>The login prompt could easily be spoofed by a user-mode program.
On the VT100 terminals in the computer lab in college (back in the early 90s) someone was doing this. A shell script to harness logins, print it was unsuccessful and log out. .
There was a key at the top of the vt-100 keyboard that would reset it. The "key" part was often pried off (accidental pressing was bad), but you could still press the nub left behind.
In my misspent youth I wrote a login trojan for VAX/VMS. It circumvented the "break" key trick that you are alluding to above. I had to drop down to Bliss-32 and use the $QIO syscall but it can be done. Once I had captured the sysadmin password and logged in once to prove my achievement I never ran it again. Learned many interesting things though. My task was made easier because DEC published the source code for the OS, albeit as Microfiche. I was therefore able to study the terminal handler code and figure out how to make a trojan that perfectly emulated the regular login behavior including all its timeouts and responses to various control keys.
Oh, and the VAX-11/780 I had hacked into crashed due to a memory board fault in the minute after I had logged in with my snagged admin password. I spent the remainder of the weekend sweating that I had broken the VAX since I had no idea what had happened. I had just given myself all 32 of the VMS account privileges when it went down.
My guess would be that you did using the microfiche reader at your university or at a library. Before digitization, such devices were fairly common wherever people had a lot of text to archive.
(Aside: https://en.wikipedia.org/wiki/Microform even has a photo of a “DuKane brand microfiche reader with source code printed on the films.”. I couldn’t read enough of the text on the envelope to decide whether that is true from the photograph
On the VT100 terminals in the computer lab in college (back in the early 90s) someone was doing this. A shell script to harness logins, print it was unsuccessful and log out. .
There was a key at the top of the vt-100 keyboard that would reset it. The "key" part was often pried off (accidental pressing was bad), but you could still press the nub left behind.