I definitely think it’s plausible for AI designed with malicious intent to wreak havoc in the ways OP mentioned. We’re entering into a phase where there’s thousands of new and competing AI’s popping up. At least a handful of them will undoubtedly be weaponized. I’m actually terrified of the new cybersecurity threats that will emerge (of course there will be “good” AI’s working against malicious actors, but we’re entering uncharted territory).