In an effort to prevent people from circumventing internet censorship, the Turkish government blocked access to Tor. According to TurkeyBlocks, the government imposed an immediate 12-hour ban on Tor, VPNs, and social media. The social media and messaging services made their way back online after the 12-hour mark, but the Tor ban remains blocked.
TurkeyBlocks monitors internet censorship in real time and announces changes via their website and Twitter account. On December 18, the organization posted a tweet confirming the limited or slow access to major social media accounts. Additionally, they announced and confirmed that the government blocked Tor.
On the TurkeyBlocks website regarding the social media network restrictions:
The Turkey Blocks monitoring network has detected severe slowdowns affecting Facebook, Twitter, YouTube and WhatsApp for some, but not all, internet users in Turkey. Access timings show that the restrictions began around 8:45 PM local time and ended 6:00 AM the morning after. (TurkeyBlocks).
The social media update mentioned the possible connection between the blackout and the recent assassination of the Russian ambassador to Turkey. “The social media shutdown comes shortly after the fatal shooting of Russia Ambassador to Turkey Andrei Karlov and the imposition of a national broadcast ban,” the post concluded.
Ever since the government issued the Tor ban, according to TurkeyBlocks, users in Turkey experienced some difficulty accessing the network. Tor stayed alive, though—despite the government requesting weekly updates from ISPs regarding Tor and the Tor ban.
Last month, the government announced a prohibition on VPNs, social networks, and Tor. Turkey implemented Internet restrictions long ago; that was not news. However, the acknowledgment that more and more individuals used Tor and VPNs to bypass censorship made headlines. Officials ordered internet service providers to begin implementing the ban. According to a local news report, “Turkey asks providers to block: Tor Project, Master, HotspotShield, Psiphon, Zenmate, TunnelBear, Zero, VyprVPN, Espress, IPVanish, Private.”
The ISPs work began paying off on December 18. See TurkeyBlocks update:
Turkey Blocks finds that the Tor direct access mode is now restricted to most internet users throughout the country; Tor usage via bridges including obfs3 and obfs4 remains viable, although we see indications that obfs3 is being downgraded by some service providers with scope for similar on restrictions obfs4. The restrictions are being implemented in tandem with apparent degradation of commercial VPN service traffic. (TurkeyBlocks)
Alp Toker, the founder of TurkeyBlocks, announced that this ban was unusual—even in light of Turkey’s renown censorship laws. The government issues an official broadcast to ISPs with websites that needed immediate banning, but many ISPs failed to block any sites. He said this could be a technical failure or intentional non-compliance to fight the censorship. He added that a refusal to comply could be “due to contention about Russia’s role in Syria—we do not know at this point.”
“Everything we have seen suggests the Tor/VPN block is here to stay, not a measure that gets switched on or off at request… So that is a pretty serious escalation,” Toker said.
Users are still able to connect via Tor bridges, TurkeyBridges announced. Some users lost direct access to Tor—those who used TTNet and UyduNet for internet service. While the organization used phrasing that left something to be said, they announced the ISPs implemented Deep Packet Inspection. The DPI disrupts the connection to Tor at the 10% mark. They also found that once a user made a successful connection to the network, subsequent connections happened seamlessly. The reason for this, they said, was the cached values that the service formerly wrote to temporary files. “This means that existing Tor users with a primed cache may be able to connect directly despite the blocking measures, they said.”
While the government blocked the ability to use Tor with a default configuration, options are still available. We wrote an article on bypassing the ban above. “Pluggable Transports for Tor: Dodging Censorship.”