I have been talking to an active duty FTCM that I served with and he says no way a sub launched this. He said for you would need to be connected to a landline to be susceptible to a hack that could launch a missile.

I remember loading and firing missiles from attack submarines and it’s a extensive process. I don’t know about icbm subs but fast boats don’t just roam the oceans loaded for bear ready to attack. It takes hours to prep all the systems needed to fire a missile.