The RISKS Digest
Volume 14 Issue 83

Monday, 16th August 1993

Forum on Risks to the Public in Computers and Related Systems

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

Please try the URL privacy information feature enabled by clicking the flashlight icon above. This will reveal two icons after each link the body of the digest. The shield takes you to a breakdown of Terms of Service for the site - however only a small number of sites are covered at the moment. The flashlight take you to an analysis of the various trackers etc. that the linked site delivers. Please let the website maintainer know if you find this useful or not. As a RISKS reader, you will probably not be surprised by what is revealed…


Dorney Park Hercules roller coaster injures 14
Steve Walker
About 'Terminal Compression'
Paul Robinson
Ghost in the machine
Mich Kabay
Clusters and electromagnetism
Phil Agre
Brandon S. Allbery
Clipper & French key escrow
Richard Schroeppel
Privacy Digests --- reminder
PDCS2: Predictably Dependable Computing Systems, Open Workshop
Louise Heery
Info on RISKS (comp.risks)

Dorney Park Hercules roller coaster injures 14

"Steve Walker via Peter G. Neumann" <>
Mon, 16 Aug 93 18:48:54 PDT
On July 18 at Maryland's Dorney Park, an occupied train on the Hercules roller
coaster ran into an empty train outside the loading platform, injuring 14
passengers.  The trains operate with no brakes for the 1 minute and 50 second
ride; once they leave the station are free-wheeling when not being towed
uphill.  A faulty sensor was blamed, which was supposed to detect the train
leaving the station, which in turn would enable the computer system to release
the restraints on the empty train so that it could move into the loading area.

Three new safety measures will be added.

* A backup sensor will be added where the first one failed.  (Strangely, the
present sensor is the only one that did not have a backup.)

* The control panel will be modified to display all trains on the track.

* A manual brake will be added.

The temporary fix is to operate only one train on the track.  [From an article
by Chuck Ayers, *The Morning Call*, July 28, 1993, p. B5, sent to RISKS by
Steve Walker.]

This accident sounds remarkably similar to the accident on the Timber Wolf
roller coaster at Worlds of Fun in Kansas City, on March 31, 1990.  The nature
of the accident and the fixes were essentially the same!  See RISKS-9.96.

About 'Terminal Compression'

"Tansin A. Darcos & Company" <0005066432@MCIMAIL.COM>
Sun, 15 Aug 1993 03:29:55 -0400 (EDT)
A company (Inter Pact) has run a number of advertisements on the Internet
regarding their book 'Terminal Compression' which has been subsequently
released in text form which can be downloaded via FTP, with the idea that if
you read it you will send them a shareware donation. I probably would never
have read the book if it hadn't been made available that way.

The copyright slugs on the text indicate publication years of 1991-1993,
seemingly indicating a recently issued book.  (One of the items in the book is
the mention of the new E-Mail address for the White House, which was only
created this year.)

The book has a number of holes in it which I could see through and I decided
to comment.  A shorter version of this message has gone to the Telecom Digest.

The book deals with the combined issues of some of the dangers of
technology and the threats to the privacy of individuals, I have
therefore posted this review to both the Risks List and the Privacy

I will mention one hole which is so obviously inaccurate as to be ridiculous:
A government agency gets a court order telling the newspaper in the story,
"The New York City Times" (note: not 'The New York Times' but the article
makes clear that the paper on Sunday is '34 pounds') to not print any articles
dealing with the ability to read CNG emissions (this is the leakage off a
computer or monitor which can be read like a radio transmitter from a distance
by electronic equipment.)  A reporter writes an article from research, and an
agency gets a prohibition not just against that article - which is a dubious
issue to get a prior restraint order against in the absence of use of
government material, anyway - but that this court order is not to stop a
particular article, but to completely prohibit any articles regarding that
particular *subject*!  I've never heard of a judge that would even consider
issuing that type of order, (an appeals court would tear him to shreds) and
this assumes the paper wouldn't (1) print the article anyway and risk a
contempt citation (2) print a _blank_ article and a copy of the court order.
Apparently this order was never publicized; any time a government agency tries
to suppress publication of something in a newspaper it usually makes
_national_ headlines; the press takes threats to the 1st Amendment *very*
seriously.  CNN's use of the Noriega Tapes comes to mind, and, of course, the
Pentagon Papers and the A-Bomb schematics cases.

Without intending to spoil the story, I wanted to point out that it mentions
only AT&T as the national long distance carrier; a deafening silence exists
about MCI and Sprint.  Yet later in the book it mentions 'FTS-2000' the
private network for government telephone calls that MCI has unsuccessfully
been fighting ever since 1/2 went to AT&T and 1/2 went to Sprint, from the
time of its creation.

At a point in the book, it mentions that the National Security Agency (NSA)
uses its massive computer arrays to monitor - in real time - every telephone
call connection made in the U.S., e.g. every dial call from and to any point
and the call being forwarded, and to where.  This seems to forget that despite
there being some 200+ service points (called LATAs in the trade) in the U.S.
where every call has to go into or out of, not to mention the private cellular
carriers, plus local call forwarding setups and call forwarding through PBXs.
Plus private cellular companies, trunked mobile radiotelephone companies, ham
radio patches...

Even in the book it mentions that one of the calls made by some of the
criminal elements in the book went to 'a Canadian Cellular Exchange'.  I find
it hard to believe that a Canadian telephone company is going to let a U.S.
government agency inquire into its phone system without a court order issued
by a Canadian judge.  Is Pacific Bell going to allow someone from the Canadian
Department of Revenue or Scotland Yard have the list of who owns what
non-listed number without a U.S. Court Order?  I think not.  (I'll skip over
the possibility of bribery for now.)

I find it a bit far fetched to believe that it is possible to put a 'pen
register' on every telephone call made in the United States.  If I call into
General Electric's PBX in New York, or Northrop's in Los Angeles, is a call
transferred out of it (one of perhaps 100 that go out at any minute) mine or
someone else's?

Also, in the story it notes that voice, fax or data transmissions are detected
and that encrypted ones are 'red flagged'.  This is a crock.  Bits are bits;
there is no way to tell based on the bit stream going through a data call
whether the Zmodem Binary transfer I make is a ZIP archive, an EXE file, a
binary data file, a Word Perfect file, or a binary file which has been
processed with PGP or RIPEM.  Bits are Bits; there is no means to
differentiate between a compressed, encrypted transmission (such as a file
processed with PGP) and a binary data file.  It could be possible due to echo
cancellers to tell if someone is using a data transmission device; whether a
fax or modem detection is possible is another thing.  And it also assumes
someone doesn't switch to a non-standard method of data transmission such as
combined voice and data on a compressed transmission channel.  Or local calls
to non-telephone networks such as Compuserve.  Or private long distance
companies that don't use Feature Group service, but simply buy commercial
inward lines in some cities and lease dedicated trunk space.

The virus issues are a little ridiculous too.  Now a couple of years ago a man
named William Harrison, I think, wrote a book called 'virus'.  With the same
basic idea: a series of rogue computer programs can be used to allow someone
to commit crimes.  Harrison's book was much better: I've had more than 12
years of computer experience as well as extensive use of MSDOS and there
wasn't *a single* technical mistake in Harrison's book.

The virus issues are rather silly.  For one thing, unless someone is careless
on large machines, you can't create viruses for VMS or IBM mainframes; they
have fully operational supervisor state protection against runaway programs.
It might be possible to damage some data in some files if you contaminated
them, but in general the kind of virus problems that are reported on PCs
because every program that runs on a PC runs with unlimited privilege.

One of the viruses is mentioned that it fries the printer port and "causes
smoke, then while the user checks that, damages the disk drive".  Now, I know
it's possible on very old Hercules cards to program them wrong and damage
them, and some IDE drive cards have errors in them and miscommanding them
could damage the card or the disk (due to errors in the design.) This one,
however, is a little hard to believe.

I have said it many times: the only reason that viruses can even exist is
because the operating system does not use the memory and task protection
hardware built into every Intel x86 processor higher than the 80186.  A
criminally negligent practice, I would say.  A person I know claims there are
bugs in the 80286 task protection hardware, which I find hard to believe.  In
any case, 80386 hardware contains working task protection capability.  If
viruses became so serious that it was necessary to worry about them, it would
be not too difficult to release the equivalent of the IBM VM/370 operating
system for PCs: at the 80386 level, everything runs in user-mode protection
and does not have of I have said it many times: the only reason that viruses
can even exist is because the operating system does not use the memory
segmentation and task protection hardware built into every Intel x86 processor
higher than the 80186.  A person I know claims there are bugs in the 80286
task protection hardware, which I find hard to believe.  In any case, 80386
hardware contains working task protection capability.  If viruses became so
serious that it was necessary to worry about them, it would be not too
difficult to release the equivalent of the IBM VM/370 operating system for
PCs: at the 80386 level, everything runs in user-mode protection and does not
have kernel privileges.  It can refuse all disk I/O except from the ROM BIOS,
any attempt to access any I/O ports is refused. Without that access - which
requires privilege - a program cannot do damage and can't get access to the
system.  A user could well trust a program and allow it access to the screen
ports.  And the protection program could either allow certain access directly
or trap access and emulate it.  So there would be no means to get access to
the disk drive hardware and no means to attach to other files.  The hardware
doesn't permit access without permission.

If you don't want the story spoiled, do not read this paragraph.  At the end
of the story, a character responsible for some of the problem meets with the
Director of the NSA and we find out that the attacks were intentional with the
knowledge of the NSA Director, to cause the country to increase security on
its computers.  Then, after the director speaks to the person, he has him
arrested.  Now, it's one thing to 'burn' one of your own people, but nobody is
stupid enough to put someone involved with a covert agency in a public trial
where he can - as a legitimate defense - expose an agency's dirty laundry.
The argument of 'National Security' won't wash in a criminal case; if the
defense has evidence that will exonerate it, it is entitled to present it, and
if the government requires it to be suppressed, the court will dismiss the
criminal complaint.  If the man was tried in a secret trial or a military
court where it could be hushed up, that's one thing: but a public trial in
open court in these type of circumstances is hard to believe.

My sister is of the opinion that people don't notice technical errors
in books, movies and TV shows.  I do and I'm certain other people do, too.


Ghost in the machine

"Mich Kabay / JINBU Corp." <>
16 Aug 93 11:53:34 EDT
"Phone malfunction sends out 911 call."
Associated Press: Syracuse, NY.
Globe & Mail / Canada / 14 Aug 93, p. A7 [Summarized by MK]

The owner of a cordless phone was rudely awakened by police after his phone
sent out a 911 call all by itself. AT&T spokesperson Steven Emery
explained that older (> 5 years) cordless phones can accidentally pick up
random frequencies and generate dial tones as a result.  In this case, the
tones happened to be 9, 1 and 1. The emergency response centre recorded the
call and traced the address through the phone company.

Michel E. Kabay, Ph.D., Director of Education, National Computer Security Assn

clusters and electromagnetism

Phil Agre <>
Thu, 10 Jun 1993 17:56:17 -0700
An article by Kenneth R. Foster <> in RISKS-14.70
surveys some literature on clusters of illness that have been associated with
VDT use.  Without wishing to question the author's integrity or methods, it
might be useful to consider the point of view of the people who actually find
themselves becoming statistics in a similar way.  Paul Brodeur's article "The
Cancer at Slater School" in the New Yorker (12.7.92, pages 86-119) is a very
long and detailed account of the travails suffered by a group of elementary
school employees who found themselves dying of cancer at a frightening rate.
They suspected that the high-tension power lines running along the school
playground might have something to do with it, and they called in the power
company to help them investigate.  The story concerns the astonishing lengths
to which the power company, principally through the agency of fully accredited
scientists, went to stonewall, delay, obfuscate, and declare "inconclusive"
the study of these poor people.  Granted that many in the relevant industries
revile Mr. Brodeur, nonetheless if his tale is even faintly representative
of the studies surveyed by Dr. Foster then I despair for the health both of
science and of everyone else.

Phil Agre, UCSD


Brandon S. Allbery <>
Wed, 11 Aug 93 12:28 EDT
>... Such devices would provide high quality cryptographic security
>without preserving the law enforcement access capability that distinguishes
>this cryptographic initiative.  ...

Which, even to a non-crypto expert like myself and given that SKIPJACK is not
the only foreseeable "high quality cryptographic security" algorithm, will
only have the intended effect if all other cryptographic systems are banned;
while you would lose the ability to talk to SKIPJACK-equipped devices, you
could still communicate *without* using SKIPJACK and allow some other device
or software program to perform the encryption/decryption.

Considering the current Congressional review revealing misuse of the NCIC
database (mentioned in the following digest article by Peter Wayner), I see
some other problems as well.  The proposed key escrow system involves
encrypting the escrowed keys in such a way that they can only be decrypted by
LEAF devices, and therefore the escrow agencies will require access to LEAF
devices to examine their own escrowed key lists.  I see two problems with

(1) How are *these* keys encrypted?  If the encryption algorithm is subject
to exhaustive or "shortcut" searches, the keys may as well be in plaintext.
If they are encrypted using SKIPJACK, we have either a chicken-and-egg
situation or a back door to avoid the need to obtain keys from the key escrow
agencies (just feed a LEAF device the conversation *as an encrypted key* and
see what it comes back with).

(2) The only protection against the escrow agency decrypting its escrowed key
list is to keep the agency from obtaining a LEAF device.  I dare say there are
ways around this, such as the one (also mentioned in Wayner's submission) of a
less-than-honest policeman obtaining a LEAF device and "loaning it out".  This
is somewhat mitigated by the fact that the escrowed key is only useful when
combined with the corresponding key from the other escrow agency, but is still
a potential source of problems.

Brandon S. Allbery

Clipper & French key escrow

"Richard Schroeppel" <>
Wed, 11 Aug 1993 11:30:57 MST
Peter Wayner's report on the Clipper system included the bone-jarring sentence:

>                  We know that the government of France is widely suspected
> of using its key escrow system to eavesdrop on US manufacturers in France.

I was under the (obviously naive) impression that the Clipper system was the
first seriously proposed use of key escrow.  Now I discover that France is
using key escrow, right now, today.  The French experience might be relevant
to our own discussion.  Could someone provide more information?

Rich Schroeppel

Privacy Digests

"Peter G. Neumann" <>
Mon, 16 Aug 93 18:49:15 PDT
Periodically I remind you of TWO useful digests related to privacy, both of
which are siphoning off some of the material that would otherwise appear in
RISKS, but which should be read by those of you vitally interested in privacy
problems.  RISKS will continue to carry higher-level discussions in which
risks to privacy are a concern.

* The PRIVACY Forum Digest (PFD) is run by Lauren Weinstein.  He manages it as
  a rather selectively moderated digest, somewhat akin to RISKS; it spans the
  full range of both technological and non-technological privacy-related issues
  (with an emphasis on the former).  For information regarding the PRIVACY
  Forum, please send the exact line:

information privacy

  as the BODY of a message to ""; you will receive
  a response from an automated listserv system.  To submit contributions,
  send to "".

* The Computer PRIVACY Digest (CPD) (formerly the Telecom Privacy digest) is
  run by Dennis G. Rears.  It is gatewayed to the USENET newsgroup
  comp.society.privacy.  It is a relatively open (i.e., less tightly moderated)
  forum, and was established to provide a forum for discussion on the
  effect of technology on privacy.  All too often technology is way ahead of
  the law and society as it presents us with new devices and applications.
  Technology can enhance and detract from privacy.  Submissions should go to and administrative requests to

There is clearly much potential for overlap between the two digests, although
contributions tend not to appear in both places.  If you are very short of time
and can scan only one, you might want to try the former.  If you are interested
in ongoing detailed discussions, try the latter.  Otherwise, it may well be
appropriate for you to read both, depending on the strength of your interests
and time available.

PDCS2 Open Workshop

Louise Heery <>
Mon, 16 Aug 1993 10:17:56 GMT
[Apologies to those of you who have already seen this.]

Please find below the programme for the PDCS2 September Open Workshop,
being held at LAAS-CNRS, Toulouse, 21 - 23 Sept. '93, together with a
registration form. All attendees are subject to the registration fee unless
specifically told otherwise.

Additional information such as hotels and maps of LAAS will be forwarded
upon receipt of completed registration forms, which should be returned to
me NO LATER THAN 10 September '93. However, as individuals are responsible
for making their own hotel reservations, I would advise you to reply sooner
so that I will then be able to send you a list of recommended hotels.
Please also note that the number of places available at the workshop are
limited and that I will, therefore, be working on a first-come-first-served
basis with regard to receipt of registrations.

        Louise Heery

  | PDCS2 Administrative Co-ordinator               |
  | Dept. of Computing Science,                     |
  | Claremont Tower,                                |
  | University of Newcastle upon Tyne, NE1 7RU      |
  | Tel: +44/091-222-7948   Fax: +44/091-222-8232   |
  | E-mail:               |

PDCS2, as its acronym implies, aims to build on, and take significantly
further the work of ESPRIT Basic research Action 3092, Predictably Dependable
Computing Systems (PDCS), on the problems of making the process of designing
and constructing adequately dependable computing systems much more predictable
and cost-effective than at present. In particular it will address the problems
of producing dependable distributed real-time systems and especially those
where the dependability requirements centre on issues of safety and/or
security. The planned programme of research concerns a number of carefully
selected topics in fault prevention, fault tolerance, fault removal and fault
forecasting. The work to be done ranges in nature from theoretical to
experimental; in a number of cases it involves the acquisition or
implementation, in prototype form, of software tools, and their experimental


Tuesday 21 Sept.
Welcome: Alain Costes (10 mins)
Introduction: Brian Randell (50 mins)
Moderator: Alan Burns (University of York, York, UK).
Speakers: (1) Johannes Reisinger, "Real-time Interprocess Communications in
MARS" (Technische Universitat, Vienna, Austria);
(2) Andrea Bondavalli, "Adaptable Fault Tolerance for Real-Time Systems"
(CNR, Pisa, Italy).
Moderator: Lorenzo Strigini (CNR, Pisa, Italy).
Speakers: (1) Jean-Charles Fabre, "Fault and Intrusion Tolerance in
Object-oriented Applications by Fragmentation-Redundancy-Scattering" (
LAAS-CNRS, Toulouse, France in conjunction with University of Newcastle,
(2) Robert Stroud, "Object-oriented Techniques for Realising Fault
Tolerance in Software" (University of Newcastle upon Tyne, Newcastle upon
Tyne, UK).
Room 1  Room 2  Room 3
Demo A  Demo C  Demo D
Demo B  Demo C  Demo D

Wednesday 22 Sept.
Moderator: Alain Costes
Speakers: (a) Marc Guillemont (Chorus Systemes)
(b) Malcolm Mills (Software Sciences Limited)
(c) Peter Knezu (ALCATEL Austria)
Moderator: Yves Deswarte ( LAAS-CNRS, Toulouse, France).
Speakers: (1) Bev Littlewood & Tomas Olovsson, "A Pilot Experiment in the
Modelling of Operational Security" (CSR, City University, London, UK and
Chalmers University of Technology, Goteborg, Sweden);
(2) John McDermid, "Developing Secure Systems in a Modular Way" (University
of York, York, UK).
Moderator: Hermann Kopetz
Speakers: (1) Eric Jenn, "Fault-injection into VHDL Models: The MEFISTO
Tool" (LAAS-CNRS, Toulouse/Chalmers University of Technology, Goteborg);
(2) Johan Karlsson, "Validation of the MARS System by Physical Fault
Injection," (Chalmers University of Technology, Goteborg).
Room 1  Room 2  Room 3
Demo A  Demo B  Demo C
Demo A  Demo B  Demo D

Thursday 23 Sept.
Moderator: Tom Anderson (University of Newcastle upon Tyne, Newcastle
upon Tyne, UK)
Speakers: (1) Pascale Thevenod, "Functional Testing of Critical Software:
Formal and Statistical Approaches; A Case Study" (LAAS-CNRS, Toulouse and
LRI-Universite de Paris-Sud, France);
(2) Werner Schuetz, "A Statistical Approach for Testing the Execution Time
of Program Units" (LAAS-CNRS, Toulouse, France and Technische Universitat,
Vienna, Austria).
Moderator: Karama Kanoun (LAAS-CNRS, Toulouse, France).
Speakers: (1) Mohamed Kaaniche, "Discrete-time Software Reliability
Modelling and Evaluation" (LAAS-CNRS, Toulouse, France);
(2) Sarah Brocklehurst & David Wright,"General Methods for the Improvement
of Software Reliability Predictions" (City University, London, UK).
Moderator: Jean-Claude Laprie
Speakers: (a) Jack Stankovic (University of Massachusetts)
(b) John Meyer (University of Michigan)
Closing Address: Jean-Claude Laprie (20 mins)

A> "Object Oriented Fragmentation/Redundancy/Scattering" (University of
Newcastle upon Tyne, Newcastle upon Tyne, UK and (LAAS-CNRS, Toulouse,

A distributed Electronic Diary system which has been designed using Eiffel
design tools and implemented on top of the DELTA-4 Support Environment will
be demonstrated. The system uses fragmentation-redundancy-scattering to
provide means of achieving high reliability and security by tolerating both
accidental faults and intentional intrusions.

B> R. Schlatterbeck, "Tool Integration by CDL" (Technische Universitat,
Vienna, Austria);

In the first phase we will explain the purpose, the structure and the
operation of CDL using a set of pictures. In the second phase we will
demonstrate the prototype implementation of our CDL tools.

C> "Analysis of Predictive Accuracy and Recalibration of Reliability Growth
Predictions" (City University, London, UK);

Some real software failure data will be analysed using reliability growth
models, an analysis of the accuracy of the resulting reliability
predictions, and their recalibration, will be conducted.

D.G. Leber, "Single Board Computer with High Error Coverage" (Technische
Universitat, Vienna, Austria);

Presentation of a single board computer with high error detection coverage:
We will explain the special mechanisms within the hardware and the
operating system of the new MARS nodes which are responsible for realizing
both the fail-silence property and a predictable timing behaviour

Fee 1800 FF (inclusive of VAT)

Last Name:___________________________________________

First Name:__________________________________________

Title: Prof/Dr/Mr/Ms/Mrs/Miss/Other:_________________




Tel:________________    Fax:________________    E-mail:___________________

Delete as applicable:
Please reserve a place for me at the Open Workshop      YES/NO
Date of arrival:____/09/93

Please add my name to the PDCS2 Technical Report mailing list   YES/NO

I will attend the banquet dinner: Yes/No
I am vegetarian: Yes/No

Please indicate preferred method of payment (delete all methods EXCEPT the
method of payment chosen):
Fee 1800 FF (inclusive of VAT)

Bank Transfer:
(I will send out the details necessary for this upon receipt of
French Bank cheque to the order of ADERMIP
Order form for invoice
Credit Card: Visa/Mastercard/ EuroCard
On site payment by cash/credit card

Return form, to arrive no later than 10 September 1993, to: Louise Heery,
PDCS2 Administrative Co-ordinator, Department of Computing Science,
University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK.
Fax: +44/091-222-8232; e-mail:

Please report problems with the web pages to the maintainer