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RISKS-LIST: RISKS-FORUM Digest Monday 21 March 1988 Volume 6 : Issue 47

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

Contents: NTP Timewarp - the difficulties of synchronizing clocks (Jerry Leichter) USA: Time for wrong time, again (Scot E. Wilcoxon) Risks from smart terminals - and risks that aren't there (Jerry Leichter) ATMs and Fear of Cameras (Jeff Stearns) More Communications Insecurity (Dennis Hamilton) What the computer says, goes - even if it is obviously wrong. (Michael Newbery) Risks of automatic mailwatch reply programs (Martin Minow) Census data availability (Joe Morris) Cyber Foundation BBS (James Jones via Martin Minow)

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. 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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Date: Mon, 21 Mar 88 11:37 EST From: "Jerry Leichter (LEICHTER-JERRY@CS.YALE.EDU)"<LEICHTER@Venus.YCC.Yale.Edu> Subject: "NTP Timewarp - the difficulties of synchronizing clocks"

The following message was posted to the tcp-ip newsgroup by Mills@UDEL.EDU.

Folks,

At the moment both the ISI and NCAR radio clocks have failed, while the UDel radio clock is down for repair. This leaves only the UMd and Ford radio clocks online. Unfortunately, sometime since Friday evening the NTP primary time-server network, which usually thrives when one or more radio clocks fail, went nuts and may have delivered bogus time. I believe I have found and fixed the bug, which turned out to be subtle indeed and bit only in an interesting and unusual scenario involving broken spanning trees. As of now (Saturday afternoon) all primary servers ISI, NCAR, UDel, UMd, Ford and DECWRL have been fixed. Note that all except UMd and Ford are running at stratum two, since they have automatically resynchronized to the remaining radio clocks. Secondary servers at Linkabit and Rice, now operating at their usual stratum two, have also been fixed.

There is at least one Unix site that crashed due the broken time. Since the bug was due to my own error and not due to the protocol design or Mike Petry's NTP daemon, I do apologize for any inconvenience. When a new NTP daemon conforming to the latest protocol revision becomes available, even this latest bug will not cause timewarps, should something like it ever happen again.

Dave

I don't know anything about the details of the system involved, but it's nevertheless interesting to compare the description with some of the scenarios Perrow describes in "Necessary Risks". Here we have an apparently highly redundant system (6 primary servers). However, we find a time when two have failed, just as a third goes down for repair. (The numbers don't add up - DECWRL is unaccounted for. Perhaps its network connection failed.) At just that time, a bug is triggered by yet another unusual confluence of events that leaves the network in a particular state. -- Jerry

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Date: Sun, 20 Mar 88 23:02:54 CST From: sewilco@datapg.mn.org (Scot E. Wilcoxon) Subject: USA: Time for wrong time, again

A few types of computers had problems with 1988 or leap year. Next, many USA computer sites get to encounter Daylight Savings time.

This year Daylight Savings time begins on April 3, three weeks earlier than it formerly began. Computers which automatically calculate DST may have outdated programming. Most systems will not actually malfunction, but users of the machines will not consider the old time as being correct.

Systems with time-sensitive interactions with other systems might have problems. Perhaps we'll find out if they're not corrected in time.

Scot E. Wilcoxon, Data Progress {amdahl|hpda}!bungia!datapg!sewilco +1 612-825-2607 [Pun unintended? PGN]

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Date: Fri, 18 Mar 88 13:01 EST From: "Jerry Leichter (LEICHTER-JERRY@CS.YALE.EDU)" <LEICHTER@Venus.YCC.Yale.Edu> Subject: Risks from smart terminals - and risks that aren't there

The recent discussion of the various risks posed by smart terminals has in- evitably lead to a comment (Jim Frost's) about VT220's. Actually, VT220's and related terminals are examples of the RIGHT way to design smart terminals for a hostile environment:

a) It is indeed possible to send a request to a VT220 and have it reply with its programmed answerback sequence - which could be anything at all. However, the answerback sequence cannot be changed by anything the host sends - the only way to get write access to it is from local setup mode.

BTW, this should again emphasize that if you don't have adequate physical control over your equipment, all bets are off.

b) It is possible to program some of the keys on a VT220 and have it send anything you like when that key is struck. Unlike the answerback sequence, key definitions CAN be changed from the host. However, it's possible to lock the key definitions. Once they are locked, nothing the host does can unlock them; the lock bit can only be cleared locally, from setup mode.

I should also point out that the programmable keys are all inactive until you load something into them - it's not possible to change, say, RETURN to "DELETE". This makes it unlikely that you can catch someone who never loads the programmable keys, and hence leaves them unlocked.

c) It's possible to lock the keyboard from the host, but it's also always possible to go into setup and unlock it. In addition, a user can locally "lock user preference features", which disables the host's ability to modify some terminal para- meters. "Keyboard Action", which is the parameter that con- trols whether the keyboard is locked or not, is a user pre- ference feature.

There may be ways to "hack" a VT220 - actually, there are probably more ways with its graphics cousin, the VT240. My point here is not that there are NO risks with a VT220; it's that it IS possible to design a smart terminal that does a pretty good job of avoiding most of them. Just because some terminal interfaces are poorly thought out doesn't mean that it's impossible to design good ones. -- Jerry

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Date: Thu, 17 Mar 88 11:15:05 PST From: jeff@tc.fluke.com (Jeff Stearns) Subject: ATMs and Fear of Cameras (Re: RISKS-6.41) Organization: John Fluke Mfg. Co., Inc., Everett, WA

ATMs aren't protected by cameras. They're protected by the *fear* of cameras.

Banks rely on that fear. But that's risky for them, too.

I always treated cash machines with reasonable respect until I once had to amuse myself while waiting for the machine to complete a particularly sluggish transaction. Growing tired of mugging for the camera, I paused to inspect it more closely.

The camera was mounted behind a semi-silvered mirror (but we fans of "one way" mirrors always regard them as more of a challenge than deterrent). By assuming a proper viewing position about two inches from the mirror, I could closely study the camera and lens.

The big juicy lens was clearly visible and boldly emblazoned with the single word "Polaroid". The only other distinguishing mark was the corner of a fragment of sticky foam tape which affixed the lens to the "camera body".

From that moment onward, the camera and I became fast friends. I took particular pleasure in asking the bank tellers about its health. In fact, I believe that I was first to alert them when the adhesive dried out and the lens fell off.

Next time you do business with Capital Savings, be sure to smile for the camera. Now I've begun to wonder about the cameras mounted *inside* the bank.

Jeff Stearns John Fluke Mfg. Co, Inc. (206) 356-5064

"Oh, no sir, the cash machine only gave me $20 instead of $40. Just check your camera records; you'll clearly see that only $20 came out."

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Date: Thu, 17 Mar 88 17:11:41 EST From: rochester!cci632!sjfc!deh0654@rutgers.edu (Dennis Hamilton) Subject: More Communications Insecurity

%A Alan Baley %T Tailgating: A dirty little network security problem %J Data Communications %V 17 %N 3 %D March, 1988 %P 55-58 %O Newsfront Section %K Open Connections Unrecognized Disconnects Concentrators Gateways %X This article basically confirms that tailgating is still a regular problem on VANs, private networks, and, of course, your friendly neighborhood university dial-up system. Tailgating refers to the situation where a concentrator or other front-end equipment fails to noticed a dropped call, allowing a new call to seize that slot and operate in continuation of the previous user's session. The article describes how many occurences are a result of careless strapping and configuration of modems and concentrators, but that systems remain vulnerable to the problem, especially when they are overloaded. (When I tried my hand at PC bulletin-board software, this is one of the things that I was proud of getting right. It is very important to *never* let a modem answer on its own, getting the computer to notice and handle the new ring instead. However, many larger systems are not able to operate that way and must use auto-answer modems. It is very easy for a disconnect and new call to go unnoticed under those conditions, leaving the previous caller's accounts and data open to intrusion. It shouldn't be allowed.) [Dennis E. Hamilton: 88-03-17]

%T NASA Encounters a Trojan Horse %J Data Communications %V 17 %N 3 %D March, 1988 %P 83 %O Advertisement %K Digital Pathways West German hackers NASA X.25 intrusion %X This advertisement is for a family of dial-up security products. It claims that the West German hackers who broke into the NASA X.25 (SPAN?) network did so via a Trojan horse and were able to operate unnoticed for three months. The ad suggests that NASA had comprehensive security measures and they were vulnerable anyhow. It is not at all clear to me how network security at access points is any use at all against a Trojan horse, so there seems to be some hyperbole here. It makes for a nice advertisement illustration, though, with a Trojan Horse on the moon in the background behind a LEM labelled X.25! On the other hand, if this is the level of sophistication of the advertiser, would you let them do your network security? Digital Pathways, Inc., 201 Ravendale Drive, Mountain View CA 94043. [Dennis E. Hamilton: 88-03-17] -- orcmid {uucp: ... !rochester!sjfc!deh0654 ...

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Date: 20 Mar 88 21:20:35 GMT From: newbery@comp.vuw.ac.nz (Michael Newbery) Subject: What the computer says, goes - even if it is obviously wrong. Organization: Computing Serv. Ctr, Victoria Uni., Wellington, New Zealand

Another example of "If the computer says it is so, it must be so!"

From the Wellington 'Evening Post', Saturday 19 March 1988, By Karina Barrymore Reprinted WITHOUT permission

Discovery yesterday of a computer error which overcharged interest on some credit cards may have never come to light except for persistent inquiries by a cardholder. An article in the Post last night said Charge Card Corpororation, the manager of 20 retail outlet credit cards [in NZ] had been overcharging interest. After a two week inquiry, [the] managing director finally told the cardholder a mistake had been made-the computer program that calculated the interest was wrong. The company has said it will correct the error and refund all overcharging.

However, the company's attempted fob-off and run-around given to this reporter, who is also the cardholder concerned, is a story on its own. My latest statement showed interest of $9.97 on an opening balance of $111.49 debt. The statement clearly said monthly interest was calculated at 2.46% a month. Out came the calculator and the card's conditions of use and what resulted was total confusion. It just didn't add up.

The next day I rang the co. and spoke to [someone] in the cardholder services dept [who sent a letter] detailing account transactions and the formula for interest calculations. Again the calculator and again it just didn't add up. I rang again and was told I probably didn't understand such a complicated matter and was assured it was right. I responded that I did understand but did not agree with the amount of interest. [The services rep.] finally offered to personally go through the statement and manually calculate the interest, adding: "When we do that we always come up with something different to what the computer tells us."

Why was that?

"I don't know, it always happens. I think it's something to do with the way it's programmed."

[On hearing this the reporter asked to speak with the manager and was refused. After much obstruction she finally reached him.]

He was aware of my inquiry and said the accounts department had credited $5.97 against the interest of $9.97. There appeared to have been an error, he said. He would not say what caused the error. When I repeated the comments made about the computer program he said he would look into it and give me an answer as soon as possible.

Several days and many unanswered messages later I rang the manager again. He had not looked into the problem any further. He thought I would forget about it, he said. He also said he could, if he wanted, redebit the $5.97 credit to my account. On being asked why he would do this he said according to the computer that was the correct amount.

I repeated my request for the matter to be investigated.

Two days later he phoned and said there was an error in the computer program. Interest had been charged incorrectly. "There has been a mistake, an unintentional mistake. We will take immediate steps to rectify the situation." he said.

Michael Newbery

Internet: newbery@comp.vuw.ac.nz

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From: minow%thundr.DEC@decwrl.dec.com (Martin Minow THUNDR::MINOW ML3-5/U26 223-9922) Date: 21 Mar 88 12:37 Subject: Risks of automatic mailwatch reply programs

While I was on vacation last week, broiling under the mind-numbing sun of Southern California and longing for the cool breezes of a late New England winter, I left a "mail watch" program running on my office system. When mail arrived, it formatted a "I'll be out until Monday" response and sent it back to the responder.

A few risks -- some humorous, some not:

1. although the program is supposed to send only one response to an individual, it assumes that all name/node strings are different. This means that a few people who send mailing lists from different machines or via different network paths got extra responses. They were not always amused.

2. Within my company, many Usenet news groups are distributed by a mailer. This means that I receive a few daily messages from "NODE::USENET". My watcher dutifully replied. This triggered a mail watcher on NODE::USENET which patiently explained to my mail watcher how to subscribe to the service. Fortunately, the history file prevented this from escalating to a fullscale network war.

3. I received a query from someone wondering why my mail watcher sent him a reply. It turned out that he had taken some software from an internal library/archive system that mails me a registration notice (good for monitoring bugs and waving at my boss at salary review time).

4. Ken Laws (who distributes the AI-digest) was kind enough to note a more serious risk of such programs: by broadcasting a message that says "I'm out of town until March 20th" to anyone who sends me mail, it's easy for a thief to schedule my house for burglary. Ken noted that one of the lists that discusses stereo equipment experienced some trouble along that line. Martin

[Same thing goes for FINGER/PLAN/... data. PGN]

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Date: Mon, 21 Mar 88 09:13:40 EST From: Joe Morris (jcmorris@mitre.arpa) Subject: Census data availability Organization: The MITRE Corp., Washington, D.C.

The recent postings concerning the integrity of the Federal Archives reminds me of a report I saw a couple of years ago which claimed that there are only two computers in existence which can read the 1960 Federal Census master data tapes. One is in Japan, and the other is in the Smithsonian's collection. I don't know for sure, but I think that the machine used was a UNIVAC II, which would be consistent with the absence of any UniServo-compatible drives for current machines.

The point being made in the article (in Spectrum, I think) was that using new technology is often desirable (or even necessary), but that a blind reliance on that technology may leave you with unusable files if the technology to use them becomes obsolete.

How many RISKS-readers work in shops which have long since removed the last 7-track tape drive? OK, how many of you with hands up still have some users' tapes in your library which were recorded on a 7-track drive? How about historical usage data tapes for the computer center itself? (*blush*)

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Date: 20 Mar 88 19:40 From: minow%thundr.DEC@decwrl.dec.com (Martin Minow THUNDR::MINOW ML3-5/U26 223-9922) Subject: I really don't believe this one -- Cyber Foundation BBS [jejones]

from TELECOM Digest Thursday, March 17, 1988 9:56PM Volume 8, Issue 52

From: <atari!sun!mcrware!jejones@ames.arc.nasa.gov> Subject: Cyber Foundation BBS Date: 16 Mar 88 23:08:53 CST (Wed)

I've just read something in the "Computer Communications" column of the April 1988 *Computer Shopper* that I find HIGHLY disturbing and which I think should be brought to the attention of modem users. I quote the salient portion:

"In a recent issue of *Info-Mat* magazine, an online 'magazine' available on 170 selected BBSs across the country, it was reported that the feds have underwritten a BBS to monitor the BBS user community, with an eye toward taxation and regulation. The Cyber Foundation BBS describes itself and its system in a text file as 'a non-profit government-supported system run by the United States Instructional Department. [has anyone ever heard of this alleged organization?] This system is a test for the government and FCC to determine if bulletin board systems, non-paying information exchange systems, should be charged for use.'

"The sysop of the Cyber Foundation BBS is Chris Regan, who has left messages to the effect that he does not work for the government, but that the govern- ment has paid for (part of?) the equipment and operating costs. An elaboration of the system's purpose as stated by sysop Regan in some online messages is, 'a test to see if bulletin boards, their phone lines, and others, should be taxed or have a tariff placed on the information.'

"Other regulatory ideas discussed on the BBS by the sysop have included the licensing of modems (similar to ham radio), and the licensing of BBSs, inclu- ding the segregation of BBSs by computer type, and foregoing any semblance of BBS privacy by giving a government official the right to log on and 'inspect' all messages and files at random times.

"There is little justification for regulating computer communication via telephone. As a licensed ham radio operator, I understand the reasons why transmission of voice or data over the radio spectrum are regulated, but none of these reasons are applicable concerning telephone usage. When I make a call on my telephone, whether I communicate by voice or computer, it is a private matter between the party I am calling and me. The government has no more business pursuing private messages I have left on a BBS than they do voice messages I leave on a friend's answering machine. The FCC has spent the last several years reducing regulation on the radio services; there is absolutely no reason for them to set up a whole new area of regulation in the telephone service.

"These ideas for bureaucratic power grabbing, invasion of privacy, limitation of free speech and government money grubbing need to be refuted before they advance any further. The Cyber Foundation BBS is located somewhere in Connecticut and the phone number is (203) 264-5463. I encourage you to call it up and let your opinions be known (courteously, of course)."

[end quote]

I have called the phone number, and found a BBS that does indeed go by that name, with the stated Chris Regan as sysop. Those messages I looked at didn't seem to discuss the issues mentioned in the *CS* article; however, any threat to the Constitution merits investigation. (I left a message with the sysop expressing my concern.) Does anyone out there know anything about this BBS? Are the cited issues really under discussion there? Thanks... James Jones

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