That is actually a very good question that I have been wondering. With the
wireless system inside a computer being like an invisible bridge to connect
other systems, it might not be totally paranoid to think that a hardware hack
could attack a computer through that. I am not talking about "service X
running and listening to data coming from other PC". I mean like "sending
certain signals that would make the hardware itself react in certain ways,
enabling certain spying activity". But for that the only solution would be
open-source hardware with a thorough security audit.
Or maybe the NSA guys know :P
Anyway, for now, the best is to have ufw configured to deny all incoming
connections. Disable remote access and maybe install DenyHosts. No more ideas
:S