Ineptly Censoring the Chinese Internet - Yet Again

Green Dam filtering code said to be ineffective and copied from U.S. software maker Solid Oak

2 min read

Heavy-handed filtering of pornography and political speech, security holes, and accusations of theft of intellectual property - if that sounds to you like the Chinese Internet of 2005 you're exactly right.

But according to news reports, it also describes the Chinese Internet of 2009. Back in 2005, as part of our special issue on China, we reported on how China's nationwide filtering of pornography and political speech worked. That system relied on filters residing within the country's central servers and routers. This year, China is adding a twist - requiring that filtering software come on every new PC sold. Originally, computers would have had to actually run the software; after a huge national and international outcry, the government has backed down, as has been reported in The Gardian and by the AP

The software, written by a military contractor, closes some loopholes in the central filtering approach that were apparent even in 2005, such as the use of proxies to redirect users from blocked sites to unblocked sites that contain the same censored content. But Green Dam, as the software is named, is apparently problematic in every other possible way. For example, according to the Guardian, the pornography image-blocking

is designed to identify suspicious densities of skin colour. To demonstrate the supposed effectiveness of this method, the bid document contrasts pictures of blow jobs and babies.... [But the] Southern Weekend newspaper has mocked the software for blocking Garfield cartoons but allowing dark-skinned porn.

Problems with Green Dam first came to light in an analysis by three researchers in the University of Michigan's Computer Science and Engineering Division, Scott Wolchok, Randy Yao, and J. Alex Halderman. Their chief finding involved the security problems:

We have discovered remotely-exploitable vulnerabilities in Green Dam, the censorship software reportedly mandated by the Chinese government. Any web site a Green Dam user visits can take control of the PC.

According to a number of reports, the Chinese government has reportedly ordered the developer to issue a patch. China Daily quotes the developer as sheepishly saying, “We are specialists in producing Internet filtering software rather than security."

Yet there's also the question of how much of the software the developer developed. Solid Oak Software, has claimed that Green Dam includes code swiped from its censorship program CYBERsitter, and the U.S. company has, according to PC Magazine, “sent 'cease and desist' letters to both Dell and Hewlett-Packard” asking them to stop distributing Green Dam.

If, as is now being widely reported, the software is compulsory only in that it be present on all PCs, not that it be installed and operating, then Green Dam won't be the nightmare it might have been. It certainly wasn't the first heavy-handed assault on the massive freedoms brought to the Chinese people by PC and Internet technologies.

Nor is China the only country to employ blacklists and filters. Last week my colleague Bob Charette pointed out that ”the Australian government has also embarked on a program to filter (or 'boil the ocean' as some have called it) the Internet.” And my 2005 article noted that even the United States is hardly free of crude and heavy-handed Internet content filtering. As long as there are governments and powerful channels of communication, the two will be at loggerheads.

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