Chinese CA WoSign faces revocation after possibly issuing fake certificates • Hacker News Board

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#21

Post by Buetol » Tue, Aug 30, 2016, 2:29 PM UTC

michaelt wrote: post #12

Buetol wrote: post #8

Earlier quoted context omitted.

+1 revoking a CA using the issuance date seems like the right solution

It would certainly be better than nothing, yes. But prior to March 2015, CAs could issue certs valid for up to 5 years. So even if browsers stopped accepting WoSign certs with an issuance date after today, WoSign could still issue certs "issued March 2015 valid until to March 2020" and browsers would accept them.

Maybe the best would be to build a whitelist of WoSign certs then, scrap it from the publicly available websites and allow people to submit their own. Then some kind of bloom filter could do the trick I guess.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#22

Post by LoSboccacc » Tue, Aug 30, 2016, 2:30 PM UTC

Sir_Cmpwn wrote: post #6

verroq wrote: post #4

Earlier quoted context omitted.

[deleted]

You can only accept certs issued before a given date, though.

but you have to code that in every browser and hope people will be able to patch up. a revocation list from parent certificate company nuking the ca is the intended way to deal with trust breach, it should be supported everywhere, and doesn't require a full redeployment of browsers (And sometime entire OSes!) across the world.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#23

Post by buraktamturk » Tue, Aug 30, 2016, 2:42 PM UTC

Buetol wrote: post #8

michaelt wrote: post #5

Traditionally it's difficult for browser vendors to revoke a root CA as they want to grandfather in old certificates, so existing sites don't have the rug pulled out from under their feet when their only crime is using a crap CA. Partial solutions include blocking the CA's certs based on the issuance date or insisting they hand over a list of the certs they've issued - but if the CA is going down in flames anyway, th…

+1 revoking a CA using the issuance date seems like the right solution

The same company also cheats on issuance date to support SHA1 signatures. I heard it on HN on another topic.

Edit: source https://groups.google.com/forum/#!topic/mozilla.dev.security...

Incident 2 ----------

In July 2016, it became clear that there was some problems with the StartEncrypt automatic issuance service recently deployed by the CA StartCom. As well as other problems it had, which are outside the scope of this discussion, changing a simple API parameter in the POST request on the submission page changed the root certificate to which the resulting certificate chained up. The value "2" made a certificate signed by "StartCom Class 1 DV Server CA", "1" selected "WoSign CA Free SSL Certificate G2" and "0" selected "CA 沃通根证书", another root certificate owned by WoSign and trusted by Firefox.

Using the value "1" led to a certificate which had a notBefore date (usage start date) of 20th December 2015, and which was signed using the SHA-1 checksum algorithm.

* The issuance of certificates using SHA-1 has been banned by the Baseline Requirements since January 1st, 2016. Browsers, including Firefox, planned to enforce this[2] by not trusting certs with a notBefore date after that date, but in the case of Firefox the fix had to be backed out due to web compatibility issues. However, we are considering how/when to reintroduce it, and CAs presumably know this.

* The issuance of backdated certificates is not forbidden, but is listed in Mozilla's list of Problematic Practices[3]. It says "Minor tweaking for technical compatibility reasons is accepted, but backdating certificates in order to avoid some deadline or code-enforced restriction is not."

* WoSign deny that their code backdated the certificates in order to avoid browser-based restrictions - they say "this date is the day we stop to use this code"[4]. If that is true, it is not clear to us how StartCom came to deploy WoSign code that WoSign itself had abandoned.

* It seems clear from publicly available information that StartCom's issuance systems are linked to WoSign's issuance systems in some way. Nevertheless, it should not have been possible for an application for a cert from StartCom to produce a cert signed by WoSign.

* This misissuance incident was not reported to Mozilla by WoSign as it should have been.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#24

Post by guelo » Tue, Aug 30, 2016, 2:42 PM UTC

hannob wrote: post #16

guelo wrote: post #15

I just went to delete these roots from my Windows system but it's not listed. It was in Firefox's list but not in Window's. Anyone know why?

They're cross-signed by startcom.

I'm not familiar with this. Does it mean that if you trust StartCom you have to trust WoSign?

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#25

Post by throwaway7767 » Tue, Aug 30, 2016, 2:42 PM UTC

mtgx wrote: post #2

> Possible fake cert for Github https://crt.sh/?id=29647048 https://crt.sh/?id=29805567 > Possible fake cert for Alibaba, the largest commercial site in China https://crt.sh/?id=29884704 > Possible fake cert for Microsoft https://crt.sh/?id=29805555 Yikes. If all of that is true, surely Google will permanently ban WoSign from Chrome? And I would hope Mozilla and Microsoft, too, but Google is usually the one to "play…

> Yikes. If all of that is true, surely Google will permanently ban WoSign from Chrome? And I would hope Mozilla and Microsoft, too, but Google is usually the one to "play tough" with rogue CAs (and I hope they will strive to develop and maintain that reputation).

This will most likely happen, because a) the CA is not a western CA and b) it was due to incompetence.

If they had been competent but intentionally and willfully broken the trust of the CA system, assuming they had enough money, they would keep their CA cert. Case in point: TrustWave still has their CA certificate after intentionally selling sub-CAs for the purpose of MITM! But don't worry, they promised they'll never to it again, honest.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#26

Post by detaro » Tue, Aug 30, 2016, 2:46 PM UTC

guelo wrote: post #24

hannob wrote: post #16

Earlier quoted context omitted.

They're cross-signed by startcom.

I'm not familiar with this. Does it mean that if you trust StartCom you have to trust WoSign?

No, you can explicitly install the WoSign certificate into the "Untrusted Certificates" chain.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#27

Post by the_mitsuhiko » Tue, Aug 30, 2016, 2:50 PM UTC

cm2187 wrote: post #14

michaelt wrote: post #5

Traditionally it's difficult for browser vendors to revoke a root CA as they want to grandfather in old certificates, so existing sites don't have the rug pulled out from under their feet when their only crime is using a crap CA. Partial solutions include blocking the CA's certs based on the issuance date or insisting they hand over a list of the certs they've issued - but if the CA is going down in flames anyway, th…

That's exactly the internet equivalent of too big to fail banks. And like for banks it is unacceptable. The internet needs its Lehman moment to become resilient again. We should let a Comodo fail.

So what is the solution to big banks and big CAs? We are just in the process of collectively creating the biggest CA the world ha sver seen.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#28

Post by privong » Tue, Aug 30, 2016, 2:55 PM UTC

LoSboccacc wrote: post #20

michaelt wrote: post #5

Traditionally it's difficult for browser vendors to revoke a root CA as they want to grandfather in old certificates, so existing sites don't have the rug pulled out from under their feet when their only crime is using a crap CA. Partial solutions include blocking the CA's certs based on the issuance date or insisting they hand over a list of the certs they've issued - but if the CA is going down in flames anyway, th…

> their only crime is using a crap CA thing is the whole castle is built upon trust. if you don't punish crap CA and ppl who don't do research first, things will deteriorate rapidly.

> if you don't punish ... ppl who don't do research first, things will deteriorate rapidly.

Is there a way customers would have or could have known beforehand that this CA was fishy? I agree that the CA should be punished/ostracized, but it isn't obvious to me that most of its customers would have known they were a fishy CA.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#29

Post by mrb » Tue, Aug 30, 2016, 2:57 PM UTC

the_mitsuhiko wrote: post #27

cm2187 wrote: post #14

Earlier quoted context omitted.

That's exactly the internet equivalent of too big to fail banks. And like for banks it is unacceptable. The internet needs its Lehman moment to become resilient again. We should let a Comodo fail.

So what is the solution to big banks and big CAs? We are just in the process of collectively creating the biggest CA the world ha sver seen.

With CT we could in theory revoke big CAs without impacting sites currently using them.

Re: Chinese CA WoSign faces revocation after possibly issuing fake certificates

#30

Post by wildmusings » Tue, Aug 30, 2016, 2:57 PM UTC

Is there an easy way for me to revoke trust from all Chinese CAs? Anyone in China is ultimately subject to being forced to do the dirty work of the Chinese Communist Party. Why are browser and OS vendors even trusting them in the first place?