mike2@lcuxa.UUCP (04/24/87)
[yum, yum]
First, thanks to those of you who answered my plea for help. Although
it turned out to be unnecessary (see below), I appreciate it.
Second, since not everyone got hardoff.com when I posted it, I am
reposting it now. It's short.
Third, it turns out that "hardon.com" is created by hardoff.com when
the latter is run, and "hardon.com" erases itself when it is invoked.
That is why I did not have a copy of it. My face is red. It shows
how often I've used it.
Fourth, just so that no one gets too sanguine...
a. Hardoff will protect the hard disk from a Trojan that
seeks to access it, at least on normal INT21 dos calls. It looks like
it also does so for lower level BIOS calls (e.g., INT13), but I am not
certain of this. It probably won't protect against a truly
sophisticated Trojan that manipulates the ports themselves in ML (e.g.
using the OUT/IN commands, but such programs would not be too portable
and probably would not be distributed by the kind of psychotic that
wishes to cause the maximum amount of harm to the maximum number of
people).
b. If the Trojan is working in ML, it undoubtedly will
suppress BIOS or DOS-generated error indications of the nature of
"trying to access a non-existent drive." Thus, even if a suspected
program "passes" a hardoff.com test, that does **not** mean that when
the hard drive is activated thereafter that it is safe to run the
program. When I thought this one through I abandoned using hardoff,
and that probably is the real reason I forgot how it works.
For those who want it:
1. ORIGINAL "DOCUMENTATION":
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[[ [[ [[[[ [[ [[ [[ [[ [[ [[ [[ [ [[ [
[[ [[ [[ [[ [[ [[ [[ [[ [[ [[ [[ [ [[ [
[[[[[[ [[ [[ [[[[[ [[ [[ [[ [[ [[[[ [[[[
[[ [[ [[[[[[ [[ [[ [[ [[ [[ [[ [[ [ [[ [
[[ [[ [[ [[ [[ [[ [[ [[ [[ [[ [[ [[
[[ [[ [[ [[ [[[ [[ [[[[[ [[[ [[[[ [[[[
This utility program is great for avoiding the dangers of those TROJAN HORSE
programs that we BBS users live in fear of. When you run HARDOFF.COM, your
hard disk is temporarily turned off (inacessible). Also hardoff.com creates
another program called hardon.com. Running this turns your hard drive back
on.
When your hard disk is turned off, you can feel at ease running any
downloaded software from your floppy disks knowing that no reading or writing
to C: drive can occur.
NOTE : HARDOFF.COM & HARDON.COM MUST BE RUN FROM THE FLOPPY DISKS. If by
chance you have a problem, simply reboot your machine and the lock
will be removed.
Metal Man 10/09/86
---------------------------------CUT-----------------------------------
2. Program:
begin 600 hardoff.com
MZS20ZP0`````N00`N```CL"_3`"^`@'SI.L+:&%R9&]N+F-O;0"Z&`&X`4.Q
M`,TAM$'-(<T@NAL!N0$`M#S-(8O8L3.Z`P&T0,TAL0"Z`@"X`$+-(;@``+$$
FCMBR3+1`S2&X``".P([8_+$$O@`!OTP`K*KB_+0^S2'-(`````#-
`
end
3. Disclaimer:
I'm passing this on (again) as received, and there are, of course, no
warranties express or implied. Use this at your own risk, or, in
light of the comments above, don't use it at all!
Mike Slomin