The Risks Digest

The RISKS Digest

Forum on Risks to the Public in Computers and Related Systems

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

Volume 5 Issue 67

Monday, 30 November 1987


o Aging air traffic computer fails again
Rodney Hoffman
Alan Wexelblat
o Computer Virus
Kenneth R. van Wyk via Jeffrey James Bryan Carpenter
o Fiber optic tap
Kenneth R. Jongsma
o A new and possibly risky use for computer chips
John Saponara
o Selling Science [a review]
Peter J. Denning
o Risks to computerised traffic control signs
Peter McMahon
o Risks in Energy Management Systems
o The RISKS Forum is moderated. Contributions should be relevant, sound, in good
o taste, objective, coherent, concise, nonrepetitious. Diversity is welcome.
o Contributions to RISKS@CSL.SRI.COM, Requests to RISKS-Request@CSL.SRI.COM.
o For Vol i issue j, FTP SRI.COM, CD STRIPE:<RISKS>, GET RISKS-i.j.
o Volume summaries for each i in max j: (i,j) = (1,46),(2,57),(3,92),
o Info on RISKS (comp.risks)

Aging air traffic computer fails again

Rodney Hoffman <>
28 Nov 87 11:31:06 PST (Saturday)
In RISKS 4.48 (18 Feb. 87), I related how flights throughout Southern
California were delayed due to the failure of the "9020" air traffic computer
at the L.A. Air Route Traffic Control Center.  Since the 9020 failed 12 times
during the last six months of 1986, this story violates the masthead guidelines
about being nonrepetitious.  However, in the Feb. outage, it was reported that
the 18-year-old system was "expected to be replaced later this year" [1987].

Following Murphy's Law, not only has the replacement not yet happened, but the
system's latest failure was on one of the busiest travel days of the year --
the Wednesday before Thanksgiving, when the passenger load was 40% more than on
a normal weekday.  Additionally, a bomb scare forced an emergency landing of
one plane, further fouling flight schedules.

The computer failure, attributed by the L.A. Times to a "software problem" in
the "massive IBM computer ... that controls high-altitude air traffic for much
of California, Arizona, Nevada, and Utah" lasted 4.5 hours, delayed over 140
flights from Southern California airports for 30 minutes to two hours.  The
L.A. Air Route Traffic Control Center is one of 20 such FAA regional
facilities in the U.S.

Officials stress that the computer failure posed no danger to airline safety.
Instead, it forced controllers to shift to a slower backup computer and "to
carry printed information by hand, limiting the volum of traffic they can
handle."  The news accounts made no mention this time of a date for
installation of a replacement computer system.
                                                  -- Rodney Hoffman

Air traffic computer failure?

Alan Wexelblat <wex@MCC.COM>
Fri, 27 Nov 87 12:21:03 CST

Los Angeles(AP) - A five-hour air traffic control computer failure Wednesday
[the day before Thanksgiving] stalled the holiday weekend getaway for
thousands of Californians.  The computer broke down at about 5:30AM and
wasn't back in operation until about 10:30AM, said a spokesman for the
Federal Aviation Administration.  The computer in Palmdale, 60 miles north
of downtown LA, routes air traffic for Southern California and sections of
Nevada and Arizona.  The cause of the failure was not immediately
determined.  The failure forced controllers to shift to a backup system that
provides less information and the slowed operations, but no safety problems
were encountered, the FAA spokesman said.

--Alan Wexelblat   UUCP: {harvard, gatech, pyramid, &c.}!sally!im4u!milano!wex

    [At San Francisco Airport they were advertising the worst day
    of the year, and delays did propagate...  PGN]

Computer Virus

Jeffrey James Bryan Carpenter <JJC%Vms.Cis.Pittsburgh.Edu@VB.CC.CMU.EDU>
Wed, 25 Nov 87 11:15 EDT
  From: IN%"MD4F@CMUCCVMA"  "User Services List (ADVISE-L)" 23-NOV-1987 09:33
  To:   Jeff Carpenter <>
  Subj: Virus warning!
  Date: Mon, 23 Nov 87 08:05:57 EST
  From: "Kenneth R. van Wyk" <>

  Last week, some of our student consultants discovered a virus program
  that's been spreading rapidly throughout Lehigh University.  I thought
  I'd take a few minutes and warn as many of you as possible about this
  program since it has the chance of spreading much farther than just our
  University.  We have no idea where the virus started, but some users have
  told me that other universities have recently had similar probems.

  The virus: the virus itself is contained in the stack space of COMMAND.COM.
  When a pc is booted from an infected disk, all a user need do to spread
  the virus is to access another disk via TYPE, COPY, DIR, etc.  If the
  other disk contains COMMAND.COM, the virus code is copied to the other
  disk.  Then, a counter is incremented on the parent.  When this counter
  reaches a value of 4, any and every disk in the PC is erased thoroughly.
  The boot tracks are nulled, as are the FAT tables, etc.  All Norton's
  horses couldn't put it back together again...  :-)  This affects both floppy
  and hard disks.  Meanwhile, the four children that were created go on
  to tell four friends, and then they tell four friends, and so on, and so on.

  Detection: while this virus appears to be very well written, the author
  did leave behind a couple footprints.  First, the write date of the changes.  Second, if there's a write protect tab on an
  uninfected disk, you will get a WRITE PROTECT ERROR...  So, boot up from
  a suspected virus'd disk and access a write protected disk - if an
  error comes up, then you're sure.  Note that the length of
  does not get altered.

  I urge anyone who comes in contact with publicly accessible (sp?) disks
  to periodically check their own disks.  Also, exercise safe computing -
  always wear a write protect tab.  :-)

  This is not a joke.  A large percentage of our public site disks has
  been gonged by this virus in the last couple days.

  Kenneth R. van Wyk, User Services Senior Consultant, 
  Lehigh University Computing Center   (215)-758-4988

Fiber optic tap

Sat Nov 28 18:09:48 1987
Up until now, one of the prime advantages of fiber optic cable (aside from its
capacity) has been its perceived resistance to being tapped by unauthorized
parties. The Nov. 16th issue of EE Times had an interesting article that may
change those perceptions.

EE Times reports that Plessey has developed a non-intrusive way of tapping
fiber optic cable. The article states that Plessey's design concept has been
tested with both high-speed digital as well as television signals. They don't
go into details, but do say that the device clamps over an existing cable and
bends it slightly. The small amount of light that is released from the cable
can be detected and amplified.

They do acknowledge the fact that this causes problems for system security, but
feel that the advantages (primarily in making it cheaper to use fiber as a
cable tv medium) outweigh any disadvantages.

I find the implications of this development rather startling.  They don't give
a price for the device, but given that it is intended to be used as a cable tv
line splitter, it can't be out of the reach of any individual.

A new and possibly risky use for computer chips

John Saponara <>
Mon, 30 Nov 87 12:19:28 EST
An interesting use of computer chips was mentioned in "The Christian Science
Monitor" in the November 13, 1987 issue, in an article titled "Showdown takes
shape over plastic weapons":

  Plastic firearms - now being developed for the United States Army by Red Eye
  Arms Inc. - are a bone of contention between antigun organizations and the
  National Rifle Association (NRA).

[The article goes on to tell of the opponents, then continues:]

  "One of the worst nightmares in our fight against terrorism is the
  possibility that airline hijackers could carry plastic guns aboard aircraft
  without detection," says Senator Metzenbaum.  "In order to prevent this
  frightening scenario, we need to act now."

  But David Conover of the NRA says: "Firearms constructed completely out of
  plastic don't exist now."  He argues that a ban on this "future" technology
  does not address the real problem of faulty airport security at the root of
  terrorist activity.

  John Floren, president of Red Eye Arms - which holds the only patent to
  produce such weapons - says the prototype his firm is developing for the
  Army would be entirely plastic but would have computer chips implanted to
  make possible detection of make, model, and serial number from 15 feet away.

[The article goes on to describe the uses of plastic arms and various
legislation concerned with them.]

The idea of adding chips to plastic guns, then selling chip detectors to all
the airport security checkpoints, seems lucrative but does not strike me as the
most sensible approach to the problem.  I have not heard of the use of computer
chips as a detection scheme before.  How foolproof is such a scheme?  If I
stopped sending current to the chip, would the gun then not fire?  Could I
reprogram these chips to have false ID's from other guns, or to not transmit?
Considering the problems the cellular phone companies have had with
reprogrammed phone chips, there seem to be real possibilities of circumventing
such measures.  Does anyone know of any similar detection systems in use at
present, and how secure they are?
                                              Eric Haines

Selling Science [a review]

Peter J. Denning <>
Mon, 30 Nov 87 12:13:26 pst
Many RISKS readers have struggled with the question of generating a rational
public debate when complex technical issues are involved.  What follows is a
review of an interesting little book chock full of insights into how science
journalism works and interacts with the scientific research community.  The
author's comments on treatment of risks in the media are particularly
interesting.  I recommend the book highly.   (pjd)

      Selling Science, Dorothy Nelkin, W. H. Freeman, 1987, 224pp.
                  A review by Peter J. Denning

Have you ever wondered about the apparent contradiction between hyperactive
science journalism and extensive scientific illiteracy?  Between the
promotion of technology as the key to progress in society and the growing
fear of technology?  Between the demand for sophisticated science-based
medicine and the widely supported objections to animal experiments?  Between
the rationality of science and expectations of ``magic bullets'' and
``miracle cures''?  Have you ever wondered whether you will be
misrepresented if you talk to a journalist, whether having your research
discussed in Newsweek is essential to your continued funding, or whether
``popularizers'' like Carl Sagan are advancing science?  If you have, you
are not alone.

These questions touch on fundamental issues in science, technology, and the
press.  Dorothy Nelkin has faced them head on in this fascinating book.
With clarity and painstaking documentation she identifies four main
characteristics of science journalism.  First, most articles are high in
imagery and metaphor, and low in technical content.  Many of the images show
science as arcane, esoteric, beyond normal understanding, authorative,
trustworthy, pure, neutral, and the ultimate source of rationality and basic
truth.  High technology is touted as a quick fix to many problems and is the
source of much disillusionment when it fails.  On debates of great
controversy, such as ozone, artificial sweeteners, or dioxin, or strategic
defense, little technical information is given; instead equal time is given
all ``sides'' no matter how irrational they might be from an objective
standpoint.  Second, much of science is portrayed as a series of dramatic
events, rather than the slow, backtracking, plodding process it really is.
Third, there is a strong emphasis on competition -- e.g., the ``race'' for
breakthroughs, the obsessive 90-hour workweeks of Nobel laureates, or the
``technology war'' between the United States and Japan.  Fourth, scientists
have been actively involved in the press; far from being neutral sources,
they have sought favorable coverage of their projects.  Many institutions
have active media programs that have successfully put the most favorable
information out for public consumption, professional societies have advanced
proposals to control the flow of information to the press, and some journals
by policy refuse to publish any finding that has been ``scooped'' in the
public press.  In the midst of this, scientists have ambivalent attitudes
toward the press, at some times seeking it out, at others criticizing it.

These trends emerge from Nelkin's careful analysis of a large number of
scientifc articles published over many years, and they correlate well with
one's own experience.  But the real contribution of the book lies in its
careful, and highly successful attempt to understand the frames of reference
-- the mindsets -- of scientists and of journalists.  Nelkin accurately
describes the style of scientific research, the norms of objectivity
(especially peer review and reproducibility of results), the professional
ideals, the role of technical jargon, and the rules of evidence widely used
in science -- in short, the unspoken culture in which all scientists
operate.  She similarly describes the culture of journalism, including basic
reporting, editorial contraints, audience assumptions, economic pressures,
avoidance of complexity, and vulnerability to sources.  From this it becomes
easy to appreciate the sources of misunderstandings between scientists and
journalists.  When a scientist says there is no (statistically significant)
evidence of a correlation between power-plant radiation and cancer, a
journalist who knows of a few cases of radiation-induced cancer may ``hear''
a coverup; when a scientist says a new drug produced an improvement in a few
AIDS patients, a journalist may ``hear'' that a cure is imminent.  When a
journalist asks probing questions about risks of technology, a scientist may
``hear'' that the journalist is trying to make the evidence fit his own
hidden agenda; when a journalist omits important methodological details
about an experiment, a scientist may ``hear'' an attempt to oversell a
finding to a gullible public.

Nelkin praises efforts to increase mutual cultural understanding between
scientists and journalists, such as formal science training for science
journalists, the Council for Advancement of Science Writers, and the Media
Resource Service of the Scientists Institute for Public Information.
Although the tension can be softened, she says, the two cultures are
inherently different and the tension cannot be wholly eliminated.
Scientists and journalists will have to come to terms with an uneasy,
occasionally adversarial relationship.

Risks to computerised traffic control signs

Peter McMahon <munnari!!pete@uunet.UU.NET>
Mon, 30 Nov 87 13:07:50 est
Quoted from "Computing Australia", without permission.  [23 Nov 87]

"Computer-run signs over Canterbury Road in Melbourne's eastern suburbs
 suggested a speed of 75 km/h - in a 60 km/h zone - for a clear run through
 traffic lights.

 Despite the anger of police the mix-up was not solved for three days.

 The 26 electronic signs are part of a new information system devised by the
 Road Traffic Authority (RTA)  [...]

 [An obviously upset!] Chief Superintendent Frank Green of the Victorian
 Police traffic department said: "If these mongrel machines are telling
 people to breach the bloody law we'll have to tell the RTA to take its
 computer and shove it."

 RTA and Mach Systems officials denied any bungled programming and said that 
 only two signs were malfunctioning."

Peter McMahon, Computer Science, University of Queensland, Australia

Risks in Energy Management Systems

<Anon @ uk academic establishment>
26 Nov 87 16:07:33 GMT (Thursday)
A while back someone asked about risks in Energy Management Systems; well,
here's one that I know of (even though it isn't related to computer rooms,
unlike the original discussion)....

Some time ago I spent about nine months working for a company which 
produces and sells a computer controlled distributed energy management 
system.  It consists of outstations (which can work stand-alone) and a
central operators station.  The centre was running circa 10000 lines of
uncommented, undocumented spaghetti BASIC which had evolved over a
period of years in the care of a couple of self-taught programmers.  The
outstations contained a few thousand lines of commented but undocumented
assembler.  Communication was by reading & writing of memory in the
outstation using explicit memory addresses embedded in the centre software.

[My job was supposed to be to help them do a complete redesign &
reimplementation, but that was 'temporarily' shelved when the
Managing Director realised what it would cost (amongst other reasons)]

The standard mechanism for fixing a bug involved someone trying to replicate
it, hacking a fix into a copy of the user's version of the program & then
sending it back to them.  No version control, no replication of fixes across
the user base etc.  Testing involved installation on-site & waiting a day or
two to see if things broke.  The only in-house tests were done by running new
software in the outstation that controlled the company HQ : I've seen clients
sitting in our reception area in hat & coats on a Monday morning (waiting to
see someone) because the heating hadn't switched itself on (there was a warm-up
period so manual over-rides at 8am didn't have much effect until after 10) and
as a result in-house tests were strongly discouraged!

Not surprisingly, crashes were common - especially of the 'centre' - which
was embarrassing since the system - originally designed for control of
heating plant in schools & factory complexes (eg one centre for an education
authority, one outstation per school) - was also being used as heating
control for communal housing projects.

However, the worst incident was in fact hardware related.  UK mains voltage
is 240V +/- a maximum percentage.  The outstations contained a transformer
which would drop out (powering down the system) if the voltage dropped more
then a couple of volts below the (supposedly) absolute minimum, it would only
trip in again at nearly 240V (quite a lot of volts above this minimum).  Last
winter was quite severe over here and there was some strain on the electricity
supply system so it ran at near minimum for extended periods (several hours at
a time) with occasional glitches down to the absolute minimum and (we suspect)
sometimes slightly lower.  Now, when an outstation stopped it halted all of the
pumps, boilers etc that it controlled; ie no heating was provided.

Because of the way power was supplied to an outstation in a communal housing
project it was receiving a couple of volts below the actual mains voltage
and one evening it tripped out.  It didn't trip in again until a LOT of hours
later, by which time all of the housing involved had got very cold.  The
accommodation included some sheltered housing for elderly people one of whom
ended up requiring hospital treatment for hypothermia.  Fortunately for the
company nobody sued and the woman involved recovered (remember that hospital
treatment over here is free so there were no medical bills involved).

This sort of problem was far from unique, it's just that the people who are
buying these systems often don't realise the potential dangers and some
manufacturers are so busy trying to grab a share of the market that they
rush bad &/or untested products to the buyers.

Please report problems with the web pages to the maintainer