biskup that is a very unpleasant scenario but as long as a large portion of miners are divers machines (different os, patched versions, etc.) then the attack surface is rather difficult to gain a large portion at one time before the miner operators notice (no more coin being delivered for work, etc.)
I'm just speculating, I know it smells a bit like conspiracy theory.
More to say, such hack won't be possible with ASIC based hardware unless... the manufacturer delibarately puts some malicious code inside... But, it's just another speculation.
