What are the odds that this was a cyberterrorism attack? If you can predict this kind of market event (the bounce back), and you want to hurt a company and its users, you would simply DDoS at the right time.
If you can predict this kind of market event I imagine you've got better things to do.
Well, all you have to predict is that the market will move - the direction wouldn't matter much, since the brokerage has customers trying to do both calls and puts.