Msg: 2367 *Conference*

04-15-92 12:01:32

From: RICHARD HANSON

To : JON SHURTLEFF

Subj: REPLY TO MSG #2366 (WARM)

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Jon: It's actually quite easy to make changes in DOS commands, etc.  The DOS
shell, COMMAND.COM, can be altered using a HEX editor tool, i.e., PCTOOLS.EXE.
I demonstrate this "mystery" to my classes by editing DIR to HUH.  Once edited,
simply run COMMAND.COM, or reboot the computer, and the new commands take
effect.  It's sort of nifty to change the DOS commands and be the absolute,
only one who can access your computer.  Given the above example: Issue the
command DIR and you get "Bad command or filename".  Couple this with changing
DEL to XXX, and ERASE and other distructive commands to something else, then
set the prompt to the old-style terminal prompt (PROMPT $_ or PROMPT $: ...this
is the UNIX and CICS prompt) and you've got real security.
 
Another nice feature of editing DOS utilities is the ability to install "hidden
features" that show up later.  Example: The FORMAT.COM utility, used to prepare
new diskettes, places the words "Non-System disk" on all non-bootable
disks--there's more to the prompt, luckly--room for creativity!  When someone
just happens to have a data disk (non-system disk) in the boot drive (drive A:)
when they reboot their computer they get the message placed on the disk when it
was formatted.  Many, many folks go for years without seeing that prompt, or
see it a few times a year.  In any case, this is one place that you can have
fun with.  My personal favorite is, "This ain't no DOS disk, dork face!".  I
find that prompt quite amusing and have planted the "seed" in many places.
Granted, it's rude but definately non-distructive... physically, of course.  I
usually do this to my.... freinds!
 
Your "friend" ... -Rick-