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China is now blocking all encrypted HTTPS traffic using TLS 1.3 and ESNI
- 1MachineElf 6y agoUp until now, I thought "The Great Firewall" was limited to layer 2, layer 3, and just layer-7 DNS controls. The capability described in this article sounds more like a full layer-7 MITM. That's terrifying. Is any HTTPS secure within mainlan China's networks? Or am I misunderstanding, and it's just the government websites that are blocking incoming TLS 1.3 connections?
- Legogris 6y agoSome further explanation here: https://geneva.cs.umd.edu/posts/china-censors-esni/esni/ https://geneva.cs.umd.edu/posts/china-censors-esni/esni/ Looks like it's L4?
- msmith 6y agoThat link was fascinating to me. For as long as I remember, there have been tools to evade network intrusion detection systems and stateful firewalls, but I never thought about how the same techniques can be used to evade censorship.
- dylz 6y agoGFW has been all layer for a long time, including actively re-probing and connecting back to a server from random (really, virtually any CN IP space). HTTPS is somewhat secure, but subject to MITM. Most Chinese forks of browsers ignore certificate errors and allow everything through.
- unicodepepper 6y agoWould I be safe from this type of MITM attack if my browser respects SSL warnings? (and I don't bypass them)
- aaomidi 6y agoGenerally yes. But remember with SNI they know exactly what website you're visiting.
- aaomidi 6y agoThis is our fault for taking so long with ESNI.