Using SSLproxy to downgrade TLS 1.3 to TLS1.2

[odehneh]

Hello

Is it possible to use SSLproxy in the following scenario:

• Client sends a TLS 1.3 ClientHello
• SSLproxy transparently intercepts the request, downgrade to TLS 1.2 and forwards it to the server without decrypting it
• SSL proxy receives the Server response and forwards it to the client as TLS1.2

The downgrade objective is to use a URL filter that supports only TLS 1.2

client ---(TLS1.3/1.2)-- SSLproxy ----(TLS1.2)--URLF --(TLS1.2)----server

(I read somewhere that this is actually an attack and that TLS1.3 has some defense mechanism for it, so may be I'm just hoping)

If the answer is yes, do you have an idea about how much traffic can SSLproxy can handle in this scenario?

Omar

[sonertari]

*SSLProto rules in global, proxyspec, and filterrules config apply to both client and server sides. So I don't think SSLproxy can do that. But, I think that may happen if client or server chooses different protocols, which is not under your control.