All the attention has been on software security, of extracting the next marginal vulnerability out of heavily-scrutinized large codebases. In the actual professional field of infosec, that's a speciality; another specialty is network pentests and red-teaming, which exploits misconfigurations and seeks out weakest-link software (rather than exhaustively fishing for the next kernel LPE or whatever).
Red teaming and netpen work is probably substantially easier for models than software security; it costs less context, but is also much more explicitly an implicit search problem where win conditions are just spotting stupid stuff that humans missed.
My visceral reaction to this is that with the right harness, you probably could have replicated this with an open-weights model last year. (I'm saying this as confidently as I am because a CGC team leader agreed with me about it yesterday).
I think people forget that the harness work we're considering here --- I don't know anything about OpenAI's harness or ExploitGym or whatever --- are basically not new; people have been developing automated exploitation and pivoting toolkits for decades, and scanners long before that. So the idea of a tool getting 0.0.0.0/0 as a target list instead of 192.168.1.0/24 and then busting up a bunch of random people's computers: not really very startling.
Obviously, LLMs give those kinds of scanners an intentionality they wouldn't have had before. But as a person who keeps a computer science perspective on security stuff, I don't know that it gives them capabilities they didn't have.