I have a dedicated machine for my wallet now. Yes, the wallet was created offline and will NEVER be online. I’m going to reformat the compromises machine anyways just in case who ever it is can’t attack anything else.
Discussion
On all your Linux machines:
1. Enable firewall.
2. Install, run, and learn Opensnitch (it's easy).
3. Periodically run clamav, rkhunter, and chkrootkit.
Desktop operating systems by default trust the network too much; the above will help you verify, instead.