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 18 Issue 70

Friday 20 December 1996


o BART software crash and system delays
o Problems of "unforeseen" system aging
Nick Brown
o LAPD Database Flaws in L.A. Weekly
Jeremy Leader
o The Risks of Security
Robert J. Perillo
o ATM gangsters
Andrew Weir
o Justice Wants to scrutinize Parolee computer use
Pete O McVay
o SATAN Survey
Christopher Klaus
o PCs and configuration management
Jeremy J Epstein
o Arrogance of Micro$loth Products - BEWARE!
Roland Giersig
o Re: Cookies
Mark J Cox
o More on the phf bug in NCSA httpd...
Matthew Healy
o 9th annual FIRST conference: Call for Papers
Stephen E. Hansen
o Info on RISKS (comp.risks)

BART software crash and system delays

"Peter G. Neumann" <>
Fri, 20 Dec 96 9:56:52 PST
Bay Area Rapid Transit (BART) had another bad day.  At 7am, a ghost train
appeared at the San Francisco 24th Street station, requiring manual
operation through that station.  Independently, three trains had to be taken
out of service because of mechanical problems.  All of this caused a
15-minute delay systemwide.  Later, a computer crash caused delays up to 30
minutes systemwide, from 5:50pm to 9:45pm on 19 Dec 1996.

BART also had a serious power cable outage in the transbay tunnel on 12 Dec
1996 (not previously reported here by itself, because of its lesser
relevance to the computer systems -- although it certainly had a major
effect on the system as a whole).  That cable problem was traced to sloppy
maintenance after the cable was damaged way back when it was installed back
in the early 1970s.  BART now observes that an overall cable overhaul had
been considered prior to the 12 Dec outage as an urgent step in upgrading
the aging infrastructure.

Problems of "unforeseen" system aging

+33)388412674 <"Nick BROWN " <> (Tel>
20 Dec 1996 09:55:44 +0000
Reading some back issues of RISKS, I realised how many of the incidents and
problems reported are due to systems (embedded and otherwise) getting old.
The "system" (made up of the people who use it, as well as all the computer
"systems") has to be able to cope with the oldest and newest technology in
it, and all the breakdowns in all the (non-upgradable) component systems.
With the pace of change in technology (try buying a 1 megabyte SIMM), we are
going to find ourselves more and more unable to maintain the systems we

Current examples are such things as: air-traffic-control computers being
kept going long after the manufacturer can officially no longer supply the
spares, by wizened (i.e., over-45) hardware engineers with soldering irons
and a bag of those big fat 20-watt resistors; car "computers" which tell you
the car's average speed over the last hour, for the first four years of the
car's life, and then flash "88 8888" at you unless you spend $1250 for a
replacement unit; a four-year-old PC for which you can't buy a new disk
drive (the BIOS can't handle anything bigger than 512 MB).

Future examples: anything with a smart card in it; the often-documented
problem of reading information stored on 30-year-"guaranteed"-lifetime
optical disks in 30 years when the disk might be readable, but no computer
system can connect to the drive; and of course the year 2000.

People are very good at adapting to change (once they get over the emotional
hurdle of accepting it's going to happen) and working with the limitations
of old and new; just look at any home with items as diverse as a TV and a
toilet.  Computer systems aren't at all good at it, and anything with
firmware is just disastrous.

Here's a little test for readers who work in systems specification.  Have
you ever seen a requirements, functional, or design specification for any
computer application system that specified not just the hoped-for start date
for production use of the system (you know, the one where you have to
subtract a year for political reasons, even though you know there's no way
it'll be ready in time), but also the END date, after which the system would
be taken out of use and replaced with something else?  For advanced
students: what would have been the effect on any given project of doing so?

Nick Brown, Strasbourg, France

  [The juxtaposition of this item with the BART
  item is of course purely coincidental(!).  PGN]

LAPD Database Flaws in L.A. Weekly

Jeremy Leader <>
Fri, 20 Dec 1996 13:00:39 -0800
This week's L.A. Weekly (Vol. 19, No. 4, page 15) has a story about
inaccuracies in the Los Angeles Police Department's Police Arrest and Crime
Management Information System (PACMIS).

The following is my summary of some RISKy aspects of the story.

The article focuses on a doughnut shop in Van Nuys.  Because the shop is the
closest establishment to the street in a mini-mall, many incidents nearby
bear its address in police records.  That may be useful for getting officers
to the scene quickly, but it resulted in the shop being described as a
"disorderly establishment" because of the number of crimes recorded at its
address, the majority of which had no connection with the doughnut shop.

The article paints PACMIS records as being very inaccurate.  The examples
cited include multiple entries for the same incident, and an entry that
described a nearby jay-walking citation as a "felony prostitution" arrest on
the premises of the doughnut shop.

PACMIS is not intended to be used for "evidentiary purposes", but the story
claims PACMIS reports are used to influence zoning board hearings and other
nuisance-abatement measures.

The story doesn't describe what PACMIS's original purpose was.

It sounds to me like a typical instance of the risks of inaccurate data and
of using data for other purposes than those for which it was collected.

Jeremy Leader, Tujunga, CA, USA

The Risks of Security

Thu, 19 Dec 96 16:41 EST
The Superintendent of the Palisades Park, NJ, school system had to explain
to the School Board an $875 bill from a 16-year-old "hacker" who was hired
to break into the schools computer system. The 19 Aug 1996 meeting was
reported by the AP, and was carried by most national newspapers, such as the
*Richmond Times-Dispatch*, 22 Aug 1996, "Hacker frees transcripts", page

It seems that some students or former students, whose plans had changed,
desperately needed transcripts sent off over the summer. The computer and
database containing the students' records were locked via passwords, and no
one who knew the passwords could be reached.  The principal and former vice
principal were on vacation and unreachable. The school employee who had the
codes was recently incapacitated by a stroke. Members of the guidance
department were furloughed for the summer because of the school's budget
crunch and could not be found.

The school's computer coordinator asked the 16-year-old "computer whiz" to
break into the system, and unlock the files so the various transcripts could
be printed. He did, and billed the school system $25 an hour for 35 hours of

  I believe this story shows the Risks of security, password access, and
encryption systems, and the need for built-in "Key Recovery"
architectures. Businesses and other organizations cannot be put at Risk,
when critical information cannot be unlocked because of an employees
absence, incapacitation, or lost keys and passwords.

  Companies like AccessData, Orem, UT, do quite a lot of business in terms
of password recovery for unlocking files. Unfortunately, these techniques,
or the techniques used by the "hacker" would not be effective in systems
using modern security and cryptography.

  "Key Recovery" or "Key Archival" has long been recognized as a necessary
function and service of security and cryptographic systems.  While it is
true, that in the U.S., a Court could order that one of the archived
keys/passwords be released to the court, there are legal and procedural
safeguards in place.  There are far greater risks, such as losing the
key/password, and having critical information lost and undecipherable.  In
the case above, the future livelihoods and careers of the students who
immediately needed their transcripts would have been put at risk if they
were unable to unlock the passwords.

Robert J. Perillo, CCP       

  [Reminder: RISKS readers will undoubtedly be able to make the distinction
  between "key recovery" for stored data and "key recovery/archive/escrow/
  or-whatever" for communications.  The situations are quite different.
  RISKS readers will of course also be familiar with the potential risks
  inherent in the presence of any mechanism that allows key recovery by an
  untrustworthy third party.  PGN]

ATM gangsters

Andrew Weir <100637.616@CompuServe.COM>
20 Dec 96 15:13:17 EST
Much British media panic has been devoted to the recent conviction of an
"ATM gang" of high ambition. A collection of high-grade villains with
impeccable pedigrees in robbery, gangsterism and drugs dealing over 30 years
compelled a software expert who was in prison for attacking his wife and
child to help them in their enterprise. The man revealed his role to a
prison chaplain and subsequently acted as an undercover informer on his

The plot was to tap telephone lines carrying encrypted ATM card details to
and from the banks, especially the Visa and Access (Mastercard's name in the
UK) centres in Essex. Having decrypted the information, fake ATM cards with
genuine cardholders' details would be manufactured from the 140,000 blanks
they had bought. Teams of associates armed with the cards would then assault
thousands of ATMs in the UK and abroad.

The media response, based on the claims of the prosecution, said the plot
had "put the entire banking system in danger". Not only that, but
prosecution estimates of the potential proceeds were put at about L800
million, with chief counsel adding that in fact, "the sky was the limit".

The claims of the prosecution were alarmist, even if the conspirators were
in deadly earnest, and bear the hallmarks of media fantasies about the true
level of risk in bank security (see suspicions about the Sunday Times
reporting on this in RISKS-18.17). The logistics alone of the planned ATM
raids would have been horrendous. It would have been extremely difficult for
a "raider" to use more than one ATM card after another at one machine
without raising immediate suspicions. Typically, ATM cards have withdrawal
limits no higher than L200 in the UK, often much lower, depending on the
status of the account.

If one imagined that one person could cover, say, 50 machines in a -- very
busy -- day and got L200 from each machine, he would clear L10,000 in one
day. If, say, 100 gang members could withdraw that much each per day (a
generous estimate), it would take them 160 days of continuous raiding to
reach the prosecution figure of L800 million. It seems highly probable that
within a short time of the raids beginning, alarm bells would go off
throughout the banking system and ATMs would either be closed down, put
under surveillance, or new, lower limits on all cards imposed by the
banks. (There would be loss of a public confidence in ATMs, but hardly a
collapse of the banking system). Security cannot be good in a gang that big,
and the chances of one of them being caught and spilling the beans,
especially after the tremendous hue and cry that would have gone up, would
have been very high.

Code-breaking gangsters?

But could they have got that far? Newspaper reports failed to emphasise the
all-important question as to whether the encrypted information could be
decoded.  Defence counsel were scathing about the possibilities and called
experts to testify that it was effectively impossible. One of the defence
barristers said: "The basic method was fatally flawed ... because the
encryption system used by the banks is so secure that no current technology
available in the world, not even the combined expertise of the world's
leading scientists, is capable of breaking it."

The judge appeared to accept this, with a proviso. Addressing the
defendants, he said in sentencing them: "It was not possible for you, with
the equipment and expertise then at your disposal, to carry out this fraud
to a successful conclusion. There is, in particular, no evidence that the
cards recovered by the police would then work or that the codes had then
been broken. However, beyond that I'm not prepared to go. I do not believe
it is necessary to go further but for the avoidance of doubt I make it clear
that it would, in my judgment, be irresponsible and wrong on the basis of
the information before me to accept any additional assurances along the
lines that this is a fraud that no one could ever commit."

Lawyers being what they are, the judge could not exclude the possibility
that the decryption was possible, even though the remoteness of that
possibility does not seem to have struck home, particularly when it is
considered that the gang's only computer expert was working against
them. The gang's expert claimed no expertise in cryptography and yet said in
evidence that there had been a successful decryption dry run. This was not
corroborated elsewhere, and the judge did not accept it.

The case in court did not, as a result, measure up to the headlines. In
fact, the prosecution had decided from the start only to charge the men with
conspiracy to steal, which carries a maximum sentence of seven years,
instead of conspiracy to defraud, which carries a maximum of 14 years. For
the latter charge to succeed, the Crown would have had to convince the jury
that the defendants had "a reasonable chance of success". Despite the gang
spending some L100,000 in the purchase of equipment, making numerous
clandestine visits to British Telecom telephone exchanges, and suborning
about three BT engineers, the prosecution realised such a charge would fail.

The judge kept his head and, in the end, the ringleader was sentenced to
only five years in prison, some subordinates to four and three years, and
the man whose heavily guarded country home was the headquarters for the plot
only got a two-year suspended sentence. It is worth remembering that
sentences reflect the convicted person's criminal record, and the "form" of
these men was awesome.

Computerised fraud on a gigantic scale has been a major focus of media panic
and large-scale exaggeration in the past. The criminal community, it seems,
was guilty of believing everything it read in the papers.

Justice Wants to scrutinize Parolee computer use

Pete O McVay <>
Fri, 20 Dec 1996 13:14:18 -0500
In a copyrighted story dated December 19th, Rex Nutting of TechWire reports
that the U.S. Justice Department is considering new rules to restrict access
of Federal Parolees to computers and the internet.

Restrictions being considered include "requiring parolees to keep a daily
record of their computer use, requiring parolees to agree to unannounced
inspections of their computers, banning the use of private or public
computer networks without prior permission and banning the possession or use
of data encryption programs."

Lawyers and law enforcement experts termed the new rules "silly" and
"unenforceable".  Regardless of these opinions, I attach a more sinister
meaning to this proposal.  The U.S. Justice Department is reinforcing a
prevalent government attitude that private citizens use the internet
primarily for criminal purposes.

For some reason, it is all right for large corporations or organizations to
surf the net, and also to use encryption to protect their data and financial
transactions.  But the Justice Department rules imply that private citizens
doing the same thing must have something to hide, or are searching for
illegal materials--bombs, pornography, electronic vandalism methods, etc.

To my knowledge, parolees are not required to report visits to their local
libraries, where much of the same information can also be found. Perhaps we
need laws that require that borderline institutions such as libraries not be
located in high-crime areas or near prisons...

SATAN Survey

Christopher Klaus <>
Fri, 20 Dec 1996 09:03:40 -0500 (EST)
Here's some extremely alarming information made available by Dan Farmer.  It
has a good break down of sampled sites that were assessed and what the
number of them were vulnerable or misconfigured.

I'm sure these sites probably didn't use SATAN ( or ISS
( to secure themselves. 8-)

The survey is available at

P.S.  In light of security experts conducting these surveys, I'd recommend
using tools like RealSecure and Courtney to detect when you unknowningly
become a statistic in these surveys.

... I guess it is accepted practice to scan at will as long as you do
not break in?  Christopher William Klaus, Internet Security Systems, Inc.,
Ste. 660, 41 Perimeter Center East, Atlanta,GA 30346 (770)395-0150

PCs and configuration management

Fri, 20 Dec 1996 09:07:16 -0500
It's no secret that PC hardware manufacturers modify machines continuously
without changing model numbers, thus making it very hard for end users to
maintain consistent configurations.  These changes are usually swapping one
model of peripheral for another or one brand of chip for another, and less
commonly changing board layouts.  These changes are done to reduce
manufacturing cost, improve reliability, and/or deal with parts

According to the December 1996 edition of Byte (pg 28), at least one large
PC vendor recently made an incompatible BIOS change without changing the
BIOS revision label displayed at boot time.  The problem was discovered
because one machine ran Windows NT, while an ostensibly identical machine
wouldn't.  The RISKS of poor configuration management, driven by the
industry drive for reduced cost and increased performance, claim another

[As an aside, software vendors have taken to making changes without changing
the version number also, in a process known as a "blind update".  JJE]

  [It is the next step in the process after the "blind date".  PGN]

Arrogance of Micro$loth Products - BEWARE!

Roland Giersig <>
Tue, 10 Dec 1996 11:37:30 +0100
This is about a "feature" in WinWord 6 that a colleague stumbled across. The
incident shows the full arrogance that MS products exhibit when dealing with
situations with ambiguous semantics.

The said colleagues job was to prepare monthly reports about estimated and
real work-power efforts regarding some projects work-packages. For the first
few months he wrote these reports using the WinWord installed on his
laptop. Recently he switched over to using the WinWord installed on a
central NT server using WinCenter to access it remotely from his Sun
workstation. As it is common practise with such recurring reports, he opened
the report from last month to change the figures and save it under a new

Now the figures were listed in a table, and the sum of each column was
calculated via the "Table Formula Sum(above)" function. Before he started
changing the numbers, he accidentally pushed F9 ("Update Fields") while the
cursor happened to be in the sum field.

Can you imagine how big his surprise was when suddenly the column sum
CHANGED before his eyes? Remember, he didn't change anything! And WITHOUT
WARNING! And to add insult to injury, the sum was WRONG!

Avid MS "fans" surely know by now what was wrong: the LANGUAGE
settings of the two Windows versions differed! And thus the symbol for
the decimal point was `.' on the one machine and `,' on the other.

The arrogance? NO WARNING! And the sum function does not even just truncate
then numbers, no, it somehow interprets the comma or period as a list,
because summing "1,4" and "2,3" gives...  TADAH! "10"!!! (it used to give
"3,7" with the other language settings)

The RISK? I really wonder how many reports are out there with wrong numbers
because some poor dilbert-type employee typed it on his computer and her
boss printed it from another computer with different language
settings. Maybe even someone got degraded or fired "because s/he reported
the wrong numbers"!

Also, WinWord is the only editor I know where you open a file, close it
again and WinWord asks you if you want to save the changes!!

(Another example of built-in arrogance: I tried to import some ASCII-text
records into MS Access. Instead of asking about the format, Access silently
tried to interpret the text itself and finally reported "1746 errors

So the final lesson learned is:

          <>> MS documents ARE NOT PORTABLE! <<

(And another example of non-portabililty: MS Project stores the
workdays-per-week number as a PER-USER setting, not per-project!  Exchange a
Project with a colleague and BINGO! Everything gets re-scheduled.)

There are surely lots of other examples, maybe others would like to share
their "experiences" too.

BTW, I am sure that some of these "features" are or will get fixed. But I am
also sure that nobody will receive a bugfix or upgrade for free, as it is
common practise with other software companies. Instead you will be prompted
to "upgrade to Windows97 and WinOffice2000 for a real cheap $999.99 now and
your problems will be solved". Sweet arrogance!

My feelings are best reflected by this signature found on the Net:
 "Microsoft is not the ANSWER.
  Microsoft is the QUESTION,
  and the ANSWER is NO!"


PS: Sorry if this sounds very emotional, but I have already wasted
enough precious time with things like these.        (speaking only to, err, for myself)
ALCATEL Austria, Scheydgasse 41, A-1210 WIEN.    Phone: +43-1-27722-3755

Re: Cookies (Stuart, RISKS-18.68)

Mark J Cox <>
Fri, 20 Dec 1996 16:04:14 +0000 (GMT)
> Making Netscape's cookies file a symbolic link to /dev/null is also an
> effective way to disable cookies under UNIX.

There's been a lot of talk recently about disabling Cookie logs in Netscape
- theres a simpler (undocumented?) way of doing this you might want to
mention in a future journal.

In the Netscape preferences file there is an option "ACCEPT_COOKIE" that
gets set to "0" if you want to always accept them, and "1" to prompt the
user for every new cookie.  Setting it to "2" doesn't prompt the user and in
fact disables cookies altogether.

Mark Cox, Technical Director, UK Web ------
Latest news on the Apache Web Server -------

More on the phf bug in NCSA httpd...

Matthew D. Healy <>
Thu, 19 Dec 1996 19:58:18 -0500
I got e-mail from _many_ people pointing out:

   o this bug in phf and other sample CGI programs that come with
     the NCSA httpd distribution has been known since March 1996.

   o it allows many other tricks in addition to grabbing the /etc/passwd
     file.  If you have one of the buggy CGI programs installed, then
     intruders can use it to do essentially anything that can be
     done by whatever userid your httpd server runs under.

The degree of tact ranged from courteous to downright rude.  Some people
implied that I must be a grossly incompetent webmaster not to have fixed
this one months ago.  But this is an academic research facility, not the CIA
-- and even the CIA website did get cracked, though I don't know which hole
was exploited in their case!

I do try to keep up, but I am not a full-time security specialist; I do many
different things, and I'm usually behind on most of them.  After two weeks
wasted cleaning-up after the crackers, I am even farther behind than usual.

So, it seems to me that there are lessons to be learned from this episode on
several levels:

  o I personally am more conscious of security issues than I was before
    this attack.  I will spend more time keeping up with security alerts
    that might affect my site, and I will add scanning my webserver log for
    suspicious URLs to my list of things to check on a daily basis.  Of
    course, this will mean less time for my real work, and this does anger
    me.  Even a supposedly-harmless intrusion requires a responsible
    administrator to spend untold hours checking for damage, looking for
    backdoors and Trojan horses the intruders might have left behind, etc.,
    etc.  The cracker left a note claiming we had nothing to worry about
    because he didn't damage anything, but in fact he _did_ do a small
    amount of damage without apparent malicious intent.  And he did a large
    amount of damage to my confidence in the integrity of my systems!

  o Steps are being taken on an institution-wide level here at Yale to
    improve the channels for coordinating responses to things like this.
    When the wizards began checking other Yale servers for this hole, they
    discovered that our servers in the Medical school are not the only
    recent victims of phf attacks.

  o Perhaps the Internet-wide channels for propagating alerts need to be
    refined.  I believe part of the reason I missed this hole was the sheer
    number of alerts coming from various quarters that I and other
    overworked system administrators are expected to read.  It is simply not
    reasonable to expect that every system administrator will apply every
    recommended security patch every time yet another patch is released!
    There needs to exist a mechanism for prioritizing warnings according to
    the ratio of severity to ease-of-exploiting each threat.  The phf hole
    is so nasty precisely because anyone who is reasonably familiar with
    Unix can learn to exploit it in a matter of minutes.  And many crackers
    are exploiting this one right now.

9th annual FIRST conference: Call for Papers

"Stephen E. Hansen" <>
Thu, 19 Dec 1996 11:11:50 -0800
                  C A L L   F O R   P A P E R S
      The Forum of Incident Response and Security Teams (FIRST)
      Ninth Annual Computer Security Incident Handling Workshop

"Bridging the Borders - Incident Handling in an International Network"
                   Marriott Hotel, Bristol, England
          Monday 23-Jun-1997 to Friday 27-Jun-1997 (inclusive)

Abstract Submission Deadline:  15-Jan-1997.  The complete call for papers
can be found at .

Contact Information: for e-mail,
FAX: +1 415 725 9121 (Attention to: Stephen Hansen, Subject: FIRST 1997, Wkshp)
or or via post, Attn: Stephen Hansen, 333 Sweet Hall, Stanford University,
Stanford, CA, 94305-3090 USA

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