g3proxy: Ability to change ClientHello sent to upstream server

[mspublic]

When using g3proxy it is sometime detected by websites running on cloudflare and other sites using TLS fingerprinting such as https://github.com/salesforce/ja3. Having the ability to modify the ClientHello will make the proxy less detectable/less fingerprintable and more usable in enterprise environments.

The ideal “solution” would be to be able to set a ja3 fingerprint and have the proxy send it.

I have not found a way to modify it via OpenSSL but it appears rustls may give access to the ClientHello https://docs.rs/reqwest/latest/reqwest/struct.ClientBuilder.html#method.use_preconfigured_tls

Here is a bit more info and code examples:

https://medium.com/cu-cyber/impersonating-ja3-fingerprints-b9f555880e42

https://github.com/refraction-networking/utls

https://github.com/Danny-Dasilva/CycleTLS

https://github.com/LyleMi/ja3proxy

https://github.com/Kolosok86/http-tls-proxy