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 14 Issue 01

Weds 04 November 1992


o Tandem Clock Outage
J. Lyngved via Paul Hicks and Bruce Baker
o Re: Air Inter A320 descent
Pete Mellor
o Re: Leaving greasy marks on monitors may be dangerous
Pete Mellor
o Re: Risks of Cellular Speech
Phil Karn
Dave King
o Re: Cash dispenser fraud
Pete Mellor
o Re: Caller-ID and Modems
A. Padgett Peterson
o Re: Symantec/Borland [and Brazilian President]
Rob Horn
o Re: Interesting/obscure interaction between users
Jerry Leichter
o Re: 15th NCSC - eavesdropping
Brinton Cooper
Carl Ellison
o Re: New risk reports
Pete Mellor
o ASEE '93 EPPD Call for Papers
Ken Sollows
o Info on RISKS (comp.risks)

Tandem Clock Outage (collated from various sources)

"Bruce Baker" <>
3 Nov 1992 15:27:25 -0800
   [Bruce sent me a stack of messages.  This (slightly edited) is the most
   coherent, from J. Lyngved and forwarded via Paul Hicks of RPS Ltd.  PGN]

FROM: Lyngved.J

In case you have not yet heard, our TANDEM stopped last night.  So did almost
all TANDEMS around the world, I've heard.

We are currently trying to get it running again, helped by TANDEM people.

Worse yet, they inform us that unless we do some upgrading it will stop again
on January 7, 1993.

This is not an April [fool's] joke.


    [I hope the details surface in RISKS.  It appears that at 15:00 on the 1st,
    all Tandem CLX machines abended, causing the BASE24 Nucleus to dump with a
    Trap 2 (arithmetic overflow) in the procedure age-timers.  A cold reload
    would get the system going again.  Stay tuned (or detuned).  PGN]

Re: Air Inter A320 descent

Pete Mellor <>
Tue, 3 Nov 92 21:48:50 GMT
It just *so* happened that I was in France last week (on something completely
unrelated: an ISO meeting). I dropped into the office of a certain lawyer in
Paris on my way out and back.

On the way out, he gave me a photocopy of an article in "Le Canard Echaine",
about Michel Asseline's book about the Habsheim crash. On the way back, he
gave me two photocopies of articles in "L'Alsace" (regional newspaper serving
Habsheim and surroundings), and "Le Monde", which had appeared that very day
(Friday 30th Oct.) or the day before.

The last two articles are detailed accounts of the "descente intempestive"
which has been reported recently. If what the articles say is true, then it
looks as though all bets are off regarding Bangalore, Strasbourg, AND the
A300 and A310 crashes in Kathmandu.

To summarise: When "rate of descent" mode is selected, (as opposed to "flight
path angle"), a fault in the FMGS software occasionally causes the aircraft to
descend at **2 or 3 times** the rate selected by the pilots.

They don't even NEED to confuse "rate of descent" and "flight path angle"!!!

This was reported by several crews who were able to recover the situation
because they weren't flying over mountains at the time.

The FMGS software (I *think*) is NOT regarded as SAFETY-CRITICAL!!!!

If this is so, then it is NOT certified to RTCA/DO-178A level 1.

The SAME FMGS is in use on A300, A310, and A320 (at least, *basically* the

The French pilots' unions are up in arms about it, and in France generally,
all hell seems to be breaking loose.

Typically, in the UK press, the silence is deafening. (Presumably none of
their French correspondents can speak French! :-)

The other thing that my French lawyer colleague gave me was a signed copy of
Michel Asseline's book about Habsheim: "Le Pilote - Est-il Coupable?"
(You've guessed! He's Asseline's solicitor! :-)

Since I read French even more agonisingly slowly than I read English, you'll
have to wait a while for my detailed review. In the meantime, I will try to
find time in the next few days to translate the three newspaper articles.

If anyone sees anything in the media (French, UK, US and all points between),
let us all know.


PS: If anyone knows of a publisher willing to handle the forthcoming English
translation of Asseline's book, let me know about that, too.

Peter Mellor, Centre for Software Reliability, City University, Northampton
Sq., London EC1V 0HB, Tel: +44(0)71-477-8422, JANET:

Re: Leaving greasy marks on monitors may be dangerous (RISKS-13.89)

Pete Mellor <>
Tue, 3 Nov 92 20:27:00 GMT
> Apparently, so I am told, CFCs have been replaced in these aerosols by
> flammable propellants.

Come back CFCs, all is forgiven!

Actually, I suspect that most of the CFCs that hit the ozone layer come from
decommissioned refrigerators or industrial waste, and not from you or I
spraying our hair or computer screens. (Prince Charles is reported to have
banned the use of CFC aerosols in the Palace. "Every little helps!", as the
wren said when she pee'd in the ocean! :-)

Why not go for the "Pump and Spray" approach adopted by a certain manufacturer
of hair laquer? The lid of the can activates a pump. You push it up and down a
few times to pressurise the can, and then spray out the contents with a
propellant no more polluting (or inflammable) than compressed air.

Peter Mellor, Centre for Software Reliability, City University, Northampton
Sq., London EC1V 0HB, Tel: +44(0)71-477-8422, JANET:

Re: Risks of Cellular Speech (RISKS-13.89)

Phil Karn <>
Tue, 3 Nov 1992 02:29:38 GMT
> In a three-month study of the Metro Toronto area earlier this summer, Bell
> found that 80 percent of all cellular telephone traffic is monitored by third
> parties.  Even more eye-opening is the fact that 60 percent of monitored calls
> are taped for closer scrutiny and culling of marketable information.

I would very much like know how Bell Canada obtained these figures, given that
the monitoring of cellular telephone calls from the privacy of one's home is
essentially undetectable.

> After discussing privacy laws, legalities, and realities, Flinn notes that at
> Scanners Unlimited in San Carlos, CA, "about a quarter of the customers are
> interested in telephone eavesdropping."

This problem will soon be stopped cold, as Congress recently passed a law to
outlaw the manufacture of scanners capable of receiving cellular telephone
calls. A truly inspired solution to the problem, comparable to the "B-Ark"
people in "The Hitchhiker's Guide to the Galaxy" burning down the forests to
solve the inflation problem caused by making leaves legal tender.

Risks Of Cellular Speech

Dave King <>
03 Nov 92 16:47:58 EST
I must apologize to the list.  I have been informed that we cannot confirm the
percentage figures that were mentioned in the note that I quoted in the item
that I posted yesterday concerning a study of the monitoring of cellular
traffic in Toronto, Canada.

David L. King, IBM Southeast Region I&TSS, Mail Drop D072, 10401 Fernwood Road
Bethesda, Maryland 20817, (301) 571-4349

Re: Cash dispenser fraud (RISKS-13.89)

Pete Mellor <>
Tue, 3 Nov 92 20:39:33 GMT
Erling Kristiansen writes (concerning cash dispenser fraud):

>  If you do not take your money within a given time, the machine will swallow
> it back, and undo the transaction on your account.

Not in my experience. (See RISKS about a year ago.) I simply forgot to take the
money, and the machine swallowed it. To get the amount credited to my account,
I had to 'phone the bank personally, and the amount was only repaid after the
till had been (manually) balanced, and the excess cash in stock verified.

Peter Mellor, Centre for Software Reliability, City University, Northampton
Sq., London EC1V 0HB, Tel: +44(0)71-477-8422, JANET:

Re: Caller-ID and Modems (Slade, RISKS-14.01)

A. Padgett Peterson <>
Tue, 3 Nov 92 10:33:50 -0500
I realize that this may be a bit out of the ordinary for a RISKS posting but
since Rob Slade raised the issue in RISKS yesterday, I have gotten quite a few

First, it is my belief that much of the RISKS of dial-up access points is
increased by the ease of discovering such points. War Dialer and Exchange
Hacker programs are plentiful and have contributed to a number of notorious
cases recently (the MOD is said to have used this method of discovering such

The problem is that with all current systems that I am aware of, it is first
necessary for the modem to answer the telephone before any authentication can
take place. By doing so, the line may be positively identified as having a
modem even if call-back or other rigorous identification means are in use.
Once such line have been identified, serious penetration attempts can take

When announced, it was realized that Caller-ID provided an answer to this
dilemma that was much better than the "ATS0=7" which I previously advised.
(This command instructs a modem responding to the "AT" command set not to
answer the phone until the seventh ring - typically about 40 seconds after
connection starts. Since most War Diallers allocate only 30 seconds to each
number, this is an effective, if annoying, answer).

Caller-ID places a 1200 baud digital signal on the telephone line between
the first and second ring signal. The important factor is that the phone
does not have to be answered to received this information. Some modems
are able to pick up this signal and present it to the host computer.

What I did last weekend was to create a PROCOMM PLUS script file using their
ASPECT language to do the following:

1) When the telephone rings the calling number is captured.

2) The number is recorded into a "LOG" file and then a scan of a database
   of "approved" numbers (flat ASCII) is done.

3a)If the number is found in the "approved" file, PROCOMM is instructed to
   enter its "HOST" mode - an effective single line BBS emulation that
   supports uploads/downloads/mail/and "chat" and the phone is answered.


3b)If the number is not found, the line is not answered

4) After the caller hangs up, the system resets.

Given this, even if the "bad guys" know the number, they will still have to
find a way to induce the modem to answer the line. Certainly if this were in
widespread use, much of the plot of "Sneakers" would have had to be re-written.

Yes, I know that there are problems, particularly with "roving" people. If
however 80-90% of all access could be handled in this manner (e.g. for
telecommuters), the balance could use extraordinary means.

Right now the capability is limited to a PC running PROCOMM Plus 2.01
and equipped with a Supra Corp. SupraFAXmodem having the Caller-ID
ROM upgrade. I haven't tried any others.

Why did I choose this combination ? - because I had them (both were privately
purchased) and they would do what was necessary - this is all a hobby
to me. In theory any Caller-ID unit with an RS-232 output could be used
as could any scripting BBS software. What was desired was a "proof-of-
principle" not a commercial product.

The PRIVACY concern is easily handled: you can block your number from
Caller-ID (star-6-7 in most places) but I reserve the right not to have
my computer answer the phone if you do.

IMHO this capability is still in its infancy but is important and easily
implemented, we are just seeing the tip of the iceberg now.

Right now the biggest drawback is the limited availability of Caller-ID
though IMHO again it will be nationwide in two years (law enforcement
agencies already have a wider coverage so the holdup is political, not

RISKS ? To me the most important is the question "Could an individual
use star-6-7 to block the telco's ID and send their own 'approved'
1200 baud stream ?" The consensus so far is "NO" and I have some friends
at GTE experimenting.

In any event, the script is FreeWare for anyone who might be interested,
just be aware that I do not have any distribution means (might be able to
send as E-Mail) and negative free time.

The importantance of this is that it is no longer theory, it is now fact, CHEAP
        Padgett                         <>

ps: Just to avoid the inevitable, Supra Corp. can be reached in Oregon
    at (800)727-8647 (do not think Caller-ID is available outside the US
    yet). I bought mine from a mail-order house for about 3/4 list price.
    PROCOMM is a product of Datastorm Inc. (800)326-4999 (plugs)

Re: Privacy of e-mail (Symantec/Borland suit)

Tue, 27 Oct 1992 08:08 EST
For further commentary on this issue, see the recent Forbes magazine article by
Mitch Kapor.  It raises the issues of how the ECPA Act and similar California
privacy legislation might apply to this case.  It will probably make a number
of lawyers rich and drag on for years, but there are some very complex legal
issues involved.  The issue involves MCI's responsibility as an e-mail provider
under ECPA and whether Borland was or was not authorized to have access to
Wang's mail.  I doubt that all the relevant facts are yet public.

Rob Horn

Symantec/Borland and Brazilian President

Sun, 1 Nov 92 15:19 PST
There are two topics in RISKS-13.87 that are actually related.  Someone asked
about software that could have been used to get the deleted files from the
Brazilian president's disks.  There was also a mention of the Symantec/Borland
suit over theft of trade secrets.  The Wall Street Journal had the most
complete article about the latter (I don't have the date handy) and mentioned
that Borland used a copy of a Symantec product, Norton Utilities, to recover
erased files that are being used as evidence in the case against Symantec.
Apparently Norton Utilities is widely used by law enforcement agencies for
gathering evidence in cases involving PCs.  The product also includes a utility
for ensuring that deleted data cannot be recovered, but many people seem to
think that if they "delete" a file and it seems to be gone, then that's what
really happened to it.  There's always a risk when a user's model of what the
computer is doing behind the scenes is a simplified one which is adequate for
doing their work, but not for predicting the outcome of unusual circumstances.

re: Interesting/obscure interaction between users (Honig, RISKS-13.88)

Jerry Leichter <>
Sat, 31 Oct 92 13:51:06 EDT
David Honig remarks on his discovery that users of SunOS can allocate shared
memory resources and fail to delete them properly, thus effectively rendering
them unavailable to later programs, which fail.  Only a reboot will resolve the

A couple of remarks:

    a)  All the Unix System V IPC objects have this property.  Allocating
        and failing to free shared memory segments, semaphores, or
        message queues, all of which exist in limited numbers and
        cannot be replenished, can also cause later numbers to fail.

        Mr. Honig remarks that there are typically 100 memory
        segments.  There are typically considerably fewer semaphores
        or message queues.

    b)  This is not a SunOS problem; it's inherent in System V, which
        defines a set of IPC facilities which allow objects to persist
        even though no one is using them.  Programs probably exist
        which rely on this, so I doubt it can be changed.

    c)  It IS possible to recover from this without rebooting, since root
        can attach to the "lost" objects and delete them.  Of course,
        you have to find them first.  At least on Ultrix, and probably
        on most other systems, there is a program (ipcstat, I think)
        which displays a list of all IPC objects in the system.  It
        would remain up to a human being to decide which ones can
        be deleted safely, however.

    d)  Given (c), the situation is, in a way, analogous to running out
        of disk space because the disk is full of old junk.  This
        similarity, however, is tenuous, for several reasons:  Disks
        are much larger than the sets of IPC resources available;
        the names of files being created are generally known, except
        for temporary files - which as a matter of policy are treated
        as expendable after a short time, and automatically cleaned
        up; and people regularly see directory lists, but they rarely
        if ever have reason to run ipcstat.
                            -- Jerry

Re: 15th NCSC (Denning, RISKS-13.87)

Brinton Cooper <abc@BRL.MIL>
Mon, 2 Nov 92 23:38:32 EST
First, I should hate to think that my right to safety from illegal search and
seizure and/or illegal eavesdropping on my telephone conversations rested on
the good will and integrity of a phone company!

Second, it's difficult to envision a non-governmental agency, created by the
government but not really government.  The Post Office purports to be a
non-governmental agency but isn't.  It's employees still look and act like US
Civil Servants, and the P.O. can easily conduct a "mail cover" for a
governmental agency without a court order.

You must remember that court orders, search warrants, and the like are useful
only when the information or evidence gathered under their aegis is to be used
in court against a suspect.  If information is being gathered for political
purposes, to blackmail someone, or to subvert the law (Watergate, Iran-Contra,
the Italian bank, etc), the information will never see a public forum.  Thus,
the constraints of court orders are obviated.

The FBI needs to fund its own R&D out of its budgetary resources, just as the
rest of the government at all levels must do.  There is talent that can "red
team" modern telecommunications and find trapdoors when necessary.

You must never forget that the gravest threat to our freedom is, and always has
been, government itself.
                                             _Brinton Cooper

Re: Key registration (Denning)

Carl Ellison <>
30 Oct 92 21:42:12 GMT
In the exchange over Dr. Denning's proposed key registration agency, I have
learned that there are civilized countries out there (eg., Finland) where it is
illegal for the government to do a wiretap.  Even getting phone records in
Finland (for traffic analysis) apparently results in the target's being told.

Sadly, we're not that civilized, it seems.

I can imagine some large company (one of the Baby Bells, perhaps) making a line
of scrambled, digital phones -- perhaps cellular -- perhaps just wireless, but
with digitization and end-to-end encryption done in the handset.  I could see
this line of phones using RSA (1000 bit) to pass triple-DES keys around (DES
with 3x56 bit keys and 3x64 bits of random IV for CBC mode).

I can imagine that large company offering to register keys for the FBI --
just to keep from being hassled by the Gov't.

Were that to happen, I might even buy such a phone -- knowing that it's
insecure but also knowing that my neighbor won't be listening in on her
wireless phone.

However, it's important that the agency which releases keys not release the RSA
keys (in this case) but rather the session key (360 bits of DES key and IV) of
a particular conversation.  Releasing the RSA key makes the phone in question
insecure for all time, past and future.

(No, I don't advocate key registry -- but if it looks like we end up having it,
let's have it limited.  Meanwhile, it's perfectly reasonable to have an audit
trail of all such taps made available to major news organizations immediately
and eventually to the person targetted -- so that any Nixon-like abuses would
get caught and prevented.)

Carl Ellison, Stratus Computer Inc., M3-2-BKW, 55 Fairbanks Boulevard,
Marlborough MA 01752-1298 (508)460-2783 FAX: (508)624-7488

Re: New risk reports (Bowen, RISKS-13.87)

Pete Mellor <>
Mon, 2 Nov 92 20:30:01 GMT
Please see also:

  "Living with Risk", The British Medical Association Guide, John Wiley & Sons,
  1987, ISBN 0 471 91598 X, 16.45 sterling. (Winner of the 1988 Science Book

Peter Mellor, Centre for Software Reliability, City University, Northampton
Sq., London EC1V 0HB, Tel: +44(0)71-477-8422, JANET:

ASEE '93 EPPD Call for Papers

"Ken Sollows" <>
3 Nov 92 09:56:12 ADT
                          CALL FOR PAPERS

                    1993 ASEE ANNUAL CONFERENCE
                         JUNE 20 - 24, 1993

     Presentations and papers are invited on educational aspects of Engineering
and Public Policy.  Any related topic will receive consideration, however,
suggested topics for sessions are the following:

          *    Energy and Environmental Policy
          *    The Role of Colleges of Engineering in Shaping
                    Public Policy
          *    Public Policy in the Undergraduate Engineering
          *    Governmental Initiatives in Engineering Education
          *    Educational Policy and Economic Growth

Deadline:     500 word abstracts due December 1, 1992

     Presentations will be selected by the EPPD program staff based on
abstracts only.  Authors who also wish to submit their papers for publication
in the conference Proceedings must submit a draft for peer review by January
15, 1993.  There will be a page charge for publication.  Include title,
author's name, work address, and telephone number.  Abstracts and papers should
be submitted to the EPPD Program Chair:

     Dr. P. Paxton Marshall, Department of Electrical Engineering
     University of Virginia, Thornton Hall, Charlottesville, VA 22903-2442
     Tel: (804) 924-6076 Fax: (804) 924-8818  e-mail:

Ken Sollows, Dept. of Engineering, UNBSJ
Email:   Ph: (506) 648-5583   FAX: (506) 648-5528

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