So to me it seems like the prime candidates to come up with stuff like this are researchers working in defense and similar fields, probably not some deranged lunatic in a basement. And certainly not a rogue AI on its own.
Given the recent HF hack it seems likely that human-level intelligence could identify a fair number of avenues of attack, with some time and effort. To say nothing of anything superhuman.
Unfortunately it seems like we can't assume we can "box" the AI (e.g., deny it connection to the Internet) and expect that to last. The AI safety people used to run scenarios imagining ways the AI might convince humans to let it out of the box. It turns out that many humans will eagerly pull it out without the AI doing anything at all, aside from the human knowing the AI's power. Or the one responsible for setting up the box will somehow fail, or just not bother and then lie about it.
Of course we can do that. It's not an eternal being of light existing on the astral plane, but some code executing on someone's GPU.
It stops existing once you press Ctrl + C