TOM-Skype Logs

I received a request regarding the types of logs that TOM-Skype keeps and have seen some discussion around what Skype could possibly be keeping. (For background on TOM-Skype censorship and surveillance practices, see Breaching Trust: An analysis of surveillance and security practices on China’s TOM-Skype platform and blog posts here, here and here.) While my report focused on the “content filter” logs that contained the text of chat messages there were a variety of other logs:

• contentfilter*.log – ip, username, message, date, time (+ unknown parameters)‏
• skypecallinfo*.log – ip, username, version, username/phone number, date, time (+ unknown parameters)‏
• skypelogininfo*.log – ip, version, username, date, time
• skypenewuser*.log – ip, version, username, date, time
• skypenewusersendmoneytest*.log – unable to decrypt
• skypeonlineinfo*.log – ip, username, version date, time (+ unknown parameters)‏
• skypeversion*.log – version, ip, date, time (not encrypted)‏

The function of each logs is pretty self-explanatory based on the name of the file. In addition to the “contentfilter” logs, the “skypecallinfo” logs were very important as these files contain a record of who called who (skype usernames or phone numbers). In total, between the “skypecallinfo” logs and the “contentfilter” logs there are upwards of 4.5 million unique skype usernames or phone numbers in the logs I was able to download.

This doesn’t tell us anything about possible wiretapping with Skype or whether or not voice calls (other than the call data record in “skypecallinfo”) can be logged in other ways. Still, in many cases just knowing who is talking to who is as valuable as the content of the conversation itself.

Watching the Watchers

The Irish Times reports:

CHINA’S TOP surveillance tsar has been has been arrested for taking bribes and framing a business rival, a move that has inspired and gratified both local bloggers and foreign journalists used to stultifying censorship regulations, and prompted questions at senior levels of the Communist Party about how the “Great Firewall of China” is enforced.

Unfortunately, the article itself has some of the typical nonsense seen in many articles about surveillance in China such as:

But China has tens of thousands of “net nannies”, who read every e-mail, web posting or search for “Dalai Lama”, and they are a huge impediment to reporting in China.

I wish they’d think about what “read every e-mail” means.

Surveillance was a Chinese Gov’t Requirement — Skype

I raised questions in the “Breaching Trust” report regarding why TOM-Skype started to log their users’ messages and who had access to the data? Skype now says that the monitoring was a Chinese government requirement. Now we know why it was done and who had access to the captured messages.

Skype President Josh Silverman writes:

What have you learned from TOM about the uploading and storing of certain chats, and what are you doing about it?

What we have discovered in our conversations with TOM is that they in fact were required to do this by the Chinese government.

“Extremely Concerned” — Skype

UPDATE: Skype President Addresses Chinese Privacy Breach — Josh Silverman’s statement on the Skype blog.

The AFP reports:

Skype said it learned just Wednesday that a previously disclosed text filter operated by TOM-Skype, a joint venture between Chinese mobile firm TOM Online and Skype, had been altered.

“Last night, we learned that this practice was changed without our knowledge or consent and we are extremely concerned,” Skype, which is owned by US online auction house eBay, said.

“We deeply apologise for the breach of privacy relating to chat messages on TOM’s servers in China and we are urgently addressing this situation with TOM,” the company said.

AFP

Skype president Josh Silverman said in a statement that TOM Online “just like any other communications company in China, has established procedures to meet local laws and regulations.

“These regulations include the requirement to monitor and block instant messages containing certain words deemed ‘offensive’ by the Chinese authorities,” Silverman said.

“It is common knowledge that censorship does exist in China and that the Chinese government has been monitoring communications in and out of the country for many years,” he said.

He recalled that in April 2006, Skype admitted that TOM Online “operated a text filter that blocked certain words in chat messages” and unsuitable messages were to be “discarded and not displayed or transmitted anywhere.”

“It was our understanding that it was not TOM’s protocol to upload and store chat messages with certain keywords, and we are now inquiring with TOM to find out why the protocol changed,” he said.

“We are currently addressing the wider issue of the uploading and storage of certain messages with TOM,” Silverman said, stressing that the millions of people around the world using standard Skype software were unaffected.

TOM-Skype Q & A

I have been getting a lot of questions and feedback on the “Breaching Trust” report. I’ll try to post more details and answer questions. Here are some of the common questions people have been asking.

How were you able to determine that messages containing keywords were being uploaded to a web server? How did you find and decrypt the messages?

Wireshark. Every time I typed the word “fuck” an HTTP connection was made to a TOM Skype server. I visited the URL directly in Firefox, cut off the file name and was able to view the contents of the directory. With a little poking around I found the encryption key. A few lines of Python and voila. I did not “crack” anything nor was there any “elite” hackery — just plain, simple stuff.

Is “normal” Skype affected?

No. The Skype software downloaded from skype.com is not affected by the behavior. The only time “normal” Skype users are affected is when they communicate with TOM-Skype users.

What is TOM-Skype and what is the difference between it and Skype?

If you go to www.skype.com from China, you are redirected to skype.tom.com — so that’s version most Chinese people will use.

In 2004 Skype developed a relationship with TOM Online, a leading wireless provider in China, and announced a joint venture in 2005. Skype and TOM Online produced a special version of the Skype software, known as TOM-Skype, for use in China.

What is Skype saying, have they said anything to you?

I contacted Skype to have the security issue fixed before the report was released. So, they have configured the servers so that one can no longer view the logs and they have deleted sensitive files, such as the one containing the encryption key. Other than that contact, I’ve only seen the
statements they’ve made to reporters.

The NYT:

Jennifer Caukin, an eBay spokeswoman, said, “The security and privacy of our users is very important to Skype.” But the company spoke to the accessibility of the messages, not their monitoring. “The security breach does not affect Skype’s core technology or functionality,” she said. “It exists within an administrative layer on Tom Online servers. We have expressed our concern to Tom Online about the security issue and they have informed us that a fix to the problem will be completed within 24 hours.” EBay had no comment on the monitoring.

To the WSJ

Jennifer Caukin, a spokeswoman for Skype, said in an emailed statement that the security problem had been remedied as a result of the new report. The idea that China’s government “might be monitoring communications in and out of the country shouldn’t surprise anyone,” Ms. Caukin said. “Nevertheless, we were very concerned to hear about the apparent security issue” that enabled people to view user information, and “we are pleased that, once we informed TOM about it, that they were able to fix the flaw.”

In a separate statement, TOM Group said that “as a Chinese company, we adhere to rules and regulations in China where we operate our businesses.”

The WSJ blog, has the statement in full.

In the past Skype stated:

The text filter operates on the chat message content before it is encrypted for transmission, or after it has been decrypted on the receiver side. If the message is found unsuitable for displaying, it is simply discarded and not displayed or transmitted anywhere.

What I found directly contradicts this.

How does this relate to Corporate Social Responsibility (and the voluntary Principles of Free Expression and Privacy process)?

This case demonstrates the critical importance of the issues of transparency and accountability by providers of communications technologies. It highlights the risks of storing personally identifying and sensitive private information in jurisdictions where human rights and privacy are under threat. It also illustrates the need to assess the security, privacy and human rights impact of such a decision.

Some companies, such as Google, has stated that while the censor some search results they “will not maintain on Chinese soil any services, like email, that involve personal or confidential data.”

In this case Skype appears to have delegated all of the censorship and surveillance responsibilities to TOM – I don’t think they read Rebecca’s paper; they should. While examining the Yahoo! China – Shi Tao case she warned:

Companies that choose to ignore the broader human rights implications of their business practices are gambling with their long-term global reputations as trustworthy conduits or repositories of people’s personal communications and information.

Are the “key words” censored? Or are the messages just logged?

The only key word that I could use to trigger the content filter (the messages is not displayed to the user) and have logged in the content filter logs (uploaded to the tom-skype server) was “fuck” (and variations like f*ck). If a message contains the word “fuck” it is not displayed to the user (the entire message is not displayed) and the entire message is uploaded and logged.

In the same content filter logs I found that the majority of the logged messages did not contain obscenities, like fuck. However, many of the messages contained words like “Communist Party”, I counted the number of logged messages that contained these words, from that I identified what I think are key words. It is unclear if these messages are just logged, or are censored and logged.

Post questions in the comments and I’ll try to answer them :)