I don't think you even need to attack anybody to do this. Just have an AI media package ready for the top-N CEOs, and wait for any incident involving their name and "injured", "hospital", "attacked", etc. Then short the stock, go to social media and show the CEO being transported in an ambulance, or a gurney with a sheet over it, "X still missing", whatever.

Probably automatable, and simply counting on automated systems and panic selling. Might be possible just with the AI package these days (not even requiring a traditional media article).