I think you don't recall correctly, or perhaps you
never heard of the
Morris worm. It's been a while since I read up on it, but I'm fairly
sure one of its spreading mechanisms involved a VAX machine-language
grappling hook.
I would think the reason that the older machines do not have worms and
virus (generally) is that ciding them back then was simply not
in style. 20 years ago, if a worm was released for VMS, would it make the
news? Would anyone outside of a few thousand sysadmins really care? What
glory would there be for the hacker? Not much...
I think the "first" was written on a Univac system.