Ken Thompson's Unix Password
I remember cracking the password from a Windows system in high school. There was a centralized login mechanism using Novell but everything was cached locally. So you could boot a Linux CD and copy the password file to a memory stick, and crack at home. I think I used lophtcrack? The head admin account for the entire school district (basically root) had the password “north”. It took like a fraction of a second to crack. It was so simple that for weeks I didn’t even believe it to be true, and didn’t realize the name of the account was an admin.I was expelled a few months later for all the fun I had after discovering this. Good times.