Re:Cry Wolf (Score 1)

It's not the software install you would have to be worried about.

If I wanted to bug a PC (x86 based) that I was manufacturing, I'd use System Management Mode. If they're manufacturing the PC, they're probably manufacturing the BIOS as well which would allow them to setup SMM.

That way the host OS can't detect anything since the system is stopped while SMM is active. You could sniff traffic, log keystrokes or whatever else you wanted to do. Then just wait for a phone-home signal, the night cleaning crew, etc... to arrive and offload the collected data.