Comment by cloudsec9

At our school, the "computer" teachers were often teachers who were specialists in other areas that had some interest in computers, and weren't very ... security aware. They all had admin/root user access, and they'd often forget to sign out, leaving us with the keys to the kingdom, at least temporarily.

We figured out how to create a SUID shell, so we could get back to root even after we head logged out. Poking a few bytes would have been more interesting!