There is without a doubt a variation of this prompt you can pre-test to successfully bait the LLM into exfiltrating almost any data on the user's machine/connected accounts.
That explains why you would want to go out and buy a mac mini... To isolate the dang thing. But the mini would ostensibly still be connected to your home network. Opening you up to a breach/spill over onto other connected devices. And even in isolation, a prompt could include code that you wanted the agent to run which could open a back door for anyone to get into the device.
Am I crazy? What protections are there against this?
Social, err... Clanker engineering!
This is something computers in general have struggled with. We have 40 years of countermeasures and still have buffer overflow exploits happening.
A buffer overflow has nothing to do with differentiating a command from data; it has to do with mishandling commands or data. An overflow-equivalent LLM misbehavior would be something more like ... I don't know, losing the context, providing answers to a different/unrelated prompt, or (very charitably/guessing here) leaking the system prompt, I guess?
Also, buffer overflows are programmatic issues (once you fix a buffer overflow, it's gone forever if the system doesn't change), not an operational characteristics (if you make an LLM really good at telling commands apart from data, it can still fail--just like if you make an AC distributed system really good at partition tolerance, it can still fail).
A better example would be SQL injection--a classical failure to separate commands from data. But that, too, is a programmatic issue and not an operational characteristic. "Human programmers make this mistake all the time" does not make something an operational characteristic of the software those programmers create; it just makes it a common mistake.