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I'd agree. We have plenty of CAs - killing a few off here and there isn't going to harm our ability to manage certificates, and those that make these kinds of m
by cheald 14y ago
I'd agree. We have plenty of CAs - killing a few off here and there isn't going to harm our ability to manage certificates, and those that make these kinds of mistakes - intentionally or otherwise - aren't worth the trouble of having them around.
A couple of CAs being revoked for slipping the wrong certs to the wrong parties is only going to make other CAs triple check their work before handing out the keys to the kingdom.
- tptacek 14y agoNo, it won't harm our ability to manage certificates. What it will do instead is create a point in time where suddenly a whole mess of websites that used to be protected with HTTPS are now no longer protected with HTTPS. If there's a graceful and safe way to provide effective advance notice for this, I haven't heard it yet. I agree in spirit; I'd like to see more CA's get the death penalty. But the pragmatic argument against it is convincing.
- cheald 14y agoThis seems like a problem that could be pretty easily solved by the browser vendors, similar to how they do malware checks. Throw up a "this site's security certificate was issued by a compromised authority, and will no longer be valid in <x time at y date>. If this is your website, click here for more information." Run that for a sufficiently long period of time, then kill the CA. It's not perfect, but we have a huge web of people using these affected sites on a daily basis who can serve as a very powerful driving force to spur change when necessary to minimize fallout.
- sc68cal 14y agoWhile I agree with you about pulling the rug out from users - if the CA is already forging certificates for important domains, then how much security do they really have?
- dustingetz 14y agoright now only the turkish government can do MITM - other parties can't.
- jacquesm 14y ago> right now only the turkish government can do MITM - other parties can't. First, if true that's a small comfort. Second, how do you know that is true?
- danielweber 14y agoIt's in the Turkish government's to use these invalid certs as little as possible, so they are probably going to use them against people like Turkish dissidents. (I don't mean to dismiss their interests, but they are distinct from other people's interests.)
- tptacek 14y agoMore than they do if the whole CA is removed. Sorry, annoying but true. Promote TACK!
- geofft 14y agoAs a future mitigation strategy, what about encouraging website owners to have certificates independently signed by multiple CAs? Perhaps require multiple CAs for EV certs, and maybe for certain HSTS sites? This makes it easier to revoke a bad CA and harder to spoof a high-value certificate, and _also_ gives the CAs more revenue, which sounds like a win-win situation for everyone. :-)
- tptacek 14y agoBecause that is more effort for much less benefit than TACK.
- geofft 14y agoTACK only helps with clients that have seen a site before, right?
- danielweber 14y agoYes, but that's most sites. This leaves an attack vector against people doing first-time-ever connections (like fresh installs of new OSes that are grabbing their new security packages), but TACK pins can also be pre-loaded or shared between clients for those circumstances.
- deleted 14y ago[deleted]
- dustingetz 14y agoChrome could warn "XYZ CA is scheduled to be marked untrusted in 30 days". The sites large enough to have economic impact if they were unsecured would notice and scramble to get new certs. Other browser vendors would follow. A warning shot is fired paving a path for harsher penalties in the future.
- iigs 14y agoI'd argue that as long as an intermediate is passing out BS certs, nobody (modulo cert pinning etc) who trusts that intermediate or its root is truly protected.
- mikeash 14y agoI don't quite understand the "no longer protected with HTTPS." If their certificates stop working as part of the CA's revocation, then they'll have to get new ones before they can continue operating over HTTPS, of course. But they won't somehow automatically revert back to HTTP or anything, they just won't be able to carry on business (or at least their users will have to click through scary warnings). So they'll be offline for, what, a few hours, days at most, while they get this sorted out? And never actually insecure, just inaccessible.
- tptacek 14y agoHTTPS without a verified certificate (ie, after clicking through the warning) is only cosmetically more secure than HTTP.
- briffle 14y agoThis is kind of funny. The connection is still encrypted from others that might see it in-flight (ie, coffee shop, etc). However, your right, you would not be able to verify that the person on the other end was really the one you wanted to. However, this discussion is here because someone had one that WAS perfectly valid for gmail.com, even if it was not actually owned by google.
- tptacek 14y agoYes, but in the current situation only a small subset of people were exposed to that certificate, whereas killing the CA outright exposes everyone to bogus certificates for the CA's domain.
- rmc 14y agoThe connection is still encrypted from others that might see it in-flight (ie, coffee shop, etc) Not really. If you were using your laptop on wifi in a coffee shop, I could intercept your traffic and rewrap the SSL in my SSL. You then have no way to know if you're securely talking to me, or to the original site.
- stock_toaster 14y ago
- ctz 14y agoI think a known subset of websites having their HTTPS broken as a result of their CA misbehaving is much more preferable to a single CA having effectively broken all HTTPS for all internet users since 2011. It's not a clear dichtomy, though: harsh penalties rarely alter behaviours.