And regardless, it was a hard, cheap, early lesson in the importance of ensuring fundamental levels of system security. I've ... suffered worse.
I strongly suspect you'll never forget this.
But scripted or not, someone did you a favor.
For a reference point, a (very technical) friend at a large tech company had to fire up a fresh Windows VM in order to complete some Windows/IE-only internal web app form.
He was p0wned within 5 minutes. On the corporate LAN. Stats I've seen are that an unpatched WinXP box (pre-SP2) was getting p0wned within 15 seconds, on average by the mid/late oughts. Scripted attacks are that fast and easy.
Scanning an IP range for open telnet ports (n00b move #1) and attempting root logins on same (n00b move #2) with weak passwords (third strike) is pretty trivial. Could have been another AOL user, could have been someone's IRC bot / autoattack.
While not blaming the victim, you discovered (on a freshly installed, no-real-data-present-yet box, hence, very inexpensively) that You Don't Do That[tm].
So: stop crying over this and put on your Big Boy pants. That asshole did you a favor. Really.
In what world do you think that
1) I'm 'still crying' over something that happened 17 years ago by relating it in a comment
2) It's appropriate to tell other professionals relating a story to 'stop crying'
It's certainly not this one.
I am saying that, yes, he did something stupid and got spanked for it.
I'm also saying (and in my highly downvoted follow-up providing additional examples of) that it's reasonably if not highly plausible that the attack was wholly scripted and automated.
I've been burned myself -- by systems stuff as well as meatspace events. Very often the key finding of a particular experiment is "don't do that".
That was my point.
I was 9 or 10 years old at the time and my root password was one of those common strings (12345, abcde, I don't remember at this point). It had taken me 3 days to learn how to download Linux, make a stack of installation floppies, find and use partitioning tools, install Linux and set up a boot loader, etc. I cried when I realized what had been done to me.