Not as smart as everyone thinks it is, maybe, but a model like Fable 5 without safeguards against offensive cyber attacks would be a nightmare. There are millions of improperly secured web applications that, in the wrong hands, would be easily exploited by these models.

There have been millions of trivially exploitable vulnerabilities out there for decades — many of which could be easily discovered by using simple scanning tools or manual probing. This is hardly a new situation and LLMs really aren't that impressive at pentesting — even with these simple exploits. Maybe they are if you're not a pentester, but then ZAP, Burp, Nessus, SQLMap, etc. are likely also impressive if you put a little effort into learning how to use them, but many AI-advocates aren't interested in learning skills themselves.

It's the same situation as with vibe coding. Everyone and their grandma can have an LLM spit out a web application without any programming experience, but if you're a programmer, you'll likely quickly see some issues with maintainability and further development of the code base.

In a substantially different way then how it is now? You can put something listening on 22, 80 and 443 and log how much stuff tries to get in.