Hidden Commands

Whenever you're hacking any public terminal of this type you have to remember that it's common to have different levels of security for potential us-ers of the system. With each level, the various commands may or may not appear listed in the menu - although you may still be able to activate them via an inadequacy in the
program. If a menu is given with options ranging from one to four -try five! And six... and zero too. Always try Z, Q, X, and other "weird" letters - anything else that has a possibility of working. It may not be enough to try these unlisted commands just once; sometimes you can have the program display an error message once or twice, and then suddenly crash out of the system or enter private territory. I grant you, usu-ally you won't find that programs have been so badly coded as to allow misuse, but you'd be sur-prised at the number of bugs that do go unnoticed by the authors and testers. This is especially true of early program editions.

Also, remember this: There are many functions you may not think would be on a library computer (or whatever computer it is you're working on). There may be mnemonics used which, on your own, you would never think of trying. So you must therefore try everything you can. What I mean is, let's say a library's PATs allow you to enter these three-letter commands to do different things: INQ (to make an inquiry on a book), NEW (to get new user information), and PAT (patron information, to find out about yourself). Naturally the system doesn't only support those three commands. There are dozens of other commands that you simply don't know about.

Try things like CON, ILL, CHG, DIS and other three-letter combinations (or whatever number of characters is appropriate). On some systems, all commands are three characters except for one called NEW USER or RECALL or something. If that's the case, then you know the computer will support commands of more than
three characters. Consequently, you should try longer commands as well. The commands I've chosen above are abbre-viations for CONversion, InterLibrary Loan, CHarGe and DIScharge, respectively. Before I told you what ILL stood for, you may have been won-dering how the word "ILLness" or "I Love Lucy" could have anything to do with a library. But ILL happens to be a very commonly used abbreviation.

 

To fool the PAT into believing you are feeding it bar codes,first (a) remove the light
penfrom the computer.
Then (b) plug the jack into a receiver that is connected to your laptop via the
communication port.
You can then output bar codes through the comm port, straight into the PAT.

If you're trying to break into a system you know nothing about, it's more than likely they'll use codes and abbreviations that are related to their field. Consequently, ongoing research is a must.

One United Kingdom system uses things like LCO and LIN for Library Check Out and Library INquiry. Also, due to certain overseas privacy laws, staff members are not supposed to access patron accounts to see personal information like addresses and phone numbers, and what books are checked out to patrons. This poses an obvious problem to the librarians who MUST know how to contact people who refuse to return borrowed items (and for countless others reasons, must know what items people have borrowed), so the people who wrote this library program installed a command that is invisible to EVERYBODY - even library employ-ees. Pressing "X" at the book inquiry screen will ac-cess a patron inquiry mode. This is something that
the library staff obviously knows about and uses, but is not supposed to have even heard of.

Anyway, the point is this: dumb terminals often include exits to controlling programs. You can ac-cess these secret parts by either issuing an exit command (a "trap door") and entering a password, or by entering a hidden menu item or command statement. Access may also be unintentional and due to an error, as with a program that lets you in even though you are not situated at a valid terminal, or have not entered the password.

It is also advisable to turn off the terminal, wait ten seconds, then turn it on again to see what hap pens. Some terminals respond to various combina-tions of Ctrl, Shift, and Alt. (Sometimes Alt is la-beled "Compose Character" because if you keep it pressed down while typing out a number 0-255 on the numeric keypad on the right side of the key-board, the corresponding ASCII character will be produced.)

Also look at the function keys, and combina-tions of Shift, Ctrl, etc., with the function keys. Try various other control codes like Escape, Ctrl-C, Ctrl-X, Ctrl-Q, Ctrl-G, Ctrl-Break, etc. You can never tell what's going to do something, or if anything unusual will happen at all. But sometimes you can get pleasantly surprised.