While I was at my first co-op job and fortunate to have multiple computers at my disposal (on essentially a gov't related domain) I also spent a fair amount of time hanging out in IRC chat (I think #chat2)... This was 1995.

Anyway, some "script kiddie" (not literal as he was an adult) had downloaded a script to cause a netsplit and take over the chatroom giving himself mod rights upon re-join, kicking everyone in the room and then locking and pw-protecting the channel.

I had recently been serving on a tiger team (ad hoc group of friends that would hack servers for fun and then leave messages for the admins on how to secure their servers).

So I looked at the channels this guy was in on IRC. He was in some hacker related channel... which I joined. He was bragging about having "taken over" in #chat2 (SERIOUSLY?!?!?!)... I scanned his info and quickly determined his server. Using a pretty basic exploit I connected to his server (he was using his company's machine... I think he was an IT Director or something)... the idiot used the same username on IRC as he did on his work machine... and guess what... he also used that same username as his password!!! (IT DIRECTOR????)

So, now having an account on his machine, I grabbed the pw file and ran it through a dictionary tool. I quickly had root access.

I changed the root pw and his user account pw.

Then I connected to IRC from his machine and joined the hacker channel... I started calling him out for being a total n00b (I wasn't much more than one myself, honestly, but I was clearly ahead of this guy)... he was flaming back at me and then I said "fine, go ahead and check my address"...

Of course everyone in the room checked and they all started laughing at the guy... he literally said in the room "how are you logged in from my machine?" then "WTF"... I mentioned that he was going to have a hard time explaining this to his boss since his root pw was changed... then the computer disconnected (presumably turned off)...

We didn't hear from him again in #chat2...