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 17 Issue 28

Monday 21 August 1995


o Russian Hackers
PGN and Christopher Klaus
o ATC glitches, continued
o Medicare leak through FOIA analysis and 9 digit ZIP
Quentin Fennessy
o Disabling technology?
Geoffrey S Knauth
o "Safeware: Systems Safety and Computers" by Leveson
Rob Slade
Nancy Leveson
o Re: Insisting on explanations
Julian Thomas
o Re: Intel Warns of Marred Motherboards
Dave Porter
o Re: Intel-Hacking Conviction
Steve Pacenka
o Re: Stale accounts and lifestreams
Paul E. Black
o Re: Netscape security
Harlan Rosenthal
Nevin Liber
Phil Koopman
Bernard Gunther
o Re: "The Net" and "555-xxx" IP numbers
Zygo Blaxell
Matthias Urlichs
Colin Plumb
o Info on RISKS (comp.risks), contributions, subscriptions, FTP, etc.

Russian Hackers

"Peter G. Neumann" <>
Mon, 21 Aug 95 7:51:22 PDT

Court documents were unsealed on 18 Aug 1995 that implicated Russian computer hackers in about 40 transfers totalling more than $10 million from the Citibank electronic funds transfer system, between June and October, 1994. The hackers were caught as they were trying to move $2.8M. The bank indicated only $400,000 was actually transferred — which at first reading would seem to contradict the $10 million figure, except for the fact that Citibank noted that none of its clients lost any money, and that all of the transfers were either blocked or reversed. Six people have been arrested. 24-year-old Vladimir Levin (who worked for AOSaturn, a Russian software house, and who is currently under arrest in London) apparently had figured out how to get around or through the Citibank security system. [Source: An Associated Press item in the San Francisco Chronicle, 19 Aug 1995, D1.] Sounds like another case of reusable (fixed) passwords biting the dust?

[Christopher Klaus <> added the following info, based on a report of Voice of America correspondent Breck Ardery: The other five include two people in the U.S., two in The Netherlands, and one in Israel. PGN]

ATC glitches, continued

"Peter G. Neumann" <>
Mon, 21 Aug 95 7:59:32 PDT

Radio communications between pilots and air-traffic controllers vanished for one minute on 11 August 1995 (until the backup system could be engaged), over a 200,000 square-mile area including all of Washington state and parts of Oregon, California, Nevada, Montana, and Idaho. This problem resulted from a software glitch in a 2-mont-old $1.4 billion computer system at the regional center in Auburn, Washington, and was disclosed on 16 Aug. [This relatively minor outage follows on the much more major problems in Chicago (RISKS-17.21), Fremont (RISKS-17.24), and Miami problems (RISKS-17.26).] ``The FAA says the new system, which replaces one dating from the 1950s, is more reliable and flexible, safer, easier to repair and provides better voice quality when controllers talk to pilots.'' [Source: San Francisco Chronicle, 17 Aug, A6.]

Medicare leak through FOIA analysis and 9-digit ZIP

Quentin Fennessy <>
Sun, 20 Aug 1995 09:35:01 -0500

I read an article on Medicare in the 20 Aug 1995 _Austin American-Statesman_. The article was evidently done for the Cox Newspaper chain. The article talks of the deterioration of the service, and also touches on that fact that a handful of doctors earn a disproportionate share of Medicare funds paid out.

The article has a sidebar, which says, in short: Cox analyzed 100 million computerized Medicare payment records for the report. The information was obtained via FOIA. The doctors names were not released. Evidently there is an ongoing court case to release the doctors' names. Cox was able to identify some of the doctors. The doctor's id codes were obscured by Medicare, but the 9 digit zip codes of the doctor's offices were not. Cox was able to pinpoint individual doctors given this level of detail.

Risks: If information needs to be split into private and public components then care needs to be taken for the job to be done correctly. 9-digit zip codes divide the US into fairly small areas and so can (and have) given away the store.

This is not to say that I think this Medicare information should be kept secret. However, 9 digit zip codes in databases can be used to pinpoint all sorts of details about folks.

Quentin Fennessy

Disabling technology?

Geoffrey S Knauth <>
Mon, 21 Aug 1995 13:36:20 GMT

A close relative does cancer research at a very large company. She marveled when I described the power of the Web, but said she could never use it: employees are prohibited from doing most useful searches, because of fear that competitors might see activity and learn what they are working on. So much for enabling technology.

Geoffrey S. Knauth <>
Marble Associates, Inc., (617) 487-0050 CRASH-B Sprints, Cambridge Boat Club

"Safeware: Systems Safety and Computers" by Leveson

Rob Slade <>
Fri, 18 Aug 1995 16:43:51 EST


"Safeware: Systems Safety and Computers", Leveson, 1995, 0-201-11972-2, U$49.43
%A Nancy Leveson
%C 1 Jacob Way, Reading, MA 01867-9984
%D 1995
%G 0-201-11972-2
%I Addison-Wesley Publishing Company
%O U$49.43 416-447-5101 fax: 416-443-0948
%O 800-822-6339 617-944-3700 Fax: (617) 944-7273
%P 680
%T "Safeware: Systems Safety and Computers"

Leveson has produced a thorough and broadly-based overview of the literature, structures, and models of system safety. Throughout, there is a strong awareness of human factors and the human-machine interface (HMI). There is also mention of the social, political, and economic forces driving or impeding safety considerations. Several studies cited indicate the counter-intuitive result that safety is not a cost of production, but, rather, that it actually improves performance.

Despite the title, and some sections specifically directed at software, there is some difficulty in relating much of the material to the software development process. As Leveson, herself, points out, software design and programming is generally unresponsive to engineering models of risk assessment and quality control. Those chapters with "software" in the title show a marked decrease in citations. (This undoubtedly represents the actual state of the art, rather than any lack of research.)

(One micro-peeve is that although the bibliography has hundreds of entries, the examples are limited to a few dozen, with a handful reiterated throughout the book. These detailed case studies are quite clear, but additional incidents might have made the material both more interesting, and more convincing. Again, the examples have relatively little to do with software.)

This is a very realistic analysis of the current state of risk assessment and management, and of the social activity in relation to it. The book shows a society surrounded by accidents waiting to happen. There are, however, some directions which indicate hope for a safer future.

copyright Robert M. Slade, 1995 BKSAFWAR.RVW 950531

Postscriptum: Leveson has seen the draft of this review, and was surprised at my statements regarding the lack of specific application to the software development process and the limited number of examples. While the points she raised in her response are very important, I still find that my impression of the book is unchanged. However, this is only my opinion, and based on subjective feelings. I would like to repeat that the work itself is of the highest quality, and useful to anyone concerned with developing safe products.,, Rob Slade at 1:153/733
Author "Robert Slade's Guide to Computer Viruses" 0-387-94311-0/3-540-94311-0

Re: "Safeware: Systems Safety and Computers" by Leveson (Slade)

Nancy Leveson <>
Fri, 18 Aug 1995 17:46:12 PDT

Rob, Thank you very much for your very nice review. I do have a question on two parts, though, that I don't really understand.

Despite the title, and some sections specifically directed at software, there is some difficulty in relating much of the material to the software development process.

I'm a little surprised by this. Part 4 (pages 225-500 of the main text) is all about the software process except for one chapter on hazard analysis in general, and there is a 40-page chapter on the software and system safety process along with another chapter on management that includes process information. In addition, the first part of the chapters on software requirements, software design, human-computer interface design, and software verification of safety are devoted to the process related to that aspect of development and how safety affects it. Is there some part of the software development process that I left out? I purposely did not lay out one process because one process does not fit every project. Instead, I tried to provide enough information that people could tailor the general process I describe to fit their particular environment, project, personnel, and degree of risk.

(One micro-peeve is that although the bibliography has hundreds of entries, the examples are limited to a few dozen, with a handful reiterated throughout the book. These detailed case studies are quite clear, but additional incidents might have made the material both more interesting, and more convincing. Again, the examples have relatively little to do with software.)

I also am unclear about what you meant here. I have hundreds of software examples throughout the book: I use all the known and documented software examples about which anyone has any real information. Peter Neumann's book has a few more, but many of these are unrelated to safety (many are security and privacy-related). I have some that are not included in any of the other recent books.

Because of my fear of doing harm (I waited 15 years to write this book because I was worried that I might say something that might endanger people), I did not include anything in the book for which I do not have substantial evidence. I read over 500 books and papers on safety and engineering over the 7 years it took me to write this book, talked to hundreds of engineers who build such systems, and worked myself on dozens of safety-critical software projects in many different industries. My fear of doing harm is partially the reason for excluding rumored accidents that have not been investigated or documented by someone who participated on the project. Chapter 3 includes a lot of evidence from the social science and safety literature that shows that accidents are often blamed publicly on the wrong factors for various psychological, sociological, and political reasons. There is agreement and carefully documented evidence on this misattribution phenomenon. And stories taken from newspapers are written by reporters who are under time pressure to produce news immediately and not wait six months for an investigation of what really happened. Most of what I have read in some recent books, bboards, and newspapers about accidents that I am personally familiar with has been incorrect. Misleading and wrong information can be more dangerous than no information.

Perhaps the confusion arises from the appendices. These were included only because describing the better-known and researched accidents (about which we have enough information to really learn something) in the main text would have required people already familiar with these accidents, particularly safety engineers, to have to wade through a lot of pages unnecessarily. However, software engineers probably know little about them and need the information to understand some of the text. These well-researched accidents are mentioned a lot in Chapters 3 and 4 on the general causes of accidents---including organizational and managerial factors and human error---because they are the only ones we have adequate information about with respect to these particular factors. The computer-related accidents are spread throughout the book and not included in the appendices (aside from the Therac-25) because everything we know about them can be described in a paragraph or two.

A reason for using non-computer related accidents is that they provide important information about what needs to be done when computers are substituted for analog controllers. Virtually all system safety engineers agree that software-related accidents are not any different than those in which computers are not used---software engineers are causing the same accidents that other engineers learned how to avoid years ago. They (and I) feel that unless the software engineers learn those basic safety concepts that have been accumulated over decades by engineers, we are going to repeat the accidents of the past and kill thousands of people unnecessarily.


Re: Insisting on explanations (Green, RISKS-17.24, etc.)

Julian Thomas <>
Sat, 19 Aug 95 07:13 EST

The experience with Dell brings to mind my experience a number of years back with a bank when I did in fact receive a coherent explanation for a strange entry on an annual mortgage statement. I suspect that their DP manager must have found it very difficult to write the letter that identified the cause of the strange numeric entry as the result of having specified the account number rather than one of the dollar quantities in a formula!

The risk: longwinded COBOL variable names, I suspect.

Intel Warns of Marred Motherboards (Edupage, RISKS-17.27)

dave porter 21 Aug 1995 12:09:15 -0400 <>
Mon, 21 Aug 95 12:10:46 EDT

Since I own one of these motherboards, I'm interested in this bug. I'm still trying to find out the exact details of the failure mode.

However, the description quoted above doesn't quite reflect what's really going on. The workaround was a BIOS upgrade (which had the effect of disabling some performance-enhancing feature in the RZ1000; this therefore doesn't mean my criteria for "correcting" the flaw, but perhaps I'm just fussy).

Naturally, changing the disk BIOS has no effect on operating systems that don't use the BIOS for disk I/O. I think this is what they mean by OS/2 "disabling" the patch, but their choice of words somehow seems to be blaming OS/2 rather than the maker of the buggy board.

[You mean, this is putting the buggy before the buggyman? Dave thought there might be a pun on "buggy whips", but "bogey MIPS" might be more like it. PGN]
The RISK? Oh, I suppose the risk is something to do with expecting to get detailed, accurate, technical information about computer products which are marketed to the technically naive.

Re: Intel-Hacking Conviction (Kabay, RISKS-17.23)

Steve Pacenka <>
Sat, 19 Aug 1995 17:00:54 GMT

M.E. Kabay cited a lesson of the Randal "Perl" Schwartz conviction:

Comments from MK: Another story confirming the old principle that you do NOT attempt to improve security by busting it without getting _written_ authorization from an appropriate officer of the organization. This is known as the CYA principle.

That's a starting point for debate in Usenet news that is extrapolating from this case. Two questions have been most interesting to me, as a person with increasing LAN and Internet access admin responsibility.

Some asked a speculative question specific to this case, without seeing the court testimony: is a computer crime law being misapplied to punish transgressions within a company, when the law's primary intent must have been to deter and punish thieves, spies, and damagers? If there is an element of this present, is there now a greater personal risk of exposing computer security risks in one's company? If so, too many professionals could infer that the lesson from this case is MYOB rather than CYA.
-- Steve Pacenka NY State Water Resources Institute @ Cornell University ## Email to for info about the Randal Schwartz computer security case.

Re: Stale accounts and lifestreams (Ewing, RISKS-17.27)

Paul E. Black <>
Fri, 18 Aug 1995 13:31:40 -0600

In Risks Digest 17.27 Martin Ewing ( writes

... Dave Gelernter at Yale has developed a "lifestream" database model which would capture and organize all your electronic data, starting with your birth certificate. ...

There is no clear distinction between relevant data (to be included) and irrelevant data (to be excluded). Instead there is a gradation from vital information to utterly useless junk. If one has a rare medical problem, it may be very important to know the medical histories of parents and relatives. Thus any drugs my mother took are an important part of who I am, so my "lifestream" begins even before my birth certificate. If my house is discovered to be in a geologically unstable area, repair records before I bought the house may be important in deciding whether or not to take preventive measures. The history of those that did the repairs may be important, too. But I doubt I'll ever need to know who the lead drummer for the Eagles was.

Attempting to have all of one's data in one place will not be a breakthrough: either everything will be included, in which case storage is problematic and finding pertinent information will be hard, or there some items will be left out, in which case it must be tracked down in outside repositories.

Paul E. Black Laboratory for Applied Logic, Brigham Young University
Provo, Utah 84602 +1 801 378 8113 (

Re: Netscape security (Shank, RISKS-17.27)

"Rosenthal, Harlan" <>
Mon, 21 Aug 95 14:02:54 -0400

One message emphasizes the break; another emphasizes how much work went into it. While not expecting absolute security, I feel that the second underestimates the value of even a single credit-card number, and overestimates the difficulty. Optimize the cracking process, build bit-slice hardware dedicated to the purpose, and the cost (and time) will come down; flood out a few hundred orders on a stolen credit card, and if even half of them get delivered you win. Not to mention the inconvenience to the true cardholder.

Just picture the fun of having some random hacker break your message (even if he has to leave his computer on for a few weeks), order a few thousand dollars worth of stuff on your credit card, and POST YOUR NUMBER on the local BBSs. You'll be cleaning up the paperwork for the next year.

No, thanks. I get nervous enough giving my number to these people anyway, having had a problem with a dishonest employee at a mail order house use my [among many others] number improperly. The last thing I want to do is ship it over a medium which goes through an unknown number of other people's systems on the way.

-Harlan Rosenthal

Re: Netscape security (Shank, RISKS-17.27)

Nevin ":-]" Liber <>
Fri, 18 Aug 1995 14:16:25 -0700

This type of cost analysis is only valid *if* the user of the computing power has to make a tradeoff between using it for this purpose and other useful work. If these machines would otherwise be idle, this computing power is virtually free (imagine if everyone ran RC4-40 cracking software instead of screen savers...). Also, how much cheaper does the computing power get if you allow, say 30 days to crack a message? How much cheaper is the computing power going to be next year or the year after that (assuming the data still retains its value; more on this below)?

How valuable are credit card numbers? A reasonable assumption could be the credit limit on the card. My credit limit per card is certainly well within the ballpark of the $10K cost you associate with cracking a message, and I would guess that most non-students who have the equipment to surf the Internet have a similar amount of credit available.

The other aspect to determining the level of security needed is the duration that the information retains its value. My primary credit card has had the same number for the last five years, and I don't see it changing in the foreseeable future, barring someone else "stealing" it. This, combined with credit limits usually going up over time, makes this data valuable *indefinitely*.

> 3. Inside the US, software can support a range of stronger encryption
> options, including RC4-128, which is 2^88 times harder to break.

Irrelevant. How many sites on the Internet are going to want to deal with US-only transactions?

The other question to ask is who exactly is assuming the risk: Netscape, Visa, or consumers directly?

Nevin ":-)" Liber nevin@CS.Arizona.EDU (520) 293-2799

Re: Netscape security (Shank, RISKS 17.27)

Phil Koopman x1624 <>
Fri, 18 Aug 1995 15:56:08 -0400 (EDT)

In "Netscape Security" (RISKS 17.27) Peter Shank argues that RC4-40 is currently adequate for $10,000 dollars worth of security, because that is approximately how much it costs to crack the encryption.

Unfortunately for that argument, compute power tends to get cheaper over time. Using an arm-waving rule of thumb of 2x more MIPS per dollar per year, RC4-40 might be "trusted" for protection over time as follows:

1995 $10,000
1996 $5,000
1997 $2,500
1998 $1,250
1999 $625

$5,000 credit limits are not uncommon. So it seems that very soon RC4-40 won't be secure enough to really trust with credit card numbers.

The RISK to me seems to be neglecting the relentless exponential growth in compute power when doing encryption/security analyses. I imagine the costs of picking an inappropriate standard method and then changing it could be significant.

Phil Koopman United Technologies Research Center (UTRC) 411 Silver Lane
East Hartford, CT 06108 USA (203) 727-1624

Re: Netscape security

Bernard Gunther <>
19 Aug 95 11:27:12 EDT
[Many TNX to all of you who submitted comments on the Netscape situation and its deeper issues. Phil Koopman's point was noted by more respondents than I care to enumerate. Bernard Gunther's message added another view as well. PGN]
> I have a friend whose purse was stolen and in two months about $25,000 worth of fraud was committed just using the check book, credit cards and ID's. If a single decryption is a break-even proposition today, tomorrow it will be cheap. Clearly, RC4-40 is only temporarily good enough. RC4-128 sounds like a better bet.
Bernard Gunther

Re: "The Net" and "555-xxx" IP numbers (Bernstein, RISKS-17.26)

Zygo Blaxell <>
Wed, 16 Aug 1995 00:17:41 -0400

<> (and the IP equivalent of a 555-xxxx number is
>Yeah. Unfortunately, typical IP software will silently convert 345 into
>89, which is a valid number. A better solution would be to allocate a
>set of IP addresses for use in movies. How about

No...apart from 43 being a class A network (which means it's, not, it already belongs to a NSP in Japan. There is already an IANA-sponsored test network at, which will work just fine as long as the movie requires only one class C subnet. ;-)

Zygo Blaxell, former sysadmin and current guru for the Univ. of Waterloo Computer Science Club; current sysadmin for,

Re: "The Net" and "555-xxx" IP numbers (Bernstein, RISKS-17.26)

Matthias Urlichs <>
20 Aug 1995 15:24:10 +0200

How about 10.anything? That's defined as site-local, see RFC 1597.

Matthias Urlichs Schleiermacherstrasse 12, 90491 Nuernberg (Germany) 42

Re: "The Net" and "555-xxx" IP numbers (Bernstein, RISKS-17.26)

Colin Plumb <>
20 Aug 1995 00:55:30 -0600

How about You'd have a hard time hurting another system using that. Or, if you want to make it more obviously invalid, use 383, 639 or 895.x.x.x . Of course, to be really futuristic, we need the IPv6 equivalent...


Please report problems with the web pages to the maintainer