8 ms·

Sorry for asking a potentially dumb question : but is it possible for me to set up a domain name thecitibank.com and ask letsencrypt to issue me a certificate ?

Sorry for asking a potentially dumb question : but is it possible for me to set up a domain name thecitibank.com and ask letsencrypt to issue me a certificate ? I can then create a login page to steal IPINs. Isn't that why we have humans in the loop for issuing certificates ?

superuser2 11y ago
We don't have humans in the loop for issuing certificate; this can and has been exploited for fun and profit, with fun attacks like getting a cert for "citibank.com\0.mydomain.com" which used to trick the C strcmp in most browser certificate checking routines. Moxie has an entertaining talk: https://www.youtube.com/watch?v=MFol6IMbZ7Y https://www.youtube.com/watch?v=MFol6IMbZ7Y Your problem would be getting people to "thecitibank.com." Chrome, Firefox, and GMail would all eventually figure out it was a phishing site and warn users about clicking through to it.
cbg0 11y ago
Actually it's automated in most places, simply requiring you to confirm a request via an e-mail address associated with the domain you're getting an SSL for (typically admin@ hostmaster@ webmaster@, though it varies between certificate providers).
- duskwuff 11y ago
  Most of the reputable CAs have some practices in place to check for keywords related to big brands and auto-reject certificate requests. (So you can't get a certificate for "login-facebook.com" or whatnot, for instance.)
  - chetanahuja 11y ago
    There's no requirement in the spec for using "reputable" CA's for certificates.
  - johnnydoebk 11y ago
    Could you provide a few examples of reputable and not so reputable CAs?
    - rjaco31 11y ago
      Just browse the truststore of your browser, you'd be surprised.
  - chetanahuja 11y ago
    "(So you can't get a certificate for "login-facebook.com" or whatnot, for instance.)" You mean not from one of those "reputable" CAs. But really, why would I go to a "reputable" CA for my deceptive certificate if my intent is not so reputable?
  - rdancer 11y ago
    No, they don't. What would be the point, anyway?
    - duskwuff 11y ago
      Er, from personal experience I can say that at least some well-known CAs absolutely do review keywords appearing in SSL certificate requests. For a (really stupid and disappointing) example, see: http://forums.comodo.com/ssl-certificate-b14.0/-t106480.0.html http://forums.comodo.com/ssl-certificate-b14.0/-t106480.0.ht...
pakitan 11y ago
A valid certificate only allows you to have a secure connection without errors and warnings popping up all over. It does nothing to guarantee that the domain is "legit". You can already set up thecitibank.com and get an SSL certificate for it without any problem. What you can't do is get the EV (green bar) certificate where indeed you need to go through a human. But I'm pretty sure Let's Encrypt won't be giving away EV certificates.
- cpach 11y ago
  ”without any problem” Are you sure about that?
  - dtech 11y ago
    Most certificate providers are already fully automated, the personal identity (not domain ownership) verification is the only human part.
  - bigiain 11y ago
    Yeah - there's many ssl vendors who've automated everything - so long as you can read email sent to webmaster@whatever-damned-phishing-domain-you-like.com, they'll sign a csr for that domain's ssl cert.
- weavie 11y ago
  Surely you would at least need access to a relevant email address on that domain? How would you bypass that?
  - r0bbbo 11y ago
    He would need to be in control of that domain entirely. thecitibank.com is just an address that looks legitimate and is purchasable.
    - weavie 11y ago
      Ok, I understand. On a slight side note he may not necessarily need to control the domain entirely, just have access to a privileged email address [1] However, now it seems you won't even need access to an email address. What would stop someone creating a cert for the real citibank.com and using it for a MITM attack? How many people actually check the green bar? [1] http://arstechnica.com/security/2015/03/bogus-ssl-certificate-for-windows-live-could-allow-man-in-the-middle-hacks/ http://arstechnica.com/security/2015/03/bogus-ssl-certificat...
Russell91 11y ago
This comment is the exact perception about HTTPS that we need to change. It's not the job of HTTPS to say whether a website is safe or unsafe, good or bad. HTTPS should be the default communication protocol for every website, and lets encrypt move us a major step towards that by making SSL certificates free and trivial to set up.
- chetanahuja 11y ago
  "This comment is the exact perception about HTTPS that we need to change. It's not the job of HTTPS to say whether a website is safe or unsafe." Too late. The web industry has spent about 20 years training regular people to look for that green lock sign in the address bar and feel all warm and fuzzy about how safe the site is. You can post on hacker news all you want about what perceptions need to be changed. It's not going to change the ground reality. SSL, as practiced in the industry today with all it's historical baggage is fundamentally broken. There's no fixing it.
  - XorNot 11y ago
    Actually what's really broken is the way we've approached implementations. Recently I was trying to get a self-signed certificate for myself trusted by Python urllib3...I still don't know how to do it. It uses a completely separate trust-store. As does half a dozen other things on my system.
    - goldman60 11y ago
      Java is literally the worst as well. The Java truststore doesn't even have all the certs that every major browser supports. I'm looking at you StartSSL.
  - vacri 11y ago
    Green lock = EV cert. People are trained to look for the green, not for the lock - few people other than techies even look for a grey lock. EV certs generally have much more stringent requirements than "hey, give me a cert!".
stephenr 11y ago
As has been said, existing domain-validated (i.e. basic) certificates are automated anyway. The type of certificate that banks etc use are EV - Extended Validation. This means the organisation details are verified as well, and as such the browser displays the verified organisation name in green in some cases, instead of any host/url at all).
creshal 11y ago
Yes, you can. You can also do the same at every existing CA that provides domain verified certificates. From personal experience neither StartSSL nor Comodo have a human in the look – until you want more than domain verification (e.g., "green bar" EV certificates).
- bigiain 11y ago
  StartSSL at least have a human in the loop for your initial identity validation. They got in touch with me because I'd put a work address in instead of my home address, and they worked it out and sent me a very human-like email asking me to correct it.
  - alfonsoperez 11y ago
    I got also an email from a guy because my domain name had been registered that same day, telling me to wait, sure you can automate the check, but at least the email didn't look automated.

superuser2 11y ago

We don't have humans in the loop for issuing certificate; this can and has been exploited for fun and profit, with fun attacks like getting a cert for "citibank.com\0.mydomain.com" which used to trick the C strcmp in most browser certificate checking routines. Moxie has an entertaining talk: https://www.youtube.com/watch?v=MFol6IMbZ7Y https://www.youtube.com/watch?v=MFol6IMbZ7Y Your problem would be getting people to "thecitibank.com." Chrome, Firefox, and GMail would all eventually figure out it was a phishing site and warn users about clicking through to it.

cbg0 11y ago

Actually it's automated in most places, simply requiring you to confirm a request via an e-mail address associated with the domain you're getting an SSL for (typically admin@ hostmaster@ webmaster@, though it varies between certificate providers).

duskwuff 11y ago
Most of the reputable CAs have some practices in place to check for keywords related to big brands and auto-reject certificate requests. (So you can't get a certificate for "login-facebook.com" or whatnot, for instance.)
- chetanahuja 11y ago
  There's no requirement in the spec for using "reputable" CA's for certificates.
- johnnydoebk 11y ago
  Could you provide a few examples of reputable and not so reputable CAs?
  - rjaco31 11y ago
    Just browse the truststore of your browser, you'd be surprised.
- chetanahuja 11y ago
  "(So you can't get a certificate for "login-facebook.com" or whatnot, for instance.)" You mean not from one of those "reputable" CAs. But really, why would I go to a "reputable" CA for my deceptive certificate if my intent is not so reputable?
- rdancer 11y ago
  No, they don't. What would be the point, anyway?
  - duskwuff 11y ago
    Er, from personal experience I can say that at least some well-known CAs absolutely do review keywords appearing in SSL certificate requests. For a (really stupid and disappointing) example, see: http://forums.comodo.com/ssl-certificate-b14.0/-t106480.0.html http://forums.comodo.com/ssl-certificate-b14.0/-t106480.0.ht...

pakitan 11y ago

A valid certificate only allows you to have a secure connection without errors and warnings popping up all over. It does nothing to guarantee that the domain is "legit". You can already set up thecitibank.com and get an SSL certificate for it without any problem. What you can't do is get the EV (green bar) certificate where indeed you need to go through a human. But I'm pretty sure Let's Encrypt won't be giving away EV certificates.

cpach 11y ago
”without any problem” Are you sure about that?
- dtech 11y ago
  Most certificate providers are already fully automated, the personal identity (not domain ownership) verification is the only human part.
- bigiain 11y ago
  Yeah - there's many ssl vendors who've automated everything - so long as you can read email sent to webmaster@whatever-damned-phishing-domain-you-like.com, they'll sign a csr for that domain's ssl cert.
weavie 11y ago
Surely you would at least need access to a relevant email address on that domain? How would you bypass that?
- r0bbbo 11y ago
  He would need to be in control of that domain entirely. thecitibank.com is just an address that looks legitimate and is purchasable.
  - weavie 11y ago
    Ok, I understand. On a slight side note he may not necessarily need to control the domain entirely, just have access to a privileged email address [1] However, now it seems you won't even need access to an email address. What would stop someone creating a cert for the real citibank.com and using it for a MITM attack? How many people actually check the green bar? [1] http://arstechnica.com/security/2015/03/bogus-ssl-certificate-for-windows-live-could-allow-man-in-the-middle-hacks/ http://arstechnica.com/security/2015/03/bogus-ssl-certificat...

Russell91 11y ago

This comment is the exact perception about HTTPS that we need to change. It's not the job of HTTPS to say whether a website is safe or unsafe, good or bad. HTTPS should be the default communication protocol for every website, and lets encrypt move us a major step towards that by making SSL certificates free and trivial to set up.

chetanahuja 11y ago
"This comment is the exact perception about HTTPS that we need to change. It's not the job of HTTPS to say whether a website is safe or unsafe." Too late. The web industry has spent about 20 years training regular people to look for that green lock sign in the address bar and feel all warm and fuzzy about how safe the site is. You can post on hacker news all you want about what perceptions need to be changed. It's not going to change the ground reality. SSL, as practiced in the industry today with all it's historical baggage is fundamentally broken. There's no fixing it.
- XorNot 11y ago
  Actually what's really broken is the way we've approached implementations. Recently I was trying to get a self-signed certificate for myself trusted by Python urllib3...I still don't know how to do it. It uses a completely separate trust-store. As does half a dozen other things on my system.
  - goldman60 11y ago
    Java is literally the worst as well. The Java truststore doesn't even have all the certs that every major browser supports. I'm looking at you StartSSL.
- vacri 11y ago
  Green lock = EV cert. People are trained to look for the green, not for the lock - few people other than techies even look for a grey lock. EV certs generally have much more stringent requirements than "hey, give me a cert!".

stephenr 11y ago

As has been said, existing domain-validated (i.e. basic) certificates are automated anyway. The type of certificate that banks etc use are EV - Extended Validation. This means the organisation details are verified as well, and as such the browser displays the verified organisation name in green in some cases, instead of any host/url at all).

creshal 11y ago

Yes, you can. You can also do the same at every existing CA that provides domain verified certificates. From personal experience neither StartSSL nor Comodo have a human in the look – until you want more than domain verification (e.g., "green bar" EV certificates).

bigiain 11y ago
StartSSL at least have a human in the loop for your initial identity validation. They got in touch with me because I'd put a work address in instead of my home address, and they worked it out and sent me a very human-like email asking me to correct it.
- alfonsoperez 11y ago
  I got also an email from a guy because my domain name had been registered that same day, telling me to wait, sure you can automate the check, but at least the email didn't look automated.