The company is searching for excuses to limit their own responsibility for the crash. Reasonable questions that emerge are, as was mentioned before: what OS and soft they are using on the mission critical hardware and why? Do they use some cheap desktop OS and soft, or alike, to save some money in expense of people's safety? Probably the plane manufacturing company should be held responsible here. And they should be sued as for using cheap inappropriate materials. No comment on possible conection of mission critical hardware to a public network.
What's about suing hacker/s/ who wrote the mallware - good idea actually, but you probably should consider also suing the gun manufacturers for shootings.