ I've wanted to use their infrastructure for years, but I just can't bring myself to relinquish private key control.
- webprofusion 2y ago
  Under what circumstances do you need to give Cloudflare your private keys? Certificates they acquire for their services (on your domain) use their own private keys.
  - zrm 2y ago
    Any private keys for your domain are your private keys. What makes them yours is who they allow to be impersonated.
arianvanp 2y ago
I ran into a similarly weird issue with CloudFlare. This post made me check my domain that I recently bought. I bought the domain passkey.exchange through Cloudflare on 12 April and I didn't set up ANYTHING on it. No DNS records. Nothing. I didn't touch it since Yet. Exactly at the purchase time. 3 certificates where added to the certificate transparency log: 2 from LetsEncrypt and one from Google. How? https://crt.sh/?q=passkey.exchange https://crt.sh/?q=passkey.exchange The only explanation that i have is that Cloudflare is doing some kind of integration testing after you buy a domain from them on Google Cloud and LetsEncrypt before giving you the domain. But that means they have some private key somewhere for 90 days. Across two different CAs.. Or I have really bad memory. Set up some Infrastructure on Google Cloud and then deprovisioned it again and removed all DNS records. Or I was hacked. It's really strange. Edit: digging further it must've been Cloudflare. The google cert has Not Before: Apr 12 22:01:51 2024 GMT My invoice is dated 22:49 UTC. One hour after the cert was issued?
- beeboobaa3 2y ago
  Yes, Cloudflare controls your DNS and they advertise setting up HTTPS for you. If they'd wait until you added a DNS record that's routed through them, which they are by default, then that'd be poor user experience. The timestamp difference is probably just Google backdating the certificate by an hour or 30 minutes to deal with clients whose clocks lag behind.
  - 8organicbits 2y ago
    What method do they use to get the certificate? I'd guess ACME DNS-01 challenge, but that means they are setting DNS records you didn't explicitly ask for. Getting a TLS certificate is pretty quick, I'd probably prefer to wait 10 seconds versus having unexpected DNS records. (edit: although I'm a DevOps engineer and I wrote my own subdomain registration service, so my preference will certainly not match others).
    - fastball 2y ago
      Many (most?) registrars add DNS you didn't explicitly ask for, like an A record on the root that says "this domain was purchased from Namecheap" or whatever. Do you know of a registrar that doesn't do that?
_lvbh 2y ago
I’ve been wanting to move off Cloudflare for a while for some self hosted things (I bought the domain on CF and had to wait a few months for it to be allowed to transfer). What registrar do people recommend? (other than porkbun which refuses to let me sign up with a VPN)
- cube2222 2y ago
  Recently did my research when moving around my own domain and settled on EasyDNS, as one that seemed most trustworthy (and with human support). Though I do use CloudFlare for DNS and pages - I use EasyDNS purely as a registrar.
- KingOfCoders 2y ago
  Because Germany, I use INWX as a domain registrar, they send me PDF invoices, which many others don't (used several other services, most where a pain with invoices and my accountant). I use Bunny CDN for DNS services.
  - lutoma 2y ago
    +1 for INWX. Reliable, reasonably cheap and domains is actually their core business rather than just something tacked on.
  - _cenw 2y ago
    I used to be on INWX (and still am for some .de domains), but they charge up to 2x for some gTLDs when compared to Cloudflare.
    - Beijinger 2y ago
      inwx is good for EU countries TLD. For generic COM/NET I use http://internet.bs http://internet.bs ,is pretty good. gandi was good too, but I was told that email is not free anymore with them. You can buy plain email service for a domain at Swisserland based https://www.infomaniak.com https://www.infomaniak.com for 18 Euros a year (IMAP, 5 Emails) Don't use Cloudflare https://expatcircle.com/cms/why-you-should-never-use-cloudflare-it-causes-problems-is-bad-for-seo-and-a-spyware-tool/ https://expatcircle.com/cms/why-you-should-never-use-cloudfl... If you do for domain price only, there are comparison sites. Just recently sombody posted one on YC. It may have been this one: https://tld-list.com/ https://tld-list.com/ Spaceship is owned by namecheap. Namecheap is supposed to be good too but I don't undertand why they would undercut their own prices. EDIT: Cheapest non-bait registrar seems to be cosmotown with 8.99 USD. They seem to prevent C&P on their about page and one of their "partners" a German company, does not even have a webpage. Turing Crypto GmbH I think I pass.
1f60c 2y ago
(2021)
darkr 2y ago
Revocation for random domains is kind of a moo point as chrome doesn’t do OCSP default, just CRLsets that are pushed out with browser releases, that probably won’t include your domain. Better instead just to have shorter TTL certs.
- HL33tibCe7 2y ago
  Yes, and note that Cloudflare supports 30-day certs, and in fact IIRC Cloudflare doesn’t issue 1-year certs at all any more
  - 5e92cb50239222b 2y ago
    I checked two domains registered through Cloudflare about a week ago and both have 1-year certificates issued by Sectigo, valid until May 2025. Never enabled DDoS protection or any other features besides editing DNS records.
deleted 2y ago
[deleted]
chaz6 2y ago
This paper seems relevant. It describes a new CT log with additional revocation transparency. https://eprint.iacr.org/2021/818.pdf https://eprint.iacr.org/2021/818.pdf For it to be useful, I imagine clients would need to query some central service every time it receives a certificate it has not seen before, which could potentially be a privacy concern. The only other alternative seems to be for clients to sync the entire revocation log, which would quickly grow in size.
- wongarsu 2y ago
  Clients could sync a bloom filter of revoked certificates. If the client encounters a certificate that matches the boom filter it would still need to check some online service to see whether the certificate was revokes or was a false positive. But for most unrevoked certificates the bloom filter would already tell you that it isn't revoked. Another benefit over a pure online service is that when you get a new bloom filter you check all known certificates against it to mark known certificates for rechecking (in case they got revoked since you last visited that page)
webprofusion 2y ago
It's not your certificate, it's theirs and they're letting you use it. The domain is yours, but you let them complete domain validation to get their certificate.
- deleted 2y ago
  [deleted]
bawolff 2y ago
Sounds 100% reasonable to me. You want free L7 ddos protection... well that comes with some costs.
- devsda 2y ago
  The costs of using cloudflare are well understood. We get something for free but lose some control over our site, domain and data. CF gains insight into potentially valuable data like client information, traffic, attack and request patterns. The costs and risks should be applicable as long as they enjoy the benefits but anything beyond a certain grace period doesn't sound reasonable. I can understand if CF didn't prioritize it enough to spend development resources on revoking a cert but I don't see an upside for CF to continue keeping the certificate after a customer exits. They are unnecessarily taking on extra (reputation) risk if the still valid cert is compromised and used by someone else.
  - bawolff 2y ago
    > I can understand if CF didn't prioritize it enough to spend development resources on revoking a cert but I don't see an upside for CF to continue keeping the certificate after a customer exits. We have no idea if cloudflare retained the cert. The blog post is just claiming that cloudflare did not revoke the certificate and instead is just letting it expire naturally. (That said, i wouldn't be surprised if they retained it) Potential upside for cloudflare is that if the client disabled ddos protection just temporarily to test something but intends to reenable it, this allows the reenable to happen instantly (assuming they kept the cert).
  - cchance 2y ago
    No one says that CF is retaining the cert lol, the article can't even show that they just know it hasn't been revoked, chances are CF just drops the certificate and deletes it when the user drops their usage, they don't go through the steps to also REVOKE the cert that used to be in use. Which would be nice but honestly most browsers don't even do revocation checks so... ya
tyilo 2y ago
(2021)
fancyfredbot 2y ago
I'm struggling to understand the mindset in which this seems "corrupt". The post isn't happy that cloudflare offers free DDOS protection, instead they are so upset that using the free level doesn't allow you to revoke their certificate for your website that they accuse cloudflare of being corrupt. That's grossly unfair to cloudflare. If you didn't want them to have a certificate for your website, don't give it to them!
- Drakim 2y ago
  I guess it could be argued that Cloudflare's free level is set up as a trap, where it's presented as free but if something goes wrong it costs money to fix it.
  - ffsm8 2y ago
    But that's not really what's happening here, is it? Theyre complaining that cloudflare doesn't have a way to revoke certificates after the user specifically asked cloudflare to create one for them - transparently, so they dont have to bother with the keys to this certificate. I'd wager the reason why this feature doesn't exist is because - by the time someone will want to revoke it, the private key for the certificate will have already been deleted, making revocation impossible. Honestly, this article has probably been written by someone that doesn't actually know how the certificates are created and revoked, forgot to remove a cname entry on their DNS and now wants to drum up controversy for clicks from ppl that probably shouldn't participate in the discussion either, as they're most likely not as informed as they think they're. And while I was a sysadmin around 10 yrs ago, which gives me a rudimentary understanding of the lifecycle of these certificates... I wouldn't call myself an expert either .
    - cchance 2y ago
      This honestly i never even thought about this, i mean sure Cloudflare COULD MITM them, but if the dns is already running through cloudflare, they could just reissue a new DNS challenged LetsEncrypt cert, they don't need your old cert to reissue a new one if they're the MITM and DNS hoster lol. Bitching about a cert not being revoked, is kinda silly since the guys running like 50% of the internet could easily just reissue a new letsencrypt cert to replace the one you "revoked" if they were mischeveous.
bell-cot 2y ago
Meh. While Cloudflare certainly isn't perfect...neither are their services provided by North Pole Elves. Doing Stuff for you is not free on their end. And what is the betrayed-by-a-CF-held-cert scenario that you are worried about here? Given their size, and that you are not exactly a major bank, I'd say that CF has 1000X more skin in this game than you do, if the your-domain-name cert that they hold was put to malicious use.
denton-scratch 2y ago
Have I got this right? Cloudflare serves an SSL certificate for each site that it MITMs, and they fail to revoke it when the site leaves Cloudflare. A site "leaving" Cloudflare means that the site's DNS no longer points to Cloudflare IP addresses. What's the problem? The departing site stops serving the Cloudflare certificate. Cloudflare is no longer the destination for visitors to the site, so it won't be serving the certificate either. The only way it could abuse the retained certificate would be if it controlled the site's DNS, so if $SITE_OWNER changes DNS provider, the retained certificate isn't a problem. What did I miss?
- vidarh 2y ago
  That you're now one significantly weakened link closer to a breach. In itself this isn't a problem, but every time a provider thinks this isn't a problem because there needs to be other weaknesses elsewhere too, the validity of that logic is weakened.
- lathiat 2y ago
  You missed this line: “This is from a CDN who has a level of access unmatched by their rivals. CloudFlare are becoming the defualt DNS for browsers and have a VPN service.” They’ve got a pretty large vector for intercepting real traffic from a substantial number of users.
  - bawolff 2y ago
    I mean, if that is the concern, maybe don't give them a cert in the first place.
    - 5e92cb50239222b 2y ago
      Lots of people use CloudFlare purely as a registar and DNS hoster because they sell domains at cost. Domains are quite expensive already for what they are. This is enough to trigger certificate issuance on your behalf. You don't have to use any add-on features. Maybe even just registering a domain is enough, I'm not sure. I certainly didn't "give them" any certificates, I don't have A/AAAA/CNAME records on several of my domains, and never enabled proxying traffic through the rest of them. The certs have been issued regardless. I don't see this as a conspiracy theory, though. They want to sell you the whole package and don't want to support freeloaders like me who are only there for the "cheap" domains. That's reasonable, if unfortunate.
hurutparittya 2y ago
I recently noticed that Cloudflare issued multiple, year-long certificates for one of my domains that has NOTHING to do with Cloudflare services. Trying to get them revoked has been an exercise in frustration and futility.
- aaomidi 2y ago
  Which CA is this? Contact their CPR endpoint and tell them you want it revoked. Don’t bother going through Cloudflare. If they don’t respond to you within 24 hours, let me know and we can start an incident against that CA.
  - hurutparittya 2y ago
    That was my first instinct as well! I reached out to Digicert at revoke@digicert.com. They responded almost immediately and directed me to Cloudflare's abuse report form, where I was met with a wall. Now I'm back to Digicert asking them to please revoke them. Note that this isn't an urgent security situation, as the domain in question isn't in use currently. It's more of an annoyance, since the certs are valid for 1 year. Certificates in question: https://crt.sh/?id=11447235791 https://crt.sh/?id=11447235791 https://crt.sh/?id=11447092451 https://crt.sh/?id=11447092451
    - aaomidi 2y ago
      This is actually very interesting. Please let me know what digicert says once you say your request again. If they push back on this I’ll escalate it with your permission.
      - aaomidi 2y ago
        I see the still haven’t revoked your cert. Has digicert started the revocation process?
        hurutparittya 2y ago

104 points by hurutparittya 2y ago

[flagged]

> In fact, the official stance of the SSL team at CloudFlare is that they won’t revoke unless the team has “determined the private key was compromised.” Sounds like you should email the private key to the Cloudflare security team as plain text

watermelon0 2y ago
It's not possible to get the private key for CloudFlare issued TLS certificates.

aaomidi 2y ago

Disclaimer: I’ve been an engineer on various CAs in the past. If you run into this issue, contact the CA directly and not Cloudflare. The CA is required to handle your request within 24 hours. If they do not, that is an incident for the CA.

tgsovlerkhgsel 2y ago
And Let's Encrypt actually provides an API for this: https://letsencrypt.org/docs/revoking/#using-a-different-authorized-account https://letsencrypt.org/docs/revoking/#using-a-different-aut... I don't think it makes a significant difference (I believe browsers don't implement revocation in any meaningful way), but the option exists.
- aaomidi 2y ago
  Firefox does do revocation.
  - tgsovlerkhgsel 2y ago
    Huh, you're right - it also seems to be enabled by default. I tried with a clean profile and https://revoked.badssl.com/ https://revoked.badssl.com/ showed an error (Chrome loads the page).
    - crcastle 2y ago
      iOS Safari also shows an error and refuses to load the page.
- vetrom 2y ago
  Lots of browsers avoid it for reasons, but isn't this the whole point of the OCSP(https://en.m.wikipedia.org/wiki/Online_Certificate_Status_Protocol https://en.m.wikipedia.org/wiki/Online_Certificate_Status_Pr...) and OCSP stapling?
  - tgsovlerkhgsel 2y ago
    Yes, protocols for this exist... but as you said, browsers tend to avoid them. Edit: Firefox seems to check revocation by default. https://revoked.badssl.com/ https://revoked.badssl.com/ if you want to test.
- neurostimulant 2y ago
  This requires the certificat's private key, right? Can you download the key for letsencrypt certificates generated by cloudflare?
  - agwa 2y ago
    No, if you can complete challenges for every DNS name in the certificate then the API lets you revoke it.
  - tgsovlerkhgsel 2y ago
    No, as the section I linked explains, you can also prove that you own the domain and then revoke the cert without having the private key. It's meant exactly for cases where some other party has obtained a cert for your domain for whatever reason (change of ownership, compromise, ...)
8organicbits 2y ago
This is a valid request, right? You'd claim that you've withdrawn permission from CF (not that the key was compromised). Looking at this RFC: https://datatracker.ietf.org/doc/html/rfc5280 https://datatracker.ietf.org/doc/html/rfc5280 And CF has no obligation to revoke the cert when it's no longer needed, nor to act as a free middleman between domain owner and CA.
- aaomidi 2y ago
  CF does “technically” have that obligation under many subscriber agreements. Cloudflare could make this much easier by revoking the cert when the customer moves away from them. They probably should do this.

pyuser583 2y ago

I hate how necessary CF is.

Titan2189 2y ago
And by necessary you mean provide such a good service at a fair price that there's just no way around them, since everyone else is worse? If not, please explain how they are necessary? I run a large online service and am not using any of their products / services.
intelVISA 2y ago
That's mostly marketing, large scale packet filtering on modern hardware is very solved by this point.

mrbluecoat 2y ago

Another example of pay-to-play is their Keyless SSL for Enterprise only customers: https://developers.cloudflare.com/ssl/keyless-ssl/ https://developers.cloudflare.com/ssl/keyless-ssl/ I've wanted to use their infrastructure for years, but I just can't bring myself to relinquish private key control.

webprofusion 2y ago
Under what circumstances do you need to give Cloudflare your private keys? Certificates they acquire for their services (on your domain) use their own private keys.
- zrm 2y ago
  Any private keys for your domain are your private keys. What makes them yours is who they allow to be impersonated.

arianvanp 2y ago

I ran into a similarly weird issue with CloudFlare. This post made me check my domain that I recently bought. I bought the domain passkey.exchange through Cloudflare on 12 April and I didn't set up ANYTHING on it. No DNS records. Nothing. I didn't touch it since Yet. Exactly at the purchase time. 3 certificates where added to the certificate transparency log: 2 from LetsEncrypt and one from Google. How? https://crt.sh/?q=passkey.exchange https://crt.sh/?q=passkey.exchange The only explanation that i have is that Cloudflare is doing some kind of integration testing after you buy a domain from them on Google Cloud and LetsEncrypt before giving you the domain. But that means they have some private key somewhere for 90 days. Across two different CAs.. Or I have really bad memory. Set up some Infrastructure on Google Cloud and then deprovisioned it again and removed all DNS records. Or I was hacked. It's really strange. Edit: digging further it must've been Cloudflare. The google cert has Not Before: Apr 12 22:01:51 2024 GMT My invoice is dated 22:49 UTC. One hour after the cert was issued?

beeboobaa3 2y ago
Yes, Cloudflare controls your DNS and they advertise setting up HTTPS for you. If they'd wait until you added a DNS record that's routed through them, which they are by default, then that'd be poor user experience. The timestamp difference is probably just Google backdating the certificate by an hour or 30 minutes to deal with clients whose clocks lag behind.
- 8organicbits 2y ago
  What method do they use to get the certificate? I'd guess ACME DNS-01 challenge, but that means they are setting DNS records you didn't explicitly ask for. Getting a TLS certificate is pretty quick, I'd probably prefer to wait 10 seconds versus having unexpected DNS records. (edit: although I'm a DevOps engineer and I wrote my own subdomain registration service, so my preference will certainly not match others).
  - fastball 2y ago
    Many (most?) registrars add DNS you didn't explicitly ask for, like an A record on the root that says "this domain was purchased from Namecheap" or whatever. Do you know of a registrar that doesn't do that?

_lvbh 2y ago

I’ve been wanting to move off Cloudflare for a while for some self hosted things (I bought the domain on CF and had to wait a few months for it to be allowed to transfer). What registrar do people recommend? (other than porkbun which refuses to let me sign up with a VPN)

cube2222 2y ago
Recently did my research when moving around my own domain and settled on EasyDNS, as one that seemed most trustworthy (and with human support). Though I do use CloudFlare for DNS and pages - I use EasyDNS purely as a registrar.
KingOfCoders 2y ago
Because Germany, I use INWX as a domain registrar, they send me PDF invoices, which many others don't (used several other services, most where a pain with invoices and my accountant). I use Bunny CDN for DNS services.
- lutoma 2y ago
  +1 for INWX. Reliable, reasonably cheap and domains is actually their core business rather than just something tacked on.
- _cenw 2y ago
  I used to be on INWX (and still am for some .de domains), but they charge up to 2x for some gTLDs when compared to Cloudflare.
  - Beijinger 2y ago
    inwx is good for EU countries TLD. For generic COM/NET I use http://internet.bs http://internet.bs ,is pretty good. gandi was good too, but I was told that email is not free anymore with them. You can buy plain email service for a domain at Swisserland based https://www.infomaniak.com https://www.infomaniak.com for 18 Euros a year (IMAP, 5 Emails) Don't use Cloudflare https://expatcircle.com/cms/why-you-should-never-use-cloudflare-it-causes-problems-is-bad-for-seo-and-a-spyware-tool/ https://expatcircle.com/cms/why-you-should-never-use-cloudfl... If you do for domain price only, there are comparison sites. Just recently sombody posted one on YC. It may have been this one: https://tld-list.com/ https://tld-list.com/ Spaceship is owned by namecheap. Namecheap is supposed to be good too but I don't undertand why they would undercut their own prices. EDIT: Cheapest non-bait registrar seems to be cosmotown with 8.99 USD. They seem to prevent C&P on their about page and one of their "partners" a German company, does not even have a webpage. Turing Crypto GmbH I think I pass.

1f60c 2y ago

(2021)

darkr 2y ago

Revocation for random domains is kind of a moo point as chrome doesn’t do OCSP default, just CRLsets that are pushed out with browser releases, that probably won’t include your domain. Better instead just to have shorter TTL certs.

HL33tibCe7 2y ago
Yes, and note that Cloudflare supports 30-day certs, and in fact IIRC Cloudflare doesn’t issue 1-year certs at all any more
- 5e92cb50239222b 2y ago
  I checked two domains registered through Cloudflare about a week ago and both have 1-year certificates issued by Sectigo, valid until May 2025. Never enabled DDoS protection or any other features besides editing DNS records.

deleted 2y ago

[deleted]

chaz6 2y ago

This paper seems relevant. It describes a new CT log with additional revocation transparency. https://eprint.iacr.org/2021/818.pdf https://eprint.iacr.org/2021/818.pdf For it to be useful, I imagine clients would need to query some central service every time it receives a certificate it has not seen before, which could potentially be a privacy concern. The only other alternative seems to be for clients to sync the entire revocation log, which would quickly grow in size.

wongarsu 2y ago
Clients could sync a bloom filter of revoked certificates. If the client encounters a certificate that matches the boom filter it would still need to check some online service to see whether the certificate was revokes or was a false positive. But for most unrevoked certificates the bloom filter would already tell you that it isn't revoked. Another benefit over a pure online service is that when you get a new bloom filter you check all known certificates against it to mark known certificates for rechecking (in case they got revoked since you last visited that page)

webprofusion 2y ago

It's not your certificate, it's theirs and they're letting you use it. The domain is yours, but you let them complete domain validation to get their certificate.

deleted 2y ago
[deleted]

bawolff 2y ago

Sounds 100% reasonable to me. You want free L7 ddos protection... well that comes with some costs.

devsda 2y ago
The costs of using cloudflare are well understood. We get something for free but lose some control over our site, domain and data. CF gains insight into potentially valuable data like client information, traffic, attack and request patterns. The costs and risks should be applicable as long as they enjoy the benefits but anything beyond a certain grace period doesn't sound reasonable. I can understand if CF didn't prioritize it enough to spend development resources on revoking a cert but I don't see an upside for CF to continue keeping the certificate after a customer exits. They are unnecessarily taking on extra (reputation) risk if the still valid cert is compromised and used by someone else.
- bawolff 2y ago
  > I can understand if CF didn't prioritize it enough to spend development resources on revoking a cert but I don't see an upside for CF to continue keeping the certificate after a customer exits. We have no idea if cloudflare retained the cert. The blog post is just claiming that cloudflare did not revoke the certificate and instead is just letting it expire naturally. (That said, i wouldn't be surprised if they retained it) Potential upside for cloudflare is that if the client disabled ddos protection just temporarily to test something but intends to reenable it, this allows the reenable to happen instantly (assuming they kept the cert).
- cchance 2y ago
  No one says that CF is retaining the cert lol, the article can't even show that they just know it hasn't been revoked, chances are CF just drops the certificate and deletes it when the user drops their usage, they don't go through the steps to also REVOKE the cert that used to be in use. Which would be nice but honestly most browsers don't even do revocation checks so... ya

tyilo 2y ago

(2021)

fancyfredbot 2y ago

I'm struggling to understand the mindset in which this seems "corrupt". The post isn't happy that cloudflare offers free DDOS protection, instead they are so upset that using the free level doesn't allow you to revoke their certificate for your website that they accuse cloudflare of being corrupt. That's grossly unfair to cloudflare. If you didn't want them to have a certificate for your website, don't give it to them!

Drakim 2y ago
I guess it could be argued that Cloudflare's free level is set up as a trap, where it's presented as free but if something goes wrong it costs money to fix it.
- ffsm8 2y ago
  But that's not really what's happening here, is it? Theyre complaining that cloudflare doesn't have a way to revoke certificates after the user specifically asked cloudflare to create one for them - transparently, so they dont have to bother with the keys to this certificate. I'd wager the reason why this feature doesn't exist is because - by the time someone will want to revoke it, the private key for the certificate will have already been deleted, making revocation impossible. Honestly, this article has probably been written by someone that doesn't actually know how the certificates are created and revoked, forgot to remove a cname entry on their DNS and now wants to drum up controversy for clicks from ppl that probably shouldn't participate in the discussion either, as they're most likely not as informed as they think they're. And while I was a sysadmin around 10 yrs ago, which gives me a rudimentary understanding of the lifecycle of these certificates... I wouldn't call myself an expert either .
  - cchance 2y ago
    This honestly i never even thought about this, i mean sure Cloudflare COULD MITM them, but if the dns is already running through cloudflare, they could just reissue a new DNS challenged LetsEncrypt cert, they don't need your old cert to reissue a new one if they're the MITM and DNS hoster lol. Bitching about a cert not being revoked, is kinda silly since the guys running like 50% of the internet could easily just reissue a new letsencrypt cert to replace the one you "revoked" if they were mischeveous.

bell-cot 2y ago

Meh. While Cloudflare certainly isn't perfect...neither are their services provided by North Pole Elves. Doing Stuff for you is not free on their end. And what is the betrayed-by-a-CF-held-cert scenario that you are worried about here? Given their size, and that you are not exactly a major bank, I'd say that CF has 1000X more skin in this game than you do, if the your-domain-name cert that they hold was put to malicious use.

denton-scratch 2y ago

Have I got this right? Cloudflare serves an SSL certificate for each site that it MITMs, and they fail to revoke it when the site leaves Cloudflare. A site "leaving" Cloudflare means that the site's DNS no longer points to Cloudflare IP addresses. What's the problem? The departing site stops serving the Cloudflare certificate. Cloudflare is no longer the destination for visitors to the site, so it won't be serving the certificate either. The only way it could abuse the retained certificate would be if it controlled the site's DNS, so if $SITE_OWNER changes DNS provider, the retained certificate isn't a problem. What did I miss?

vidarh 2y ago
That you're now one significantly weakened link closer to a breach. In itself this isn't a problem, but every time a provider thinks this isn't a problem because there needs to be other weaknesses elsewhere too, the validity of that logic is weakened.
lathiat 2y ago
You missed this line: “This is from a CDN who has a level of access unmatched by their rivals. CloudFlare are becoming the defualt DNS for browsers and have a VPN service.” They’ve got a pretty large vector for intercepting real traffic from a substantial number of users.
- bawolff 2y ago
  I mean, if that is the concern, maybe don't give them a cert in the first place.
  - 5e92cb50239222b 2y ago
    Lots of people use CloudFlare purely as a registar and DNS hoster because they sell domains at cost. Domains are quite expensive already for what they are. This is enough to trigger certificate issuance on your behalf. You don't have to use any add-on features. Maybe even just registering a domain is enough, I'm not sure. I certainly didn't "give them" any certificates, I don't have A/AAAA/CNAME records on several of my domains, and never enabled proxying traffic through the rest of them. The certs have been issued regardless. I don't see this as a conspiracy theory, though. They want to sell you the whole package and don't want to support freeloaders like me who are only there for the "cheap" domains. That's reasonable, if unfortunate.

hurutparittya 2y ago

I recently noticed that Cloudflare issued multiple, year-long certificates for one of my domains that has NOTHING to do with Cloudflare services. Trying to get them revoked has been an exercise in frustration and futility.

aaomidi 2y ago
Which CA is this? Contact their CPR endpoint and tell them you want it revoked. Don’t bother going through Cloudflare. If they don’t respond to you within 24 hours, let me know and we can start an incident against that CA.
- hurutparittya 2y ago
  That was my first instinct as well! I reached out to Digicert at revoke@digicert.com. They responded almost immediately and directed me to Cloudflare's abuse report form, where I was met with a wall. Now I'm back to Digicert asking them to please revoke them. Note that this isn't an urgent security situation, as the domain in question isn't in use currently. It's more of an annoyance, since the certs are valid for 1 year. Certificates in question: https://crt.sh/?id=11447235791 https://crt.sh/?id=11447235791 https://crt.sh/?id=11447092451 https://crt.sh/?id=11447092451
  - aaomidi 2y ago
    This is actually very interesting. Please let me know what digicert says once you say your request again. If they push back on this I’ll escalate it with your permission.
    - aaomidi 2y ago
      I see the still haven’t revoked your cert. Has digicert started the revocation process?
      - hurutparittya 2y ago