This question has also been asked on Server Fault, but was not taken seriously. I hope this is a better place for it
I'm going to install Debian Wheezy on a KVM VPS. VNC access to console is enabled, and by sniffing network traffic when connecting, I see VNC password is encrypted but everything else is sent in plain text. It's possible to install Debian remotely over SSH by loading the "network-console" component early in the installation process. After configuring the network, a dialog asks for "Remote installation password"
I can then connect to the installation with
ssh email@example.com and continue the installation over an encrypted connection. However, the remote installation password has to be typed while connected via VNC, and is therefore sent in plain text. An attacker who sniffs the password can then compromise the installation.
What is the best method in this case to avoid an attacker compromising the installation?
Before typing the remote installation password it's possible to execute a shell. However, the installation environment is very limited so only few commands are availiable. I think the best option is to restrict SSH connections to only my IP address, but this do not seems to be possible.
Another option I have thought about is quickly connecting to the installation after typing the remote installation password, and then remove the "installer" user from /etc/shadow thereby avoiding others from logging in, but not sure if this is safe enough. I hope there are more options I haven't thought of.