Article View: comp.virus
Article #4769On the definition of viruses
From: Fred Cohen
Date: Wed, 06 Jan 1993 03:30
Date: Wed, 06 Jan 1993 03:30
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Computer viruses do not have to be malicious, they do not have to be Trojan horses, and they do not have to enter without the knowledge or consent of the user. Any definition that depends on these properties depends on peoples' opinions, skills, and knowledge, and are thus not "testable" in the scientific sense of the word. (See Popper and others for more details). For example: The "stoned" virus is not apparently malicious - perhaps others do not agree - perhaps this is why we should not make our definition depend on that property (i.e. peoples' opinions). Is it a virus for you but not for me? The "Brain" virus notifies you of its presence with a copyright message displayed whenever you do a directory of an infected disk. It doesn't fit the Trojan horse definition by my understanding if it announces itself. Is it not a virus? If I know I am placing a Jerusalem virus in my computer, is it not a virus? It entered with my knowledge and consent, thus it is not a virus by the third criterion above. Is it a virus for you and not for me? The mathematical definition first published in 1985 is testable, and appears to properly differentiate viruses from non-viruses. Perhaps someone else wishes to do a better job, but let's not make definitions that are senseless. So what is a computer virus? In simple terms, it is a sequence of instructions that, when interpreted in an appropriate environment, "replicates" in that at least one relica also "replicates", etc., ad infinitum. Want an example? A backup program replicates by making an exact copy of itself (if it does a good job) on the backup media. In many environemnts, you can run a program from the backup media (e.g. a remote file system backup). If you run the backup program from the backup media, and it again replicates, etc., ad-infinitum, then it is a virus! Suppose we put the backup program for DOS in an IBM mainframe? in that environment, it would probably not be a virus, because it wouldn't probably operate in the mainframe operating environment. Thus we see the intimate link between a virus and its environment. I don't want to waste more space here, but there is a good deal more to know and think about in applying this definition. On benevolent viruses: If a virus doesn't have to be malicious, perhaps the same technology can be beneficial! When I published this idea in 1984 (in the paper that first described viruses to the scientific community), nobody commented on it, but when I published the results of 7 years of research with benevolent viruses in The Sciences, I was very publicly called a heretic. The loudest complaints came from the academic community! It seems they are not as open minded as they claim to be. They were closely followed by the anti-virus industry, which has been using the press to make money by claiming that all viruses are bad. At least they have well understood motives. I don't so much mind that these people have their opinions, everyone is entitled to that. I do mind when they force their opinions on others - for example, when they tell people to write letters to The Sciences telling them that it is wrong to publish the concept that viruses can be used for good, and when they claim that I am telling people about the possibility of benevolent viruses only to sell a product. If that were true, I wouldn't publish my results, I would only use them for my financial advantage. It is certainly true that the anti-virus vendors (which I am no longer one of) stand to make money by convincing people that all viruses are bad and that they are a major threat. Another upsetting example is the censure at the DPMA, ACM, IEEE Annual Computer Virus and Security Conference held in New York each March. In this conference, they blank out portions of papers and provide full text only to conference attendees. So if I publish details of benevolent virus techniques and how to make them safe, only the attendees will see the details, and the paper will look like swiss cheese. Does the fairness doctrine apply to electronic media? Do the DPMA, IEEE, and ACM have such a lock on research in the computer field in the US that we allow their censorship to prevent us from hearing about ideas that aren't popular? Do the universities support this censorship of ideas? Do they do it for grant money in computer security? (They must be pretty hard up if the grant money in this field is enough to sway them into anything.) Maybe this posting is about a little bit more than just viruses. It seems to me that censorship in all its forms leads to ignorance and all of it's evils. To quote Maxwell Smart: "If only they could have used their power for goodness instead of evil." I am glad that other people who read virus-l don't rule out the possibility of benevolent viruses. I'm sad that so many virus-l readers have been misled about the true meaning of viruses. I'm even sadder that our university people in the US don't think that new and different ideas are good and decide to try to censure them. I'm really glad that I no longer sell virus defenses, because I think it's a pretty shady business (except for a few good companies that tell the truth about viruses and their products).
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Path: arc1-ca.pugleaf.net!sparky!uunet!dtix!darwin.sura.net!jvnc.net!netnews.upenn.edu!netnews.cc.lehigh.edu!news From: fc@turing.duq.edu (Fred Cohen) Newsgroups: comp.virus Subject: On the definition of viruses Message-ID: <0020.9301062041.AA14693@barnabas.cert.org> Date: 6 Jan 93 03:30:03 GMT Sender: virus-l@lehigh.edu Lines: 99 Approved: news@netnews.cc.lehigh.edu