@Don't Panic
> 3) the control frequencies are not interfered with. Those are highly secure, and come from multiple redundant points.
Maybe you have inside information, but we're left to assume this is the case. For all we know it could be just as insecure.
> 4) hacking a drone, even if you could decrypt the signal, not only would rely on getting it to respond, but you'd have to know intimate details of the control signals.
Nobody should make this mistake, especially not the military. It's called security by obscurity. It doesn't work, just ask Skype.
> 5) it's not one computer, but 3, running on different hardware platforms and running on different OS. ALL THREE have to generate the same response at the same time in order for it to accept input. If one system goes rogue because it's been hacked, the other two ignore it, and the operator is informed a computer is down.
Again, maybe you have inside information, but this is presumptuous. And your paragraph contradicts itself internally. In your scenario, only two would need to be hacked. If it's the same application software being run on various platforms, it is likely that the application is equally vulnerable on each platform. If it's three separate application implementations, though not impossible, it would be incredibly difficult to ensure that each generates the exact same responses at the same time. This added complexity could actually increase the failure modes should the applications behave differently during a hack.
Besides, unless there are three separate control channels, it only needs to be hacked once to control all three implementations.
> Honestly, this is not a big deal.
I'm not panicking, but it is at the very least an embarrassment to have such a trivial vulnerability.