Back then hacking machines was soooo easy. i mean hell you could just tap into the phone line and listen to commands if you wanted then have all you need. But also back then you could usually brute force most things too.
The world was so much smaller you could literally even brute force phone numbers if you didnt know them. It used to be that phone numbers were rather orderly such that the first 3 digits was a region, the next 3 were a sub-region, and then the last 4 were randomly assigned within that region. So if you know the location of something you didnt even need to know the phone number, you would do what was called war dialing and would just randomly dial every number in the subregion and mark off each one that responds with automated tones and then you'd have narrowed down your choices to like 5 - 20 things and that was every possible computer in the area. Then just hack them all and see what is what.
It was a simpler time :)