I guess they can check logs and find how many times this has been abused already? Can we trust them to release full transparent report?
>We will provide a preliminary report on or before 2025-04-21.
Ssl.com: DCV bypass and issue fake certificates for any MX hostname
11–20 of 66 posts
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#12I guess they can check logs and find how many times this has been abused already? Can we trust them to release full transparent report?
They will need to most likely do a full mass revocation at this point.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#13Wow... this is the most serious TLS issue I've seen since following these things.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#14So I guess you couldn't get certificates for any random (MX) domain, only for those where you can obtain an inbox / user account. Still really bad, especially for things like gmail.com, but also larger enterprises. Intense.
It is unlikely that SSL.com would issue a certificate for any major mail host; it would be malpractice for them not to have some kind of exclusion list. Issuing a Google certificate is a good way to get your whole CA killed.
Sure, gmail.com might be excluded, but its still a massive hole for a few reasons.
This would affect ANY email provider who offers public email addresses. While I agree gmail.com is probably excluded (and maybe this doesn't bypass CAA -- maybe it does) there's a whole additional surface of anyone who has an email at any big enterprise getting a certificate for their domain.
Even if I work at google.com, therefore have a google.com email, I should absolutely not be able to get a certificate for google.com just by getting an email at that company.
I doubt it's even /that hard/ to buy an email account at a big company like that in the underground world, it seems like they are valuable generally and any company with 200k employees is going to have some leaks. This massively increases the attack surface of a simple leaked email account (which might otherwise have very little or no access).
Crazy crazy oversight that has huge implications and is so easy to carry out that I would not be surprised if this was actually exploited by bad actors.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#15So I guess you couldn't get certificates for any random (MX) domain, only for those where you can obtain an inbox / user account. Still really bad, especially for things like gmail.com, but also larger enterprises. Intense.
Even then, use of a DNS CAA record should mitigate this, right?
Maybe?
I wouldn't assume that the bug doesn't bypass CAA checking.
Very important question to answer.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#16> We will provide a preliminary report on or before 2025-04-21.
Bunch of engineers just got their easter weekend ruined. Sucks.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#17I guess they can check logs and find how many times this has been abused already? Can we trust them to release full transparent report?
I would expect them to be able to report on certificates issued based on this validation method. That's a basic CA capability and other CA incidents often include these kinds of reports.
Depending on what was logged during the validation, it might be tricky to determine if it was abuse or not. If the DNS content wasn't logged, they could pull a live record and report if the current record would support validation or not.
My guess is that use of this method should be low... If you're updating DNS to add a TXT record, you might be more likely to add a direct verification value rather than an email. But that's speculative; I'm not a CA, I've just been a customer of several... IIRC, I've validated domain control by controlling postmaster@ (or the whois address when that was public) or adding direct TXT verification records or ACME http validations.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#18So I guess you couldn't get certificates for any random (MX) domain, only for those where you can obtain an inbox / user account. Still really bad, especially for things like gmail.com, but also larger enterprises. Intense.
It is unlikely that SSL.com would issue a certificate for any major mail host; it would be malpractice for them not to have some kind of exclusion list. Issuing a Google certificate is a good way to get your whole CA killed.
> Issuing a Google certificate is a good way to get your whole CA killed.
Surely what happened here is a good way to get your CA killed? The linked bug seems pretty bad.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#19Earlier quoted context omitted.
It is unlikely that SSL.com would issue a certificate for any major mail host; it would be malpractice for them not to have some kind of exclusion list. Issuing a Google certificate is a good way to get your whole CA killed.
> Issuing a Google certificate is a good way to get your whole CA killed. Surely what happened here is a good way to get your CA killed? The linked bug seems pretty bad.
Less clear on that. Bugs happen. I'm not an expert on browser root policies.
Re: Ssl.com: DCV bypass and issue fake certificates for any MX hostname
#20Earlier quoted context omitted.
> Issuing a Google certificate is a good way to get your whole CA killed. Surely what happened here is a good way to get your CA killed? The linked bug seems pretty bad.
Less clear on that. Bugs happen. I'm not an expert on browser root policies.
From what I understand one of the factors is how often things like this happen, and how well they handle it when it does.