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This week, Google found unauthorized digital certificates for several Google domains, the root CA of which is CNNIC. Google and Mozilla both publicly disclosed this security incident and published blog posts(Google, Mozilla). However, Chinese translations of Google’s and Mozilla's blog posts were censored on the Chinese Internet.

• William Long is a prominent Chinese blogger on IT and tech. He translated Google’s security post without adding any personal opinions. The Chinese blogpost ranked #1 when searching CNNIC MITM in Chinese on Google and Baidu. He tweeted that he received a phone call from propaganda department demanding the post to be removed immediately. The post http://www.williamlong.info/archives/4183.html was deleted. Google cache is still available.

省政府新闻办打电话来称，“谷歌称CNNIC发布中间人攻击证书”一文需要立刻删除。

Since 2013, we have repeatedly called on major software vendors to revoke CNNIC-issued certificates. Most notably, we raised this issue when we reported on the Cyberspace Administration of China’s (CAC) man-in-the-middle (MITM) attacks on Google, Microsoft’s Outlook, Apple, Yahoo and Github. Mainstream media have reported about these security vulnerabilities before and on March 24, Ars Technica reported on Google’s announcement that they have definitive evidence that CNNIC (China Internet Network Information Center) was behind a new MITM attack on Google.

From our October, 2014 blog post:

We are under attack and we need help.

Likely in response to a recent story in the Wall Street Journal (WSJ), we’ve experienced our first ever distributed denial of service (DDoS) attack. This tactic is used to bring down web pages by flooding them with lots of requests - at the time of writing they number 2.6 billion requests per hour. Websites are not equipped to handle that kind of volume so they usually “break” and go offline.

This kind of attack is aggressive and is an exhibition of censorship by brute force. Attackers resort to tactics like this when they are left with no other options.

We are not equipped to handle a DDoS attack of this magnitude and we need help. Some background:

• The attack started on March 17 and we are receiving up to 2.6 billion requests per hour which is about 2500 times more than normal levels.

• This attack affects all of our mirror websites. While we have talked openly about our method of using collateral freedom to unblock websites and mobile apps that have been blocked by the Chinese authorities, the WSJ story clearly stated how the strategy works and how it is being used successfully to deliver uncensored content into China. Blocked websites that we have liberated in China include Boxun, Deutsche Welle and Google.

Recognizing that the authorities have been hesitant to crackdown on our method of circumvention, we have accelerated our expansion of the development of collateral freedom, in three key areas.

January 26, 2015

Beijing, China

 

Mr. Lu Wei

Director of the Cyberspace Administration of the People’s Republic of China 中央网络安全和信息化领导小组办公室主任

Director of the State Internet Information Office 国家互联网信息办公室主任

Deputy Director of the Central Propaganda Department of the Chinese Communist Party 中共中央宣传部副部长

Cyberspace Administration of China,

Floor 1, Building 1,

Software Park, Chinese Academy of Sciences,

4 South 4th Street, Zhongguancun,

Beijing, China, 100190

 

Dear Mr. Lu,

On January 22, 2015, the Cyberspace Administration of China (CAC), which is under your direct control, wrote a response to a story we published about an MITM attack on Microsoft. In the post, your colleague, Jiang Jun, labelled our accusations as "groundless" and  "unsupported speculation, a pure slanderous act by overseas anti-China forces".

We at GreatFire.org take great offense to these comments and we will refute them in this letter.

We do not level accusations against CAC lightly. We took great lengths to provide data collected during the attack to back up our claims. Multiple reports confirmed our analysis, including screenshots and tests posted by Chinese internet users as well as independent analysis from security experts.

On January 17, we received reports that Microsoft’s email system, Outlook (which was merged with Hotmail in 2013), was subjected to a man-in-the-middle (MITM) attack in China.

The following screenshot shows what happens when a Chinese user accesses Outlook via an email client (in this case, Ice-dove):

We have tested Outlook to verify the attack and have produced the same results. IMAP and SMTP for Outlook were under a MITM attack. Do note however that the web interfaces (https://outlook.com and https://login.live.com/ ) were not affected. The attack lasted for about a day and has now ceased.

This form of attack is especially devious because the warning messages users receive from their email clients are much less noticeable than the warning messages delivered to modern browsers (see screenshot at the end of this post for comparison).

(Sample error message from default iPhone mail client)

In the past, the Chinese authorities’ DNS poisoning system would direct Chinese internet users who were trying to access Facebook, Twitter and other blocked websites (without the use of a circumvention tool) to a set of fake IP addresses that are blocked in China or are non-existent. After waiting for some time, Chinese internet users would receive a timeout message if they were trying to access a blocked site.

However, with the new DNS poisoning system, in addition to those IP addresses used before, the Chinese authorities are using real IP addresses that actually host websites and are accessible in China. For example, https://support.dnspod.cn/Tools/tools/ shows that if a user tries to access Facebook from China, they might instead land on a random web page, e.g. http://178.62.75.99

Below is a screenshot by a Chinese user when he was trying to access our GreatFire.org website which was blocked in China. He was redirected to a goverment site in Korea. In essense, GFW is sending Chinese users to DDOS the Korea government's website.

One Chinese Internet user reported to us that when he tried to access Facebook in China, he was sent to a Russian website, unrelated to Facebook. Another user tweeted that he was redirected to an German adult site when he tried to access a website for a VPN.

某墙你这什么意思，DNS 污染返回给我一个德国工口站的 IP，满屏很黄很暴力弹弹弹（

— nil (@xierch) January 4, 2015