Tested across 11 vantage points in 9 Chinese cities against 77 Alexa-ranked websites (50 trials each, April–May 2017), most prior TCB evasion strategies are largely broken: TCB creation with SYN achieves only 6.9% success (88.9% Failure 2), TCB teardown with FIN achieves only 11.1% success (87.9% Failure 2), while in-order data overlapping with TTL-based insertion still achieves 90.6% success and only 3.7% Failure 2. Without any evasion strategy the baseline success rate is 2.8%.
From 2017-wang-your — Your State is Not Mine: A Closer Look at Evading Stateful Internet Censorship
· §3, Table 1
· 2017
· Internet Measurement Conference
Implications
Prioritize in-order data overlapping (buffer-prefill) over out-of-order or TCB-creation strategies when targeting the GFW; the former degrades gracefully while the latter have near-zero efficacy against the evolved GFW.
Treat TCB teardown with FIN as broken and remove it from any production circumvention tool targeting China.