                RUMORS OF WORMS AND TROJAN HORSES
               Danger Lurking in the Public Domain

               introduced and edited by Mike Guffey

-INTRODUCTION

There are literally thousands of free (or nearly  free)  programs
available in computerdom's Public Domain. Those who use them save
hundreds of  dollars  and  thousands of hours.  But many sneer at
the  idea of anything  worthwhile  being  "free".  Thus  personal
computing becomes divided into two camps: those who believe there
are two camps and the rest who use  Public  Domain  software (but
sport no sense of moral superiority).

For several years now  rumors  have  circulated  about  dangerous
programs  which,  when  run,   infest  the  innards  of  personal
computers  like  parasites.   And  unlike  most  software,  these
insideous programs don't go away when the power is shut off.  The
story  is  they  invade  ROMs  and "eat" memory  away  each  time
hardware is powered up.

The legends have a basis in fact.  For such horrors =do= exist in
the world of mainframes.  Probably first  created  by  a bored or
disgruntled programmer, such programs  have been unleashed inside
some  of  this country's largest computers.  Generally, they  are
not outwardly visible, but begin the  attack  like  a  low  grade
fever.   And these horrible little strings of code  do  damage  a
little at a time, slowly building in intensity.  At first, things
start going slightly awry.   Ultimately,  the  system  crashes or
must  be  shut  down.  One recent magazine article  called  these
creations "computer viruses".  Just =how=  damaging such programs
can be (or have  been)  has  not  been fully publicized.  But the
facts  lie   on  a  razor's  edge  between  science  fiction  and
tomorrow's  headlines.   They are  believed  to  pose  a  serious
potential threat to national security.

Some say the first of such monsters appeared on computer bulletin
boards  (BBS's)  named  "WORM.COM".  [Remember  that  it is  only
recently that any online descriptions began to be posted next  to
program names.  Some  BBS's, notably CP/M based systems, still do
not offer any explanation beyond the program name or notes in the
associated message base part of the system.]   And  almost  every
computer user  group  has at least one experienced member who can
tell  the  horrible  tales  of  what  these  programs do.  Actual
witnesses to the destruction or victims of the atrocities seem to
be =very= rare.

Related to  the twisted thinking behind such criminal mischief is
the so-called "TWIT" phenomenon.   Twits are computer vandals who
glory  in  breaking  into  and  "crashing" or seriously  damaging
remote computer  systems.   The  targets  range from neighborhood
BBS's to any large  computers  which  can  be  accessed via phone
lines.  And while such  mental midgets have bee·hglorified in the
media and mis-labeled as  "hackers",  their very existence causes
hysteria in and amongst the non-computing public at large.

Computer security for  large and small remote computer systems is
getting better at screening out or scaring off "twits". But  they
still exist.  There are indications that some have graduated from
incessant attempts to break into BBS's. Instead  they bring forth
Trojan  horses:  damaging  programs  disguised as  utilities  and
mis-labled  or  misdocumented as  new  treasures  of  the  Public
Domain.
                            ===]#[===

The following data was recently retreived from a California BBS:

WARNING! DANGEROUS PROGRAMS

1)  Warning:  Someone is [or may be] trying to destroy your data.
Beware  of  a  SUDDEN upsurge of [spurious] programs on  Bulletin
Boards and in the Public Domain.  These  programs  purport  to be
useful  utilities,  but,  in  reality,  are designed to sack your
system.

One has shown up as EGABTR, a program that claims to show you how
to maximize the  features  of IBM'S Enhanced Graphics Adapter. It
has also been  spotted renamed as  a new super-directory program.
It actually erases the  (F)ile (A)llocation (T)ables on your hard
disk, [thereby rendering all data useless and inaccessible].  For
good measure, it asks you to put a disk in Drive A:, then another
in Drive B:. After it has erased those FATs too, it displays,

                     "  Got You! Arf! Arf!  "

Don't [casually] run  any  public-domain  program  that  is not a
known quantity.  Have  someone  you  know and trust vouch for it.
ALWAYS  examine  it  FIRST  with  DEBUG  [or  DDT  or  a  similar
utility].  Look at all the ASCII  strings  and data.  If there is
anything even slightly suspicious about it, [either] do a cursory
disassembly [or discard it].   [For  MSDOS  programs]  be wary of
disk  calls  (INTERRUPT  13H),  especially  if the program has no
business writing  to  the  disk.   Run your system in Floppy only
mode with write protect  tabs  on  the  disk or junk disks in the
drives.

Speaking  of  Greeks  bearing  gifts,  Aristotle  said  that  the
unexamined life is not worth living.  The unexamined program [may
not be] worth running.

- from The Editors of PC
  July 23, 1985
  Volume 4, Number 15


2) Making the rounds of the REMOTE BULLETIN BOARDS [is] a program
called VDIR.COM. It is  a little hard to tell what the program is
suppose to do.

What it actually does is TRASH your system.   It  writes  garbage
onto  ANY  disk it can find, including hard disks, and flashes up
various messages telling you what it is doing.  It's a TIME BOMB:
once run, you can't  be  sure  what  will  happen next because it
doesn't always do anything immediately.  At a later time, though,
it  can  CRASH  your system.  Anyway,  you'd  do  well  to  avoid
VDIR.COM. I expect there are a  couple  of harmless, perhaps even
useful, Public Domain programs floating about with the name VDIR;
and,  of course, anyone warped enough to launch this kind of trap
once,  can  do  it  again.   Be  careful  about  untested  "free"
software.

[paraphrased from
 Computing at Chaos Manor
 From the living Room
 By Jerry Pournelle
 BYTE Magazine, The small systems Journal]


Two other examples of this type of program:

1. STAR.EXE presents a screen  of  stars  then copies RBBS-PC.DEF
and renames it.  The  caller  then  calls  back later and d/l the
innocently  named file, and he then has the SYSOP'S and  all  the
Users passwords.

2. SECRET.BAS This file was left on an RBBS with a message saying
that the caller got  the file from a mainframe, and could not get
the file to run on his PC, and asked someone to try it out.  When
it was executed, it formatted all disks on the system.

We must remember, that there are a few  idiots  out there who get
great   pleasure   from   destroying  other  peoples'  equipment.
Perverted  I know, but we, the serious computer users, must  take
an active part in fighting against this type of stuff, to protect
what we have.  Be sure  to  spread  this [message] to other BBS's
across the country so that as many  people  as  possible  will be
aware of what is going on.

[from
The Flint Board
Flint, Mich
(313) 736-8031]
                            ===]#[===

-EPILOGUE

Got your attention?  There is no need  to  hatchet your modem and
erase  your communications software.  While such programs can  do
tremendous  damage,  they   are,  fortunately,  very  rare.   The
following  is  an  expansion  of  the  countermeasures  suggested
above.

A)  Never, NEVER, N>E>V>E>R>!  download  and  run  Public  Domain
software (the first time) on a hard disk.   While  many  programs
are  well  known,  it  is  a  logical  presumption  that   Trojan
horse-type  programs may have been uploaded with the  name  of  a
well-known  utility.   Or  as  a  new version of one of your  old
favorites.  Download them to a blank floppy or to a disk you have
a current backup copy of.

B) Get in the habit of examining unknown  software with HEX/ASCII
utilities that will reveal copyright data, documentation, program
error and prompt messages.   A  good  choice  in  MSDOS is called
PATCH.COM and in CP/M there is DUMPX.COM. Even  if  a  program is
written in protected BASIC, you may still be able  to  find  some
useful data this  way.  [This is also a way to find documentation
within programs without .DOC files or descriptions.]

C) Be wary of text files suggesting  patches  with  DEBUG  or DDT
that you do not understand.  ALWAYS make such modifications to  a
backup copy of your .COM, .EXE, .OVR  files.   There are no known
examples of Trojan horses appearing this way, but...

D) Make those BBS's which  screen  programs  before  making  them
available your first (but not your only) choice for acquiring new
PD software.   If  you  cannot  figure  out  what a program does,
=don't= upload it to some other BBS.

E)  Be wary but not paranoid.  Be  careful but not  overcautious.
Do not fan the fires of hysteria by passing along rumors of worms
and Trojan horses.   Speak  of what you =know=. There are alot of
good public domain programs that will do what you need.  And when
you find it, pass it along.

-end-
