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RISKS-LIST: RISKS-FORUM Digest Friday, 15 January 1988 Volume 6 : Issue 10

FORUM ON RISKS TO THE PUBLIC IN COMPUTERS AND RELATED SYSTEMS ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

Contents: Multimillion $ Fraud Failed due to Computer Error (Frans Heeman) Library Privacy (Michael Wagner) A reverse Heisenbug: it's there only if you look for it (Dave Platt) "The Consultant" on TV (Jim Horning) The timewarps of '88 (Rayan Zachariassen)

The RISKS Forum is moderated. Contributions should be relevant, sound, in good taste, objective, coherent, concise, nonrepetitious. Diversity is welcome. Contributions to RISKS@CSL.SRI.COM, Requests to RISKS-Request@CSL.SRI.COM. > > > > > > > > > PLEASE LIST SUBJECT in SUBJECT: LINE. < < < < < < < < < For Vol i issue j, FTP SRI.COM, CD STRIPE:<RISKS>, GET RISKS-i.j. Volume summaries in (i, max j) = (1,46),(2,57),(3,92),(4,97),(5,85).

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From: Frans Heeman <mcvax!cs.vu.nl!frans@uunet.UU.NET> Subject: Multimillion $ Fraud Failed due to Computer Error Date: 14 Jan 88 09:01:57 GMT Organization: VU Informatica, Amsterdam

In the Dutch newspaper "De Volkskrant" of Tuesday january 12 and Wednesday january 13 1988, two articles appeared on a computer fraud that was discovered by ... an error of that same computer.

An employee of a bank in Amsterdam (name of the bank not mentioned) transferred $15.1 million to a Swiss account, using the computer. To make an international money transfer, two persons must give permission. Each of them has a secret password. The employee knew the password of one of his collegue's, and had a password himself, and thus could make the money transfer on his own.

On december 24, the employee tranferred $8.4 million and $6.7 million to a bank in Zurich. Due to a technical malfunctioning, the transfer of $6.7 million failed. After Christmas, other employees saw on their terminalscreen that the transfer had failed, got suspicious, and reported to their superiors.

According to the Volkskrant, many banks use the same system, and this method of fraud "occurs presumably more often, although the banks are very quiet about this". The employee is arrested.

This makes me wonder about fail-safe computers: a fail-safe computer would have failed to save the bank from THIS fraud :-) Frans Heeman, frans@cs.vu.nl

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Date: Fri, 15 Jan 88 14:02 CET From: Michael Wagner +49 228 303 245 <WAGNER%DBNGMD21.BITNET@CUNYVM.CUNY.EDU> Subject: Library Privacy (RISKS DIGEST 6.8)

In Risks 6.8, Steve Cisler wrote > This means that no one ... can get a profile of your reading habits > from checking old records. There are just not any--except overdue items ...

This comes up from time to time, but it's worth pointing out again. Don't forget to think about (and talk about) the backup system. This system, designed explicitly for the re-creation of old data in certain, failure situations, can be (mis)used to recreate the data in other situations unless the backup system is designed with data protection and selective erasure in mind. Michael [The old Contragate so-you-thought-you'd-deleted-it problem... PGN]

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Date: Fri, 15 Jan 88 10:05:35 PST From: coherent!dplatt@ames.arc.nasa.gov (Dave Platt) Subject: A reverse Heisenbug: it's there only if you look for it

I've encountered a marvelous Heisenbug (a bug whose behavior changes when you look for it) involving TOPS Spool and MultiFinder. Yesterday, I installed MultiFinder on one of the Mac SE systems here at work. After rebooting, I found that TOPS Spool worked fine when the system was booted in Finder mode, but behaved erratically when the system was booted in MultiFinder mode. The primary symptom I saw was that TOPS Spool would spool the file to disk, but would not print it. The status display would indicated "Waiting; source: AppleTalk", and the printer's yellow status light would double-blink (indicating that the printer was waiting for data to be sent over AppleTalk). This wouldn't always occur, and didn't always occur at the same point in a file. I tried spooling one file several times, and the copies seemed to exhibit different behavior.

Finally, I noticed one critical clue: if I had turned "Print while I work" off, and then opened the TOPS Spool d/a and turned it back on, the spooler would not begin transmitting the file until I closed the desk accessory. Printing would then begin, and would continue to work properly until I opened the desk accessory again... at which point the current print job would hang!

So... hmmm... using the TOPS Spool desk accessory under MultiFinder causes the background printing task to stop working, but using exactly the same desk accessory, System, drivers, etc. works just fine if the system is booted under the Finder. What's the difference? Well, under MultiFinder, desk accessories are normally opened by a mini-application called DA Handler, so that they won't go away if you "Quit" from your current application. I tried opening TOPS Spool while holding down the Option key, which forces the desk accessory to run in the current application's context... and, lo and behold, background printing kept working! Apparently, the TOPS Spool desk accessory interferes with the background-printing task if it's run under DA Handler, but not if it's run under the current application (Finder, in my case).

So... this is really a reverse Heisenbug, of sorts... the software works unless you look to see whether it's working, at which point it stops working!

Dave Platt UUCP: ...!{ames,sun,uunet}!coherent!dplatt Internet: coherent!dplatt@ames.arpa, ...@sun.com, ...@uunet.uu.net

[For those of you who weren't in on the original flurry of Heisenbugs, see RISKS-4.30 through 36, and a few subsequent issues. PGN]

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From: horning@src.dec.com (Jim Horning) Date: 15 Jan 1988 1447-PST (Friday) Subject: "The Consultant" on TV

I got many responses to my question. Here are some relevant excerpts:

From: olling@tcgould.tn.cornell.edu (Cliff Olling)

I caught 2 or 3 episodes of it quite by accident about 6 months to 1 yr ago. It was showing on one of the PBS stations on our cable here in Ithaca. I think the PBS stations are in Scranton, PA, and Binghamton & Syracuse, NY.

As for the content, I found it interesting from the theatrical as well as the technical sense. The consultant didn't seem to be blatantly "bat", and I don't remember actually took any money. He seemed more like an adult version of the typical teenage hacker stereotype. The technical parts (actually typing on terminals, using modems, etc.), actually seemed fairly realistic. There were no whirling tape drives or modems going Beep-Boop-Beep-Boop a'la War Games. All in all, very little suspension of disbelief was required.

From: davy@intrepid.ecn.purdue.edu (Dave Curry)

"The Consultant" BBC television series was aired on the Arts & Entertainment Network (a cable channel) on Monday evenings about two years ago. If I remember right, they broke it into five or six episodes instead of four, each was an hour long.

The series wasn't too bad... they actually used "computer words", and didn't do anything silly like make the terminal beep for each character it printed, etc. Some stuff was simplified for the general public, but overall I found it an enjoyable series.

The A&E Network tends to re-air most of their more popular shows every year or two.

From: watrous@aramis.rutgers.edu (Don Watrous)

I've seen it play on A&E (cable) a couple of times within the last year or two. ... I remember the characters and the premise, but don't recall being very impressed.

From: Lee Barford <barford%hplabsb@hplabs.HP.COM>

The Arts & Entertainment Network played it twice, about 18 months ago and again about a year ago.

[Some of this covered by comments from Brian Kantor, Scott C Crumpton, Dave Curry, Dwight D McKay, Alan Wexelblat, ... PGN]

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Subject: The timewarps of '88 [More Leap Year details -- SEE RISKS-6.4 to 7] Date: Thu, 14 Jan 88 22:16:10 -0500 From: Rayan Zachariassen <rayan%ai.toronto.edu@RELAY.CS.NET>

Not having anything better to do last New Year's evening, it seemed like a good opportunity to synchronize our computer clocks with reality. So, as the leap second approached, my finger was poised on the RETURN key. Poof, the New Year arrived and the clock was back in sync. Ten minutes later, the computer was half an hour into '88. Hmmm, didn't look right. For the next couple of hours, I was chasing the system clock the way a cat stalks its evasive prey.

A day or so later, the first reports appeared of other people having the same problem (by this time I was used to frequent timewarps on the system). The problem turned out to be caused by a classical programming error:

Macro arguments with side effects are Bad Style.

The problem was in the clock maintenance software in the kernel, where a C macro defined as:

#define MONTHSEC(mon, yr) \ (((((yr) % 4) == 0) && ((mon) == 2))? 29*SECDAY : monthsec[(mon) - 1])

was called using:

... MONTHSEC(--mon, year);

instead of:

--mon; ... MONTHSEC(mon, year);

The code was written after the previous leap year, and the double-evaluation of the first argument would not occur until another leap year. Some knee-jerk analysis of the problem wrongly blamed the leap second (what with all the publicity). Since most clocks and software don't know about leap seconds, this was not plausible.

Considering the 40000-odd (my estimate) computers that were affected by this problem, many many people were thinking of the careless programmer with warm, sizzling, thoughts. It didn't reflect well on the employer/vendor either, both in letting this problem slip by them, and in letting an apparent novice write such a critical section of code. I realize my criticism may be harsh, but it is coloured by the severity of the problem, having experienced it, and knowing the cause.

On a vaguely related matter, the latest issue of The Economist (9-15 Jan 88) has an article titled "Something Rotten in the State of Software". It is a 3-page overview of computer bugs, what causes them, and what to do about it. Several Risks issues, and people (Neuman, Parnas, Leveson), are mentioned.

Never trust computers. rayan

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End of RISKS-FORUM Digest ************************