i will add this because someone mentioned software on here and perhaps its not worth a topic on its own but is something that all cnc machinists should bare in mind in relation to there controllers and software. This is relevant to anyone using a controller card thats assessable to the network, or anyone using windows on any part of there network.

The Americans and Israelis and us ( uk ), wrote a totlay different type of virus call stuxnet to attack Iran's infrastructure, specifically to attack semen's controllers,motor drivers,VFD and operating systems, through holes in usb/bios/Os backdoors ( holes that the americans forced the co,s to include ). When Iran found it ( many trashed centrifuges later ), they published the code. and i dont think nobody considered the consequences. The way it was coded to move around undetected, and locate targets, and implement itself was new, and still is reasonably untraceable. The first few modules in teh code can be adjusted to vary the attack parameters, the modules that attack the VDF timers arent specific to semens, they mess with teh way the chip calculates/times,

OK< YOU SAY, WHATS THAT GOT TO DO WITH CNCing

Because as soon as them craft hackers got hold of it they realised they could use the code to load onto any usb or cd or disk, to find and attack many different types of micro-controllers. A real lot of stuff coming out the east and ru has this coding hidden on it someware, if the cd spins or usb powers the drive, it will infect it without trace. The real problem is it has the capability to infect the routers underground ( infrastructure ), and these arent easy to replace. IE, if it infects ANY machine connected to the same infrastructure point as you ( usualy a few hundered connections ), it will infect all of them. and its only detectable when it activates.

OK, whats relationship with CNCing

Because my friend has seen many many different variations on this used to attack American and Chinese products, ( seems like there is some sort of cyber spat on between them ). a lot of the codes seems to be directed towards overheating the chips.

The point being , be very wary about exposing you cnc computer to the net, any hacked software, and eastern disk. And if it is exposed to the net, dont let your microcontrollers identify themselves ( especially LAN connections ).