It has now been more than a year since the ACM Council passed its resolution on computer systems and risks to the public. Quoting from RISKS-1.1: The second part of the resolution includes a list of technical questions that should be answered about each computer system. This part states that: While it is not possible to eliminate computer-based systems failure entirely, we believe that it is possible to reduce risks to the public to reasonable levels. To do so, system developers must better recognize and address the issues of reliability. The public has the right to require that systems are installed only after proper steps have been taken to assure reasonable levels of reliability. The issues and questions concerning reliability that must be addressed include: 1. What risks and questions concerning reliability are involved when the computer system fails? 2. What is the reasonable and practical level of reliability to require of the system, and does the system meet this level? 3. What techniques were used to estimate and verify the level of reliability? 4. Were the estimators and verifiers independent of each other and of those with vested interests in the system? In the intervening year, I am not aware that the developers of ANY computer system have made public their answers to these four questions. Readers of this forum will surely not leap to the conclusion that no computer system presents risks to the public worthy of discussion. I would like to start a discussion on how we can change this. What can we do as professionals to make it the norm for system developers to present risk assessments to the public? * What can we do to make it more attractive to present a risk assessment? - Explicitly invite developers of particular systems to publish draft assessments here in the RISKS Forum, with the promise of constructive feedback. - Inaugurate a section in CACM for the publication of refined risk assessments of systems of great public interest or importance. - Publish the risk assessments without refereeing. This gives the developers "first shot," gets the material out more quickly, and lowers the barrier to publication, without limiting the opportunity for public discussion and debate. - Encourage developers to also address John McCarthy's question: 5. What are the risks inherent in the best available alternative to the system in question? - Encourage the exploration of legal steps that would make Risk Assessments as routine as Environmental Impact Statements. (This could be useful even if most of the former are as pro forma and unenlightening as most of the latter; they provide a starting point.) * What can we do to make it less attractive not to present a risk assessment? - First, make it very clear that we, as a profession, believe that it is incumbent on system developers to present their risk assessments, and that delay or refusal amounts to malpractice of a very high order. - Periodically publish (and publicize) the status of all outstanding invitations to present risk assessments. - Bring cases of persistent noncompliance to the attention of ACM Council for appropriate action. I present these suggestions as a springboard for discussion, not as a definitive program for action. I welcome suggestions for improvement. Jim H.
To: RISKS@SRI-CSL.ARPA cc: Horning@DECWRL.DEC.COM Perhaps we can learn something from some steps that have been taken by the National Computer Security Center (although for security and not reliability). The NCSC (formerly the DoD CSC) has established a set of criteria for trusted computer systems, in the form of a range of increasingly stringent requirements. They have evaluated various systems against those criteria. They have also explored what kinds of applications should have which requirements. To date, two systems have been accorded high rankings: (1) the highest existing rating [A1] to the Honeywell SCOMP -- whose kernel design and trusted subsystems have undergone formal design proofs demonstrating that the kernel specifications satisfy a security condition of no adverse flow, and that the trusted subsystems satisfy other relevant properties involving privilege, integrity, and functional correctness; (2) a somewhat lower rating [B2] to Multics, which has not been subjected to any formal analysis, but which satisfies certain of the hardware and software-engineering criteria and which has withstood extensive penetration attacks. Other systems have also been evaluated, but given lesser ratings — implying greater potential security risks. (The NCSC also publishes an Evaluated Products List.) The literature on this subject is extensive, but I note a few items here on the Criteria and on the SCOMP proofs. Other than that, you can look at the IEEE Proceedings for the Security and Privacy conferences each April and the National Computer Security Conferences held at NBS roughly once a year (previously called the DoD/NBS Computer Security Conference). I of course need to add that the work on secure and trusted computing systems is only a very small part of that addressing the potential "risks to the public", which of course also involve reliability in various forms, human safety, timely responsiveness, etc. But my point is that some steps in the right direction are actually being taken in the security community -- although those are still only small steps with respect to the overall problem. Nevertheless, something can be learned from the security work in addressing the ACM goals that Jim has reminded us of once again. So, let us try to address some of Jim's points specifically in the future. REFERENCES: CRITERIA: Department of Defense Trusted Computer System Evaluation Criteria, CSC-STD-001-83. Write to Sheila Brand, National Computer Security Center, Ft Geo G Meade MD 20755. (SBrand@MIT-Multics) SCOMP KERNEL DESIGN PROOFS: J.M. Silverman, Reflections on the Verification of the Security of an Operating System, Proceedings of the 9th ACM Symposium on Operating Systems Principles, October 1983, pp. 143-154. SCOMP TRUSTED SUBSYSTEM DESIGN PROOFS: T.C.V. Benzel and D.A. Tavilla, Trusted Software Verification: A Case Study, Proceedings of the 1985 Symposium on Security and Privacy, IEEE Computer Society, Oakland CA, April 1985, pp. 14-31. (Note: In a proof of design consistency, the proof must show that a formal specification satisfies a set of requirements, e.g., for security or fault tolerance. The difference between requirements and specifications in that case is generally that the former tend to be simply-stated global properties, while the latter tend to be detailed sets of constraints defined [e.g.,] functionally on state transitions or algebraically on inputs and outputs.) ---------------------------------------------------------------------- Date: Tue, 8 Oct 85 16:26 EST From: Jan Lee <janlee%vpi.csnet@CSNET-RELAY.ARPA> To: RISKS@sri-csl.arpa Subject: The Titanic Effect THE TITANIC EFFECT (Source unknown): The severity with which a system fails is directly proportional to the intensity of the designer's belief that it cannot. COROLLARY: The quantity and quality of built-in redundancy is directly proportional to the degree of concern about failure. JAN ---------------------------------------------------------------------- Date: Wed, 9 Oct 85 09:43:20 EDT From: Brian_Borchers%RPI-MTS.Mailnet@MIT-MULTICS.ARPA To: firstname.lastname@example.org Subject: Databases, Grades, etc. Here at RPI, The Registrar's database, as well as the Bursar's systems are on the same machine that we use for academic work. We've put a lot of effort into making MTS secure... [By the way, some of this issue's discussions on the low risks of putting grades on student computers reflect overall a benevolent naivete about the system security risks. I have not tried to comment on each message individually, but find them intriguing. One could turn the students loose to see how many flaws they can find, perhaps as a part of a course: give them all F's in the database, and let them try to earn their A's by breaking in! On the other hand, you might find the last one who breaks changes some of the A's to F's! It is dangerous to announce in public that you as an administrator believe you have made unauthorized alterations difficult or impossible; knowing how badly flawed most of the systems are, that is a very large red flag to wave. But then you apparently need to be shown that you are wrong. Audit trails are great too, but watch out for the penetrated superuser interface. (This comment only touches the tip of the iceberg. Judging from this issue's contributions, I imagine the discussion might run for a while. Let's get down to specific cases if we can, but not just students' grades — which are only an illustrative problem.) PGN]
Hal Murray in RISKS-1.20 asks whether any schools are "brave/stupid enough" to have students and grades on the same computer. Well, that is the situation here. Administrators and students use the same mainframe. Administrative here generally use several extra layers of security such as extra passwords, allowing sign-ons to certain accounts only from specific terminals, and logging all successful and unsuccessful sign-ons to our accounts. So far, we in the Registrar's Office have not detected any unauthorized sign-ons (and we have never noticed any strange changes to files) although we occasionally detect an unsuccessful sign-on attempt from an unauthorized location. Generally, changing passwords frequently and using non-words and special characters for passwords seems to take care of the unauthorized access problem. One thing that Hal did not mention is security problems when students and grades are on separate computers but on the same network, perhaps to share a special device or certain files. It seems to me that there could be almost as many potential security problems with this configuration as with my configuration. Does anyone have experience with this type of configuration and if so, what problems have you had?
To: risks@SRI-CSL.ARPA I tend to think that stories about crackers changing their grades should be taken with a fairly large dose of salt. I once had the occasion to interview a vice-chancellor at my undergraduate university, and he explained the system there in some detail. Basically, they handled grades the way a bank handles money — that is to say, there were 'audit trails' and paper copies of everything. Discrepancies between what was in the computer and what was in the paper records would eventually get caught, even if there was a period of time when the wrong grades would show up on an official transcript. Correctly faking ALL the records so as to escape an audit would have required a great deal of knowledge (basically, it would have to be an inside job — and they didn't have students working in these offices). --Mark
To: MDAY@MIT-XX.ARPA cc: Neumann@SRI-CSL.ARPA Mark, I find myself disbelieving some of what you say. Manual comparisons tend to get done (if at all) when the data is entered. Auditing tends to get slighted, since people often tend to assume the computer is right! (The Santa Clara inmate who changed his release date did get caught, but perhaps only because a guard overheard him bragging about how he was going to get out early.) Most vice-chancellors (and many administrators) would probably tell you they are doing things right, and better than everyone else. That is the head-in-the-sand view of computing — everything is just fine. But audit trails and paper copies of everything are not sufficient, even if they are diligently used. "Discrepancies ... would eventually get caught" is certainly hopeful, at best. Peter
To: Neumann@SRI-CSL.ARPA Peter, I still maintain that the scenario of "student changes grades to A's and lives happily ever after" seems dubious. It seems to be one of these apocryphal stories where everyone knows about someone who's done it, but there's little evidence floating around about it (sort of like stories about people putting cats in microwave ovens to dry them). Your other comments are well-taken. It certainly requires administrators, etc., to have a perception of the problem; that was one reason I was impressed by my interview with the vice-chancellor. Several years ago, crackers were not yet in the public eye, so I was pleasantly surprised to find out that anyone cared about the overall integrity of the grades database and talked about the need to regularly audit it. --Mark
The University I attended had its database on a computer that student courses used. However, it was (is) a very well-kept secret. It is hard (under the OS of this system) to find out what people *might* log on. Also, it seems that hacker-types don't get the work-study jobs in the registrar's office. I'm not sure how long they can keep it up, but it's worked well for at least 5 years. (I only found out because I got to be good friends with the facilities people, and one of them happened to mention it.) I guess this just reinforces the belief that human beings can make a risky or less-risky depending on how they use it. --Alan Wexelblat WEX@MCC.ARPA ------------------------------ Date: Wed, 09 Oct 85 16:12:15 EDT From: Ross McKenrick <CRMCK%BROWNVM.BITNET@WISCVM.ARPA> To: RISKS@SRI-CSL.ARPA Subject: Databases, Grades, etc. Students and grades can exist on the same machine. Attempting to partition the students' and administrations' computing environments is a crude form of security which eliminates the possibility of providing students online services such as class lists and registration changes. We take a two-fold approach to database security at Brown University: 1) prevention and 2) detection. We minimize our window of vulnerability by making it nearly impossible to gain unauthorized access to the programs which update grades, etc, and by making it nearly impossible to change a grade (even when authorized) without generating audit records, security log entries, and notifications slips for the professor. We are not dealing with an EFT-type environment where "smash-and-grab" might work. A student is at Brown for four years, and his/her transcript is maintained by the Registrar forever. A student could theoretically change his/her grade for a day or two *in the computer database* (which does not mean that the grade, which is intangible, was actually changed). However, a system of checks and balances, built into and outside of the computer system, would eventually result in discovery, correction, and punishment. Suppose I could design a security system which was 90% (OK, 80%) secure. Then, rather than spend more time making it more secure (point of diminishing returns), I could spend my time on a recording/ reporting system which was 80% secure. Now, I finish by dovetailing the two systems to make it very unlikely that a hacker could survive both levels. Meanwhile, the Registrar, who is rightfully suspicious of computer security anyway, devises manual checks and balances which adds another level of security beyond the computer entirely. Wouldn't it simply be easier for the hacker to forge a grade change slip from his/her professor? Now, considering all of this, you've got certain expulsion and prosecution under Rhode Island State Law hanging over your head. Why would someone who's got all of this figured out have trouble passing courses, anyway? A collegue of mine likens a malicious hacker in a fairly-well-secured computer environment to a bull in a china shop. The china is replaceable, the bull is dead meat. Now comes the auto-theft-prevention-device philosophy: why pick on a fairly-well-secured environment when there are so many unsecured environments to fool with? Security in computer-recordkeeping is a very serious subject. But you must keep it in perspective with the alternatives: manual record- keeping, locked doors and desks, etc.
To: RISKS@SRI-CSL.ARPA Regarding the subject of the risks of computer technology (in general) and large databases (FBI's NCIC, TRW, NSA, tenant/landlord database in California, and the Census), there is a reporter from the New York Times who has done quite a bit of research into it. His name is David Burnham, and his results a few years back are published in his book "The Rise of the Computer State" (paper/hardback). The book is a call to arms to the millions who don't realize the serious threat to our freedom that this poses. Its shortcoming, as such, is that it is mostly a quite comprehensive series of anecdotal reports on various errors and abuses (incorrect warrants, Nixon abuse of phone company records, abuse by politicians, etc) of large informations stores. However, if you need convincing that this is a problem, you will find it in this book. Burnham spoke here this past Tuesday and updated his list of "horror stories", as he puts it. One number he gave, if my notes are right, is that an FBI audit of their NCIC showed that ~10% of the warrants proposed by this system are somehow based on incomplete or invalid information. He also mentioned proposals to increase the NCIC to include a White Collar Crime Index that would specifically contain the names of SUPPOSED white collar criminals and their ASSOCIATES. As Burnham pointed out, if they can't maintain the actual criminal information properly, what are the consequences when they start accumulating hearsay and gossip? A serious problem is that no one has a real interest in keeping this information very correct, except for the falsely accused citizen, and, as Burnham pointed out, he doesn't have any way to correct it. I also agree quite heartily with Matt Bishop that "the greatest risk is not from the technological end but the human end." The technology itself is not to blame, but we need, especially as computer professionals whose opinions in the matter would be seriously regarded, to recognize the growing threat to our liberties and to act accordingly. Randy Parker MIT AI Lab PARKER@MIT-REAGAN
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