It depends on who attacker and defender are.

Excluding the modern equivalent of a script kiddie, even a "budget" attacker will have for sure invested enough to run a serious model (GLM 5.3 in this case, which requires hundreds of GB of RAM).

On the other hand - the defense - there is a large spectrum, and that's where the problem lies. There are surely companies that can defend themselves (either via cloud solution with granted cyber capabilities, or on local powerful machines), but there is a large amount of people that don't even know how to run a local LLM, let alone compile a program like Firefox.