Consider a wireguard network of many clients which all interact with each other through a central hub server on a cloud VPS. One of the clients is a desktop used for SSHing into the other various clients–again, through the central hub. If the “terminal” client connects to another client through the wireguard hub using SSH public/private key authentication, what if any information within that SSH tunnel gets exposed or leaked to the “hub” server?

My threat model is if the VPS was to ever get compromised. I previously SSH’d into the hub VPS server and from there I would SSH into any of the other clients with a password. Horrible security, I know.

My new setup is as mentioned above. Only the single desktop client has key authentication to SSH into the various clients. But I want to be sure none of that data gets exposed to the VPS hub just in case.