Live data from Hacker News

Github SSL replaced by self-signed certificate in China

news.ycombinator.com

21–30 of 78 posts

Re: Github SSL replaced by self-signed certificate in China

#21
post #20

I was wondering when Github was going to start supporting HSTS and 2-Factor Auth. I'm betting that it gets bumped in priority after this event. Nothing like an incident to move along security requirements! http://dev.chromium.org/sts https://www.duosecurity.com/features

Why use duosecurity over something like RFC 6238 and RFC 4226?

Re: Github SSL replaced by self-signed certificate in China

#22
Fortunately, it looks like Chrome prevents users from clicking past the ssl errors. This Chinese chrome screenshot[1] shows that there's only a back button (for English versions of this page, see [2]). Unfortunately, it appears that IE allows users to click past the errors[3]. I'm also interested in how the 360 browser[4], which has been gaining market share in China, handles the error.

Does anyone have any theories why China would use a self signed certificate when it's very indiscreet? A lot of users will just click through if given the opportunity (around 60% in chrome before new security measures prevented it[2]), but I doubt many users with truly sensitive private repos would do this.

[1] https://twitter.com/GreatFireChina/status/295236912594186240...

[2] http://www.imperialviolet.org/2012/07/19/hope9talk.html

[3] https://twitter.com/chenshaoju/status/295139636718743552/pho...

[4] http://news.ycombinator.com/item?id=4499168

Re: Github SSL replaced by self-signed certificate in China

#23
post #20

I was wondering when Github was going to start supporting HSTS and 2-Factor Auth. I'm betting that it gets bumped in priority after this event. Nothing like an incident to move along security requirements! http://dev.chromium.org/sts https://www.duosecurity.com/features

I don't think either would help in this situation. HSTS helps prevent SSL stripping attacks, which whoever is denying SSL access to GitHub doesn't need to bother with.

2FA serves as an annoyance to phishers, but whoever is doing this network attack has direct access to your session cookie.

Re: Github SSL replaced by self-signed certificate in China

#24
post #19

To clarify, this looks more like someone turning off SSL access to GitHub than a proper MITM attack in the traditional sense. The certificate in that link is just a self-signed certificate, not something signed by a CA: Issuer: C=US, ST=Some-State, O=github.com, OU=github.com, CN=github.com Subject: C=US, ST=Some-State, O=github.com, OU=github.com, CN=github.com So your browser will warn you that you are not making a…

Thanks, Moxie - The original article in China (by top-notch geeks) wrote 中间人攻击 which translates directly to "man-in-the-middle attack".

Appreciate your insight - thanks for weighing in on this.

Re: Github SSL replaced by self-signed certificate in China

#25
post #19

To clarify, this looks more like someone turning off SSL access to GitHub than a proper MITM attack in the traditional sense. The certificate in that link is just a self-signed certificate, not something signed by a CA: Issuer: C=US, ST=Some-State, O=github.com, OU=github.com, CN=github.com Subject: C=US, ST=Some-State, O=github.com, OU=github.com, CN=github.com So your browser will warn you that you are not making a…

I don't think there's proof of China doing anything here. Perhaps someone on OP's coffee shop WiFi is poisoning arp tables and forging certs.

This seems really sloppy for China. Without further proof, I don't think it was the govt.

Re: Github SSL replaced by self-signed certificate in China

#26
post #5

This reminds me the Firefox certificate "bug"[1] two years ago. A China certificate root server was added into trusted servers in Firefox and Chinese hackers started to submit bug report regarding this, since people don't trust certificate servers run by China government. Man-in-the-middle attack was exact what Chinese hackers worried about. If they put this fake certificate in a certificate root server that's in the…

Spoofing GitHub's SSL certificate is a step in the direction of inserting espionage-style backdoors, as GitHub permits HTTPS read-only checkouts of repositories. I'm not suggesting that this will be free of problems, given how particular Git is about checksums, nor am I certain what methods they would use to acquire SSH commit access for altering repository contents to affect the rest of the world. Still, it's absolu…

GitHub now [allows HTTPS pushes][1], so a man-in-the-middle attack on a single connection would be sufficient to push backdoors. In any case, can't the intermediary just add another SSH key to the account?

[1]: https://help.github.com/articles/pushing-to-a-remote

Re: Github SSL replaced by self-signed certificate in China

#27
post #20

I was wondering when Github was going to start supporting HSTS and 2-Factor Auth. I'm betting that it gets bumped in priority after this event. Nothing like an incident to move along security requirements! http://dev.chromium.org/sts https://www.duosecurity.com/features

We've supported HSTS for for well over a year now.

Re: Github SSL replaced by self-signed certificate in China

#28
post #10

It sucks my client will be able to say he was right about now allowing source code to be hosted on github. (We ended up setting up a gitlab box and it works just as well)

What exactly is he right about? China hasn't done anything that you can't do on a local WiFi connection. They grab the connection and put a self-signed cert to it. Security is still intact. The only way this hurts anyone is if they blindly trust all certificates, in which case they're screwed anyways.

Re: Github SSL replaced by self-signed certificate in China

#29
Many are mentioning the Chinese government, but are there any signs that they are involved?

How do we know that this isn't just a hijack of a Chinese isps dns server or something similar? Maybe the same that happened to Goolge Morocco just a couple of days ago ( http://arabcrunch.com/2013/01/breaking-google-morocco-google... ).

Re: Github SSL replaced by self-signed certificate in China

#30
Some speculation as to why they're targeting Github:

- the Chinese gov't is trying to identify users/developers of train-ticket-purchasing bots [1]

- they are is interested in capturing some intellectual property contained in private repos

- it's just an exercise to watch & learn how computer-literate users circumvent a MITM attack

Given the recent Github blockade, I'd go with the first.

[1] http://www.techinasia.com/github-blocked-china/

Post reply on HN