China has started filtering and censoring internet traffic taking place over the QUIC protocol.
The filtering started in April last year.
The Great Firewall now decrypts QUIC packets at scale and uses a separate blocklist for QUIC traffic, separate from its main filters
Exposing and Circumventing SNI-based QUIC Censorship of the Great Firewall of China
Since April 2024, the Great Firewall of China (GFW) has been censoring QUIC traffic to specific domains. Our findings show the GFW decrypts QUIC Initial packets at scale and employs a unique blocklist. Our research reveals this system is ineffective under heavy traffic loads and it can also be weaponized to block arbitrary UDP traffic. In response, we collaborate with various open-source communities to integrate circumvention strategies into Mozilla Firefox, the quic-go library, and all major QUIC-based circumvention tools.
GFW Report (gfw.report)
