Name: Russia’s Twitter throttling may give censors never-before-seen capabilities
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Russia’s Twitter throttling may give censors never-before-seen capabilities

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Russia has implemented a novel censorship method in an ongoing effort to silence Twitter. Instead of outright blocking the social media site, the country is using previously unseen techniques to slow traffic to a crawl and make the site all but unusable for people inside the country.Research published Tuesday says that the throttling slows traffic traveling between Twitter and Russia-based end users to a paltry 128kbps. Whereas past Internet censorship techniques used by Russia and other nation-states have relied on outright blocking, slowing traffic passing to and from a widely used Internet service is a relatively new technique that provides benefits for the censoring party.“Contrary to blocking, where access to the content is blocked, throttling aims to degrade the quality of service, making it nearly impossible for users to distinguish imposed/intentional throttling from nuanced reasons such as high server load or a network congestion,” researchers with Censored Planet, a censorship measurement platform that collects data in more than 200 countries, wrote in a report. “With the prevalence of ‘dual-use’ technologies such as Deep Packet Inspection devices (DPIs), throttling is straightforward for authorities to implement yet hard for users to attribute or circumvent.”The throttling began on March 10, as documented in tweets and from Doug Madory, director of Internet analysis at Internet measurement firm Kentik.In an attempt to slow traffic destined to or originating from Twitter, Madory found, Russian regulators targeted t.co, the domain used to host all content shared on the site. In the process, all domains that had the string *t.co* in it (for example, Microsoft.com or reddit.com) were throttled, too.Today's outages in Russia appears to have been caused by a bad substring match by .Intending to block Twitter's link shortener t[.]co, Russia blocked all domains containing t[.]co, for example Microsoft[.]com and Reddit[.]com.(H/T ) — Doug Madory (@DougMadory)That move led to widespread Internet problems because it rendered affected domains as effectively unusable. The throttling also consumed the memory and CPU resources of affected servers because it required them to maintain connections for much longer than normal.—Russia's executive body that regulates mass communications in the country—has last month that it was throttling Twitter for failing to remove content involving child pornography, drugs, and suicide. It went on to say that the slowdown affected the delivery of audio, video, and graphics, but not Twitter itself. Critics of government censorship, however, say Russia is misrepresenting its reasons for curbing Twitter availability. Twitter declined to comment for this post.Tuesday’s report says that the throttling is carried out by a large fleet of “middleboxes” that Russian ISPs install as close to the customer as possible. This hardware, Censored Planet researcher Leonid Evdokimov told me, is typically a server with a 10Gbps network interface card and custom software. A central Russian authority feeds the boxes instructions for what domains to throttle.The middleboxes inspect both requests sent by Russian end users as well as responses that Twitter returns. That means that the new technique may have capabilities not found in older Internet censorship regimens, such as filtering of connections using VPNs, Tor, and censorship-circumvention apps. Ars previously wrote about the servers .The middleboxes use deep packet inspection to extract information, including the SNI. Short for “server name identification,” the SNI is the domain name of the HTTPS website that is sent in plaintext during a normal Internet transaction. Russian censors use the plaintext for more granular blocking and throttling of websites. Blocking by IP address, by contrast, can have unintended consequences because it often blocks content the censor wants to keep in place.One countermeasure for circumventing the throttling is the use of ECH, or Encrypted ClientHello. An update for the Transport Layer Security protocol, ECH prevents blocking or throttling by domains so that censors have to resort to IP-level blocking. Anti-censorship activists say this leads to what they call “collateral freedom” because the risk of blocking essential services often leaves the censor unwilling to accept the collateral damage resulting from blunt blocking by IP address.In all, Tuesday’s report lists seven countermeasures:It’s possible that some of the countermeasures could be enabled by anti-censorship software such as GoodbyeDPI, Psiphon, or Lantern. The limitation, however, is that the countermeasures exploit bugs in Russia's current throttling implementation. That means the ongoing tug of war between censors and anti-censorship advocates may turn out to be protracted.You must to comment.

Russia has implemented a novel censorship method in an ongoing effort to silence Twitter. Instead of outright blocking the social media site, the country is using previously unseen techniques to slow traffic to a crawl and make the site all but unusable for people inside the country.Research published Tuesday says that the throttling slows traffic traveling between Twitter and Russia-based end users to a paltry 128kbps. Whereas past Internet censorship techniques used by Russia and other nation-states have relied on outright blocking, slowing traffic passing to and from a widely used...

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Ars Technica is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, science, technology policy, and video games. Many of the site's writers are postgraduates and some work for research institutions. Articles on the website are written in a less-formal tone than those in traditional journals. Ars Technica was privately owned until May 2008, when it was sold to Condé Nast Digital, the online division of Condé Nast Publications.

Russia’s Twitter throttling may give censors never-before-seen capabilities

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