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StartSSL domain validation vulnerability

oalmanna.blogspot.com

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Re: StartSSL domain validation vulnerability

#21

Post by dopamean »

pfg wrote: post #4

> This method is rarely used, instead for the domain validation most certificate authorities ask the domain owner to place a certain file in their websites. This statement strikes me as odd. Email-based validation is the most common validation method used by most CAs for DV certificates. The only exceptions that come to mind are WoSign and Let's Encrypt. The vulnerability is pretty bad, though. Good catch.

I work for a hosting provider that acts as a reseller of certs and we use the DV file option the author speaks of. It's easy for us because we can automate the entire process for the customer.

Whenever I've bought a cert for myself I've used the same process. I never thought email verification seemed like a great idea.

Re: StartSSL domain validation vulnerability

#23

Post by Animats »

keketi wrote: post #5

A vulnerability of this level is inexcusable. StartSSL ought to be removed from all major browsers.

Right now, StartSSL needs to do a quick search on their database to see which certs had email sent to a domain other than the one for which the cert applies. All such certs should be revoked immediately, and the owners of the domains involved notified of the breach.

Also, did they check properly for TLD and subdomain issues? If I have "me.blogspot.com", can I get a cert for "blogspot.com"? (What's a TLD today? It's complicated. See "https://publicsuffix.org/")

Re: StartSSL domain validation vulnerability

#24

Post by pfg »

dopamean wrote: post #21
pfg wrote: post #4

> This method is rarely used, instead for the domain validation most certificate authorities ask the domain owner to place a certain file in their websites. This statement strikes me as odd. Email-based validation is the most common validation method used by most CAs for DV certificates. The only exceptions that come to mind are WoSign and Let's Encrypt. The vulnerability is pretty bad, though. Good catch.

I work for a hosting provider that acts as a reseller of certs and we use the DV file option the author speaks of. It's easy for us because we can automate the entire process for the customer. Whenever I've bought a cert for myself I've used the same process. I never thought email verification seemed like a great idea.

It's certainly easier for automation. I think the security implications are mostly the same - you're vulnerable to DNS spoofing and BGP hijacking either way. With email validation, a misconfigured or breached email server is enough to get a certificate, while with http validation, it's your web server or web app that could be vulnerable.

Re: StartSSL domain validation vulnerability

#25

Post by Strom »

keketi wrote: post #5

A vulnerability of this level is inexcusable. StartSSL ought to be removed from all major browsers.

You would soon be left without any CAs. [1] People are pretty stupid when it comes to security, and this includes people working for CAs. There have been cases where the CA private key is publicly accessible to the internet without any password. [2]

--

[1] Yes, plenty of smart people have been advocating moving away from the current CA system. It's fundamentally broken.

[2] A great talk by moxie, filled with horror examples of CAs. The private key example is at 19:20. https://www.youtube.com/watch?v=Z7Wl2FW2TcA

Re: StartSSL domain validation vulnerability

#26

Post by gist »

Karunamon wrote: post #9

Now that Let's Encrypt is a thing, there's no reason to do business with these greedy losers. That's not just an off the cuff insult either - I find very few charitable words to describe a company that charges $25 to rekey a certificate for reasons outside the user's control, i.e. heartbleed. More to the point, in my arrogant opinion, now that a good , free alternative exists, users in the know should pressure the br…

> there's no reason to do business with these greedy losers

What makes them greedy? That they are charging for what they do? (Serious question I am curious why you label them "greedy" and further "losers").

Re: StartSSL domain validation vulnerability

#27

Post by pfg »

Strom wrote: post #25
keketi wrote: post #5

A vulnerability of this level is inexcusable. StartSSL ought to be removed from all major browsers.

You would soon be left without any CAs. [1] People are pretty stupid when it comes to security, and this includes people working for CAs. There have been cases where the CA private key is publicly accessible to the internet without any password. [2] -- [1] Yes, plenty of smart people have been advocating moving away from the current CA system. It's fundamentally broken. [2] A great talk by moxie, filled with horror e…

Certificate Transparency with mandatory SCT delivery (as with EV certificates) will largely solve¹ the issue of fraudulent or compromised CAs.

¹ As long as you're monitoring CT log servers for anything involving domains you own.

Re: StartSSL domain validation vulnerability

#28

Post by mynameisvlad »

gist wrote: post #26
Karunamon wrote: post #9

Now that Let's Encrypt is a thing, there's no reason to do business with these greedy losers. That's not just an off the cuff insult either - I find very few charitable words to describe a company that charges $25 to rekey a certificate for reasons outside the user's control, i.e. heartbleed. More to the point, in my arrogant opinion, now that a good , free alternative exists, users in the know should pressure the br…

> there's no reason to do business with these greedy losers What makes them greedy? That they are charging for what they do? (Serious question I am curious why you label them "greedy" and further "losers").

https://www.startssl.com/Support?v=43

They're the CA that wanted to charge $25 to revoke free certificates that were potentially compromised due to Heartbleed. Yes, it wasn't their fault, so they wouldn't be legally responsible for it, but they're acting in bad form by not offering those revocations for free for such a major issue.

Re: StartSSL domain validation vulnerability

#30

Post by kevincox »

Animats wrote: post #23
keketi wrote: post #5

A vulnerability of this level is inexcusable. StartSSL ought to be removed from all major browsers.

Right now, StartSSL needs to do a quick search on their database to see which certs had email sent to a domain other than the one for which the cert applies. All such certs should be revoked immediately, and the owners of the domains involved notified of the breach. Also, did they check properly for TLD and subdomain issues? If I have "me.blogspot.com", can I get a cert for "blogspot.com"? (What's a TLD today? It's c…

StartSSL only allows validation for top level domains. So you can't get a cert for me.blogspot.com unless you own blogspot.com.
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