State-endorsed web browsers turn out to be bad news

Making the headlines in the tech world this week has been evidence of someone trying to man-in-the-middle Chinese iCloud users:

Unlike the recent attack on Google, this attack is nationwide and coincides with the launch today in China of the newest iPhone. While the attacks on Google and Yahoo enabled the authorities to snoop on what information Chinese were accessing on those two platforms, the Apple attack is different. If users ignored the security warning and clicked through to the Apple site and entered their username and password, this information has now been compromised by the Chinese authorities. Many Apple customers use iCloud to store their personal information, including iMessages, photos and contacts. This may also somehow be related again to images and videos of the Hong Kong protests being shared on the mainland.

MITM attacks are not a new phenomenon in China but this one is widespread, and clearly needs substantial resources and access to be effective. As such, it would require at least government complicity to organise and implement.

Of course, modern browsers are designed to avoid exactly this problem. This is why the Western world devotes so much effort to implementing and preserving the integrity of the "certificate chain" in SSL - you know you're connecting to your bank because the certificate is signed by your bank, and the bank's signature is signed by a certificate authority, and your browser already knows what the certificate authority's signature looks like. But it seems that in China a lot of people use Qihoo 360 web browser. It claims to provide anti-virus and malware protection, but for the past 18 months questions have been asked about its SSL implementation:

If your browser is either 360 Safe Browser or Internet Explorer 6, which together make up for about half of all browsers used in China, all you need to do is to click continue once. You will see no subsequent warnings. 360's so-called "Safe Browser" even shows a green check suggesting that the website is safe, once you’ve approved the initial warning message.

I should note, for the sake of clarity, that both the 2013 and the current MITM reports come from greatfire.org, whose owners leave little doubt that they have concerns about the current regime in China. A proper assessment of Qihoo's 360 browser would require it to be downloaded on a sacrificial PC and used to check out websites with known problems in their SSL certificates (e.g. self-signed, out of date, being MITM'd). For extra points you'd download it from a Chinese IP. I don't have the time or spare machine to test this thoroughly, but if anyone does then I'd be interested in the results.

Anyway, if the browser compromise checks out then I'm really not surprised at this development. In fact I'm surprised it hasn't happened earlier, and wonder if there have been parallel efforts at compromising IE/Firefox/Opera/Chrome downloads in China: it would take substantial resources to modify a browser installer to download and apply a binary patch to the downloaded binary which allowed an additional fake certificate authority (e.g. the Chinese government could pretend to be Apple), and more resources to keep up to date with browser releases so that you could auto-build the patch shortly after each new browser version release, but it's at least conceivable. But if you have lots of users of a browser developed by a firm within China, compromising that browser and its users is almost as good and much, much easier.