4 ms·
I did some research, write-up and scripting about the state of X.509 Name Constraints, so that people you give your CA cert to don't need to trust you not to Mi
by nh2 2y ago
I did some research, write-up and scripting about the state of X.509 Name Constraints, so that people you give your CA cert to don't need to trust you not to MitM them on other domains.
Packaged into a convenient one-liner to create a wildcard cert under for the new .internal TLD.
Please scrutinize!
I use this to provide e.g. at home:
https://octoprint.myhome.internal
https://paperless.myhome.internal
to provide transport encryption of these services in the local WiFi.
Friends and family can add the CA root to their devices without having to worry about me MitM'ing their other connections.
- ulfbert_inc 2y agoNiklas, if you are reading this - it was a pleasure to interview with you some 6 (or so) years ago :) thanks for the script and the research, I will make use of it.
- nh2 2y agoThanks Vadzim, I remember -- happy to be useful :)
- vbezhenar 2y agoIs it possible to constrain existing CA? For example my government uses non-standard CA and some websites rely on it. But importing CA obviously makes them able to issue google.com and MITM me if they want to. And they already tried, so trust is broken. I imagine something like generating separate name-constrained certificate, sign existing CA with this name-constrained certificate (I think it's called cross-sign or something like that) and import things into OS, expecting that browser will use name-constraints of the "Root-Root" certificate. Could it work?
- deleted 2y ago[deleted]
- dinosaurdynasty 2y agoNamecoin has made utilities similar to this (in order to constrain all existing CAs from signing `.bit` domains) so I assume so.
- poincaredisk 2y agoYes, I do it in my work to restrict my company CA to company servers [1]. You generate your own CA, and cross sign other cert with any constraint you want. It works great, but requires some setup, and of course now you have your own personal CA to worry about. [1] Yes, company is ok with it, most of my team does it, and this makes everyone more secure. Win-win.
- dfox 2y agoI assume that the mentioned “some setup” involve not only distributing the new root CA, but also somehow prepopulating the old cross-signed certificate, as the services know nothing about that and thus will not send it in their cert chain. Or am I overlooking something?