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RISKS-LIST: RISKS-FORUM Digest Friday 28 July 1989 Volume 9 : Issue 8

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

Contents: Returning before departing on airline reservation systems (Gary McClelland) Sun security problem: restore (J. Paul Holbrook) Computer condom? (Jeff Stout) Robert Tappan Morris indicted (Steve Den Beste) Re: UK Defence Software Standard (Mark Moraes, Douglas W. Jones) Polling vs. interrupts (Douglas W. Jones) Software Engineering Models (John (J.G.) Mainwaring) Single Point of Failure for Internet Management (Kee Hinckley) DARPA contract & AI for moving targets (Bob Estell) Two-Word Last Names and Other Amusing Database Stories (Gary McClelland) Credit card issuers invade cardholders' privacy (Andrew Klossner) Re: windowless cockpits (Andrew Klossner)

The RISKS Forum is moderated. Contributions should be relevant, sound, in good taste, objective, coherent, concise, and nonrepetitious. Diversity is welcome. * RISKS MOVES SOON TO csl.sri.com. FTPable ARCHIVES WILL REMAIN ON KL.sri.com. CONTRIBUTIONS to RISKS@CSL.SRI.COM, with relevant, substantive "Subject:" line (otherwise they may be ignored). REQUESTS to RISKS-Request@CSL.SRI.COM. FOR VOL i ISSUE j, ftp KL.sri.com[CR]login anonymous (ANY NONNULL PASSWORD)[CR] get stripe:<risks>risks-i.j ... (OR TRY cd stripe:<risks>[CR]get risks-i.j Vol summaries (i.j)=(1.46),(2.57),(3.92),(4.97),(5.85),(6.95),(7.99),(8.88).

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Date: 25 Jul 89 15:23:00 MDT From: "Gary McClelland" <gmcclella@clipr.colorado.edu> Subject: Returning before departing on airline reservation systems

From the "Rumor Roundup" column in DIGITAL REVIEW (trade newspaper that tracks DEC doings) of 17 July 1989:

My DEC friends tell me that DEC employees now have a special way of traveling back in time. It seems that a memo on the internal electronic bulletin board goes on at great length about how to take advantage of a loophole in the rules governing domestic discount airfares. By booking the return flight as the departing flight, and the departing flight as the return flight, the airline computer system thinks the traveler is staying over the weekend. Apparently, the reservations program does not understand that people have to leave before they can return.

Gary McClelland, gmcclella@clipr.colorado.edu

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From: cert@SEI.CMU.EDU Subject: Sun security problem: restore Date: Wed, 26 Jul 89 09:20:48 EDT Sender: ph@SEI.CMU.EDU

A security hole has been found in SunOS restore. This problem affects SunOS 4.0, 4.0.1, and 4.0.3 systems. It does not appear in SunOS 3.5. The problem occurs because restore is setuid to root. Without going into details, is sufficient to say that this is a serious hole. All SunOS 4.0 installations should install this workaround. Note that a user does need to have an existing account to exploit this hole.

There are two workarounds that will fix the problem. The first is slightly more secure but has some side-effects.

1) Make restore non-setuid by becoming root and doing a chmod 750 /usr/etc/restore

This makes restore non-setuid and unreadable and unexecutable by ordinary users.

Making restore non-setuid affects the restore command using a remote tape drive. You will no longer be able to run a restore from another machine as an ordinary user; instead, you'll have be root to do so. (The reason for this is that the remote tape drive daemon on the machine with the tape drive expects a request on a TCP privileged port. Under SunOS, you can't get a privileged port unless you are root. By making restore non-setuid, when you run restore and request a remote tape drive, restore won't be able to get a privileged port, so the remote tape drive daemon won't talk to it.)

2) If you do need to have some users run restore from remote tape drives without being root, you can use the following workaround.

cd /usr/etc chgrp operator restore chmod 4550 restore

This allows the use of restore by some trusted group. In this case, we used the group 'operator', but you may substitute any other group that you trust with access to the tape drive. Thus, restore is still setuid and vulnerable, but only to the people in the trusted group.

The 4550 makes restore readable and executable by the group you specified, and unreadable by everyone else.

Sun knows about this problem (Sun Bug 1019265) and will put in a more permanent fix in a future release of SunOS.

J. Paul Holbrook, Computer Emergency Response Team, Internet: <cert@SEI.CMU.EDU> (412) 268-7090 (24 hour hotline)

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Date: Mon, 24 Jul 89 10:59:30 PDT From: jstout@atc.boeing.com Subject: Computer condom?

[From the Seattle Weekly, 5/3/89]

PUT A CONDOM ON YOUR COMPUTER

Every worry that your computer might be hanging out in a network where it will pick up some disgusting virus? Empirical Research Systems of Tacoma suggests you supply it with one of their "computer condoms". This high-tech prophylactic is a combination of hardware and software embodied in a controller card that simply replaces the one already in the machine. Rick Cummings, the company's president, says the system "stops all viruses" by monitoring the user network, the keyboard, and the program in use. He notes that the system is programmable to alter the parameters of its control on any given machine, but he guarantees that, "when programmed to your requirements, it will not allow viruses to enter."

The technology was developed through successful efforts to protect a group of European banks from the massive virus that penetrated European computer networks last autumn. "Naturally these became our first orders," Cummings says. He has since picked up an additional 2500 firm orders in Europe, with 5000 more contingent on inspection of the product. In the United States, the product has been reviewed by Boeing Computer Services and computer technicians at the UW. It will be on the domestic market "early next autumn at a cost of under $1000," Cummings says.

[An untapped market for LaTex? --JCS]

Jeff Stout Electrons: jstout@atc.boeing.com, uw-beaver!bcsaic!jstout Molecules: Advanced Technology Center, Boeing Computer Services, M/S 7L-64, P.O.Box 24346, Seattle, WA 98124-0346

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From: denbeste@BBN.COM Subject: Robert Tappan Morris indicted Date: Thu, 27 Jul 89 10:44:56 -0400

The 7/27/89 Boston Herald reports that Robert T. Morris has been indicted on a single felony count of accessing without authorization at least six (!!) university and military computers. He therefore becomes the first person to be charged under the "Computer Fraud and Abuse act of 1986", a dubious honor at best. If convicted he faces a possible prison sentence of 5 years and a possible $250,000 fine.

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Date: Thu, 20 Jul 89 10:18:58 EDT From: Mark Moraes <moraes@ai.toronto.edu> Subject: Re: UK Defence Software Standard

You precisely underline the risk involved - that the software engineers working on life-critical might not be trained in "modern software engineering".

One does not have to be an academic computer scientist to understand recursion, dynamic memory allocation, multi-tasking, and interrupts. One does not have to be an academic computer scientist to use them, or to decide not to use them.

However, decisions to use or not use such techniques must be informed, and made from knowledge, not ignorance. Turning one's back on new techniques because they are risky in the hands of untrained people is not the answer - training them in the new techniques is.

Yes, training people in software engineering is an expensive business - it also takes time, and is an ongoing process. But if someone involved in RISKy projects is not a top-flight software engineer, isn't that a serious risk to the project? And to the lives that may depend on it?

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Date: Fri, 21 Jul 89 10:03:16 CDT From: Douglas W. Jones <jones@pyrite.cs.uiowa.edu> Subject: Re: UK Defence Software Standard

The terms software engineering and software engineer have clearly gotten completely out of control if people with AA degrees or less are calling themselves software engineers. It is my understanding that the ABET takes a very strong stand on who should be allowed to call themselves an engineer. If I remember correctly, they say that the term should only be applied to those who have one of the following qualifications:

1) People who have passed a state professional engineering examination.

2) People who have graduated from an accredited 4-year engineering program.

3) People who have graduate degrees.

In the past, I have had a fairly negative feeling towards this strict rule. As a professor of computer science in the liberal arts college of a large university, I've always had the feeling that it discriminated against graduates of my program in favor of graduates of similar programs that happen (usually for historical reasons) to be in engineering colleges.

I feel strongly enough about the misapplication of the term software engineer that, if things continue to develop the way they are currently developing, I would even be willing to urge state regulation of the use of the designation.

Consider an analogy: The people who design the power distribution system for a power plant are electrical engineers. They have college degrees in electrical engineering, they are usually fairly senior, and they usually have state professional engineering certificates. The people who build the power distribution system are electricians working under the supervision of an electrical engineer. They may have AA degrees in engineering technology, and they have passed a state or local electricians examination.

I do not object to someone with an AA degree in software technology helping to write the software to control that power plant, but I do object to their billing themselves as a software engineer, and I do object if the power company puts them in charge of the design of such software. This appears to be precisely what is happening today.

Douglas W. Jones, University of Iowa, jones@herky.cs.uiowa.edu

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Date: Fri, 21 Jul 89 11:16:23 CDT From: Douglas W. Jones <jones@pyrite.cs.uiowa.edu> Subject: polling vs. interrupts

I have enjoyed the recent arguments about polling and interrupts that were kindled by the UK defense software standards debate, but I have found them to be incomplete.

I have written real-time software, I have worked on the design of real-time multiprocessors, and this summer, I have even spent far too many hours counting cycles, but I also like interrupts.

When I was involved with the Modcomp User's Group, and again, when I worked for Rockwell International, I met many strong advocates of the view taken by the UK software standards. Most of them were older programmers who hadn't heard of Dijkstra but had years of experience making reasonably complex real-time systems work reasonably well.

Their arguments usually boiled down to the following: When a program is constructed as a single main polling loop and all action routines are called from within this loop, it is easy to assure that the program meets real-time constraints. Each routine called from within the main loop can be given a strict time limit, and it is fairly simple to show that each routine lives within this limit.

Within action routines called from the main polling loop, some fairly simple rules must, of course, be obeyed. Straight-line code is easy to verify, branching code is easy to verify, and definite loops can be verified, but indefinite loops are forbidden.

If you look at typical real-time programs of the 60's and 70's, these rules weren't much trouble. User interfaces were crude at best, and most of the processing was fairly simple feedback control with little algorithmic complexity. Unfortunately, many of the larger problems we face today are far more complex, with significant algorithmic components.

The very coding constraints that allow straightforward verification that a a program meets simple real-time constraints serve to obscure the algorithmic structure of the program. When one or more logical tasks within a real-time program involve complex algorithmic structures, they must usually be recoded using state machines that make a state transition each time they are called from the main polling loop.

As a result, it remains easy to verify that the complex tasks do not consume more than their allotted time slots in the main polling cycle, but that is all. All other aspects of the complex tasks are hidden in a mass of state machines so that even simple questions can take hours to answer. In fact, this structure can even impede the verification that some real-time constraints are met. Consider the problem of verifying the real time behavior of a logical task that, after detecting an event, must respond after a computation that requires multiple iterations of the main loop.

Douglas Jones, University of Iowa, jones@herky.cs.uiowa.edu

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Date: Fri, 21 Jul 89 10:53:53 EDT From: nazgul@apollo.com (Kee Hinckley) Subject: Single Point of Failure for Internet Management

The Boston Globe today (Fri, July 21) reported that the GAA has recommended that an advisory committee be set up to run the Internet since there was "no one as the wheel" in the latest virus incident. It seems to me that this potentially slows down the response time of the Internet to such problems and creates a single point of failure (cut out communication to the committee and now no one knows what to do). -kee

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Date: 20 Jul 89 08:19:00 PDT From: "FIDLER::ESTELL" <estell%fidler.decnet@nwc.navy.mil> Subject: DARPA contract & AI for moving targets

Two points:

1. Many years ago, the single integrated target list was for a war, that included by implication nuclear war. But even in nuclear war, NOT EVERY weapon used will be nuclear. There are some missions where conventional albeit "smart" weapons would really be better. It follows that we - and they - really do need to target things that move; e.g., large ships, and mobile missile launchers.

2. A large ship is almost equivalent in population and technical complexity to a small town; e.g., 5000 "residents" with enough "restaurants" and "movie theaters" to serve them. Recent news item: The USSR is developing for deployment its first aircraft carrier.

The technical points of "how to select" targets are a fertile question for RISKS. If and when we want to debate the policy, maybe we should move that to ARMS-D@XX.LCS.MIT.EDU Bob

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Date: Thu, 20 Jul 89 09:51 MST From: MCCLELLAND_G@CUBLDR.Colorado.EDU Subject: Two-Word Last Names and Other Amusing Database Stories

Two amusing computer-related security stories from the Univ. of Colorado:

1. Bank Card Numbers for Everyone: Continuing Education offers community courses and unlike other units of the university is therefore compelled to accept bank cards for payment. This necessity was overlooked when the new student information system was created so no protected field was allocated to hold bank card numbers and no otherwise unused field appeared to be big enough. But someone cleverly decided to use an unused address field for this purpose until it was discovered that almost anyone with any access to the system could then read a student's name, address, and VISA number.

2. Another Two-Word Last Name Problem: The Colorado Association of Research Libraries now offers an on-line database of citations for every article in every journal any of the libraries receive. It isn't as good as services offered by DIALOG or ISI or other big commercial operations but it is a boon to local researchers. They offer it free to university folks but want to sell the service to outside users. Hence, all faculty now need user ids. They cleverly use SSN and last name and both are displayed when you type them on a public terminal. But mine wouldn't work! I called the CARL office and once I identified myself as a confused faculty member the cheerful clerk gladly told me my proper user id over the phone. [I thought about asking her how she knew I was who I said I was but the risks seem to be all theirs and not mine so I didn't bother.] It turns out one must add the prefix "A9/" to the SSN [maybe they added that for security :-)]. But mine still wouldn't work. Then she discovered that on the university payroll tape that had been used to create the user database my name had been entered as "Mc Clelland" so that forevermore my CARL name would be "Mc". That worked fine.

Gary Mc [Clelland] mcclella@colorado gmcclella@clipr.colorado.edu

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Date: Thu, 29 Jun 89 16:59:48 PDT From: Andrew Klossner <andrew@frip.wv.tek.com> Subject: Credit card issuers invade cardholders' privacy

Excerpted from "The Facts About ... Credit Cards," in the April 1989 issue of "Vis a Vis" magazine, "The Magazine of United Airlines, Inc.":

"Enhancement" is industry parlance for the tie-ins, upgrades, rewards, automatic insurance and warranty protection for products bought with the card. Issuers continuously sweeten the enticements ...

Shopping for clothes? Traveling abroad? Do you prefer bespoke British tailoring? Country inns -- in New England or France? Your card company will soon know a thing or two about your tastes in restaurants and may some day [sic] be a source of recommendations for lodging, dining and a host of other services.

Card companies are investing huge sums of money to read and analyze your charge receipts. The "enhancement wars" create handy perks, but the battle for the hearts and minds of cardholders also rages in computer banks across the country ...

The payoff for issuers who successfully use technology to analyze customer spending will be tremendous, asserts John Love of "Credit Card News." "This information is extremely personal to the customer," he says. "He might begin to feel that his card company really understands him."

Chenault of American Express says his company is "betting the ranch" on its $100 million Genesis Project. The program's goal is to make sure the company's nearly 300 mainframes and minicomputers can create dossiers on the tastes of cardholders. Says Chenault: "If a cardmembers is traveling to Paris, we could develop a personalized itinerary before he even gets there. We'll know his tastes in restaurants, special interests and shopping, and we could work with establishments to arrange even big-ticket purchases."

Sigh.

-=- Andrew Klossner (uunet!tektronix!frip.WV.TEK!andrew) [UUCP] (andrew%frip.wv.tek.com@relay.cs.net) [ARPA]

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Date: Fri, 30 Jun 89 09:39:04 PDT From: Andrew Klossner <andrew@frip.wv.tek.com> Subject: Re: windowless cockpits

"Video and graphics processing is performed, and digitized pictures are relayed to the helmet display."

It's the graphics processing that offers the most promise. Some projects (sorry, I have no references) are investigating the effect on military pilot performance when the visual display is *simplified*, to the point where important objects in the field of view are reduced to wireframe figures, and unimportant objects are eliminated altogether. Thus, an approaching mountain might look like an inverted cone sticking up ahead of you; a river underneath (or civilians about to be bombed) wouldn't be visible at all; and aircraft around you would show as stick figures, perhaps with color coding to convey relative velocity, friend-or-foe evaluation, etc. An approaching missile might look like a line growing toward you, just like it does in the "missile attack" video games.

The win is that humans are better at pattern recognition when the patterns are simple and the distractions are eliminated, especially in time-critical situations. Look at how well we do at those video games.

Another win is that, since the pilot no longer needs visual input besides the (relatively low-bandwidth) wireframe presentation, it becomes that much easier to move the pilot outside the plane, perhaps to a bunker on the ground, and run the plane by remote control. The only important sensory input that would be missing is acceleration (including gravity, "which way is down"), and good pilots learn to distrust that anyway.

But there are still occasions when you need a full-video picture, such as evaluating damage to an enemy aircraft (is it on fire?) or locating an emergency landing site. And simplified video presents new opportunities for defensive counter-measures -- you'd like the enemy's system to classify your fighter as "unimportant," or to classify your chass as "important."

"... the possibility of crashing an airplane because of a failure in the video system, coupled with the inability to look out the window (because the plane doesn't have one) is terrifying."

This risk should be kept in perspective. For example, on a high performance aircraft with forward-swept wings, if the computer handling flight stability goes down, it doesn't much matter whether the pilot can see or not; the plane is going to crash.

-=- Andrew Klossner (uunet!tektronix!frip.WV.TEK!andrew) [UUCP] (andrew%frip.wv.tek.com@relay.cs.net) [ARPA]

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End of RISKS-FORUM Digest 9.8 ************************