Some protection is to have only one shared folder on your computer that is controlling CNC machine.
Any malicious "viruses" or gremlins will be contained only in that folder.
I don't have any antivirus/antimalware program on a computer that is controlling my router. Just one shared folder on a partition that is not the system one
BTW I'm running Mach3 on WinXP and bCNC when using blue laser controlled by GRBL.