In the paper they say that the worm uses either existing vulnerabilities that it has been trained on or new published vulnerabilities that it scrapes. 44% claimed success.
The paper is a bit silent on why a such a worm would need an LLM. It seems that brute forcing all known vulnerabilities, script kiddie style on each new machine is about the same.
But apparently that info is too dangerous to release ...
AV/EDRs are kinda lame but "brute force all known vulnerabilities" is definitely something they can detect.