On Russia’s Early Introduction of QUIC SNI Censorship

Governments around the world limit free access to information through Internet censorship. With the rising adoption of the QUIC protocol, these censors have been forced to evolve their systems. Russia introduced sweeping changes to its censorship after its full-scale invasion of Ukraine, including completely blocking international QUIC connections. However, after this broad filter was identified in 2022, Russian QUIC censorship received little attention: The current state of QUIC censorship by TSPU devices is largely unknown. In this paper, we provide a timeline of Russian QUIC censorship and detail its current state. We identify that Russian TSPU devices switched to SNI-dependent QUIC censorship on a large scale between May 2022 and July 2023, a fact that went largely unnoticed for three years. While the GFW was previously thought to be the first censor with broad SNI-dependent QUIC censorship, we highlight that Russian TSPU devices broadly adopted SNI-dependent QUIC censorship at least nine months before the GFW. We consider this an indicator of the TSPU devices’ flexibility and of Russia’s willingness to invest in strict and up-to-date censorship.