The RISKS Digest
Volume 5 Issue 80

Monday, 21st December 1987

Forum on Risks to the Public in Computers and Related Systems

ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

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o Re: IBM Christmas Virus
Ross Patterson
o Logic Bomb case thrown out of court
Geoff Lane
o Repository for Illicit Code
Steve Jong
o Roger Boisjoly and Ethical Behavior
Stuart Freedman
o Truncation and VM passwords
Joe Morris
o Competing ATM networks
Chris Koenigsberg
o Info on RISKS (comp.risks)

Re: IBM Christmas Virus

Ross Patterson <A024012%RUTVM1.BITNET@CUNYVM.CUNY.EDU>
Mon, 21 Dec 87 15:22:26 EST
    There  have  been  several  messages to  RISKS  lately  about  the
CHRISTMAs EXEC virus  on IBM's network.  This was an  extension of the
same problem  on BITNET and  its European counterpart, EARN.   Since I
raised the general alarm about it, I'd like to answer a few questions.

    The virus used two standard CMS files, called NAMES and NETLOG, to
help it infect other users.  The NAMES file contains a list of userids
and system names that you  correspond with frequently, allowing you to
abbreviate them  to a mnemonic  nickname when sending mail,  files, or
interactive messages.   I composed  this mail  by sending  to "RISKS",
which my NAMES file lists as user RISKS on system KL.SRI.COM.  You can
also list  phone numbers, paper  addresses, etc.  There is  a commonly
available program that  will print off a personal  phonebook from your
NAMES file ("Traveling  Sidekick" from the days BB  - Before Borland).
The  NETLOG file  lists all  users you've  sent mail  or files  to, or
received them from.   It's a very nice audit trail  when you're trying
to remember where you got that copy of Space Wars.

    After  typing  the Christmas  Tree  on  your terminal,  the  virus
proceeded to  read both  the NAMES and  NETLOG files to  get a  set of
target addresses.  It then sent a copy  of itself to each of them, and
finally deleted itself.

>From: (Dave Curry)
>Subject: IBM invaded by a Christmas virus {RISKS 5.72}
> ...
>This article seems to have a lot of things in it that the reporter didn't
>understand.  I assume that the "terminals" in question are really PC's
>connected to the mainframes; for one thing.

    The terminals  mentioned are generally  IBM 3270's, and  PC's with
IRMA-type cards.  The virus ran on the host system, not on the PC.

>                                             Plus, I presume the "Don't
>browse it" refers to the VM/CMS "BROWSE" command used for looking through
>files, and not just to the regular English word.

    Both, actually.  The intent was  obviously to stop the reader from
going  further down  into  the file,  where the  real  purpose of  the
program was quite obvious.  The  language used (IBM's REXX) is usually
interpreted,  so the  program was  sent  in source  form.  Anyone  who
bothered to read below the second screen-full (like all of us paranoid
Systems  Programmers)  began to  see  the  trouble.  It  was  slightly
cloudy, as all the variable names  were in German, but seeing was fair
to good.

>Subject: IBM Xmas Prank {RISKS 5.79}
>From: Fred Baube <>
> ...
>"The culprit is unknown

    That is  no longer the case.   The culprit has been  tracked down,
and barred from  access to his/her system.  A note  to that effect was
broadcast to  a number of  mailing lists  by the General  Secretary of
EARN.  The source system had recently been attached to the West German
section of EARN, and the user who started it all only intended to send
a greeting  to a  few friends.   To quote a  TV commerical,  "...  and
they'll tell two friends, and so on, and so on, ...".

>                        .. but preliminary investigation suggests
>that the message originated outside the company.  IBM's mail
>system is attached to those of several other institutions."

    Quite so.  No  one seems quite sure which of  the gateways between
BITNET/EARN and IBM's internal network, VNET, passed the first copy of
the  virus.   It  matters  very   little,  since  it  found  the  VNET
environment  even more  conducive  to  reproduction than  BITNET/EARN.
VNET'ers apparently keep much larger  NAMES files than BITNET'ers.  It
wasn't long before  the links were carrying more  CHRISTMA EXEC's than
anything else.

>"From start to finish, the message survived only hours .."

    Per copy, perhaps.   The first known instance of  infection was at
about  1300  GMT on  Wednesday,  December  9.  Within BITNET,  it  was
generally stamped out by the  following Monday, December 14.  On VNET,
it  didn't show  up until  a day  later, and  was mostly  killed in  a
massive network shutdown on Friday.

>(1) An incoming message can contain an executable program,
>    that can easily be run ?

    Yes.  Please  remember that the  Internet is not the  only network
style in the world.  In BITNET and  VNET, mail is just another case of
file  transfer.  File  transfer is  performed by  the sender,  not the
receiver.   These are  store-and-forward  networks, so  the path  from
system  A to  system B  need not  be intact  for the  duration of  the
transfer.  The viral program was transferred  as a normal file, not as

>(2) Such a message can be remailed under its contained program's
>    control, presumably with the name of the last victim in the
>    "From:" field ?

    It wasn't  mailed.  Thus, there  wasn't any From: field,  etc.  It
did carry  the system name and  userid of the most  recent victim, but
not any trace-back information.

>(3) Can IBM trace it to an originator, or was anonymity possible ?

    A task force of BITNET and EARN systems programmers traced it back
to its source, by the usual disease-control procedures:

   Doctor: "Miss  X, you've got a  nasty case of viral  <Y>.  Who have
            you had  contact with recently?".

   Miss X: "Just a moment, I'll check my notebook."

    A byproduct of the tool used to  transmit the virus is an entry in
the NETLOG  file listing the userid  and system name of  anyone it was
sent to, making it easier than usual  for Miss X to remember.  In some
cases, the  user had suppressed the  NETLOG facility, but that  is the
exception, not the rule.

>(4) How/where can readers of RISKS submit something similar ?
>    (strictly for professional testing purposes)

    Noplace safely.  Please  don't try it on anything  but an isolated
network, and then coldstart your spool afterwards.

>(5) Is the Internet similarly vulnerable ?

    Not to  this one.  It  plays on  several things that  the Internet
doesn't have:

   1) A  large number of IBM  VM/CMS systems.  The program  would only
      run in a CMS environment.  There is no reason one couldn't write
      something similar in any other language, though.

   2) A  suitable file transfer  system.  FTP doesn't apply.   It must
      provide a  way for a user  to receive an unsolicited  file, in a
      runnable form.

   3) A good method of determining  targets.  The CMS NAMES and NETLOG
      files provided an excellent source of information.  I suppose in
      a Unix environment, ".alias" and "/etc/aliases" would be ok, but
      .alias  is  comparatively rare,  while  NAMES  files are  almost
      universal in CMS.

>The prank seems to be benign, and therefore beneficial.

    That is being debated in several  circles.  I, for one, agree with

>IBM seems to have dealt with it effectively (or have they ?).

    Yes, they have.

>Browsing this message is no fun at all.  Just type Christmas ..

    The lesson of  this one is the  same as for PC  viruses: Never run
something you don't recognize.  When the virus first appeared, several
people suggested that  it was the work of students,  and that it might
be used negatively in an ongoing argument over whether students belong
on BITNET.   When we heard  that "professionals" inside IBM  were also
running  programs they  didn't recognize,  that particular  suggestion

    This virus  was quite  sly, in  that by  sending itself  to people
listed in  your NAMES and  NETLOG files, those people  would recognize
the source (you) as a friend, and be generally less inquisitive, until
things  got  nasty.   Lesson  #2: Even  your  friends  sometimes  make
                                    Ross Patterson, Rutgers University

    [RISKS received an unusually large number of messages on this subject --
    from Fred Baube, John Owens (2), Allan Pratt, Anne Louise Gockel, and 
    Bruce O'Neel.  I started trying to edit them down, but rapidly gave
    up that strategy — inordinate overlap.  So, I will take a new tack,
    which is to put out Ross' message — which was the most comprehensive --
    and then give Fred, John, Allan, Anne and Bruce first priority if THEY
    wish to comment marginally or additionally thereupon.  Please be terse
    — and avoid replicating ALL of the foregoing text in your messages,
    as some of you have been doing.  (One of the joys of mailers?)  PGN]

Logic Bomb case thrown out of court

<"ZZASSGL" <ZZASSGL@CMS.UMRCC.AC.UK> [Presumably Geoff Lane]>
Mon, 21 Dec 87 16:03:05 GMT
As I have not seen anything about this in RISKs yet ...  The case brought
against James McMahon, who was accused of placing logic bombs within the
computer system used by Pandair Freight, has been thrown out of court because
of "unsatisfactory evidence". The judge has ruled that there was no case to
answer.  This was reported in Computer Weekly dated December 17/24, 1987.

It will be interesting to learn in what way the evidence was unsatisfactory.
There used to be a problem in British law(and it may still exist) in that
evidence could only be given by humans.  Information generated by a computer
without the explicit involvement of a human could not be used in court.  I
may have got this legal point garbled as I don't speak legalese.

Geoff, UMRCC

Repository for Illicit Code

Steve Jong/NaC Pubs <>
21 Dec 87 16:23
If there is a legitimate need to study illicit code such as viruses and
embezzlement routines, and not just a forensic need to try and track down
the author, then there could indeed by a need for a repository.  I suggest
the model of the Center for Disease Control in Atlanta, which has samples of
pathogens.  However, note that there was (is?) a controversy surrounding
CDC's wish to keep samples of smallpox, which, it is believed, has otherwise
been eradicated from the face of the earth.  Why leave one known source?

Personally, I'd just as soon not have the code samples around.  I'd just be
tempted to play with them.  (Disclaimer: I'm not a programmer.)

   [Program viruses, Trojan horses, etc., will never be competely eradicated.  
   They tend to re-erupt spontaneously or be rediscovered.  PGN]

Roger Boisjoly and Ethical Behavior

Mon, 21 Dec 87 13:20:18 EST
To add my $0.02 to the conversation on Roger Boisjoly, I agree with Ronni
Rosenberg, having seen a videotape of him telling his story.  I seem to recall
that he made reference to the same period of silence (the last time anyone
called for objections to the launch) that Henry Spencer did.  Boisjoly said
that he was much too astonished at the decision to go through with the
launch (despite his strong objections) to say anything at that point.  He
did not fully recover his senses until after the teleconference ended.  I
think that we can only expect the man to be human; we can't always act
heroically when we're in shock...

Stuart Freedman or rti!xyzzy!
Data General Corp.(Mail Stop E-219), Westboro, MA 01580 +1(617)870-9659
Pick an e-mail address — any e-mail address...

Truncation and VM passwords <Joe Morris>
Mon, 21 Dec 87 10:24:46 EST
In RISKS 5:79 Alex Heatley reports that he can establish a password of more
than eight characters in the IBM VM system, but that on login the system
truncates the entered password to eight characters, then (correctly) reports
that it fails to match the one in the access control file.

I don't know what security system his system uses, but IBM's DIRMAINT product,
which is probably the most widely used directory maintenance facility used
in VM installations, refuses to accept an oversized password.  I just tried
to enter one on our system, and was rebuffed with message DVHDIR017E.

Joe Morris (jcmorris@mitre.ARPA)

competing ATM networks

Chris Koenigsberg <>
Sun, 20 Dec 87 22:22:24 -0500 (EST)
The two competing local ATM cards in Pennsylvania are Cashstream and MAC. All 
the Pittsburgh banks with ATM cards are signed up for one or the other local 
networks. Cashstream is run mainly by Mellon Bank, MAC mainly by Pgh. National 
Bank. Both Cashstream and MAC extend into neighboring states. Meanwhile 
Cashstream is hooked up with the national ATM network called CIRRUS, while MAC 
is part of the national PLUS system.

I've used my Cashstream card in CIRRUS machines in other faraway states, and 
I've used my MAC card in PLUS machines across the country. But I always 
assumed that these two kinds of cards were big competitors at each level : 
bank vs. bank, local net vs. local net, and national vs. national, and that 
the two sides wouldn't cross.

But in New York, there are ATM machines which accept both MAC and Cirrus 
cards. I was surprised, since in Pennsylvania, MAC cards work in PLUS machines 
but not in Cirrus machines, as MAC's local competitor Cashstream is connected 
with Cirrus.

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