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- åIntroduction
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- Viruses and other kinds of destructive computer software have become an
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- increasingly serious problem in the computing world. In the Macintosh
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- community, although the problem is not as serious as it was several
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- years ago, viruses continue to spread rapidly and widely. Viruses will
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- continue to cause problems for some time.
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- A virus is a piece of software which attaches itself to other programs or
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- files. Viruses quickly propagate to other files and disks as you use your
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- computer. Viruses spread from one Macintosh to another via the sharing
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- and distribution of infected software or infected disks. This sharing can
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- be through the Internet, exchanged floppies or file servers on a local area
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- network.
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- Viruses may be malicious or non-malicious. Non-malicious viruses
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- replicate, but they do not attempt to do anything destructive. For
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- example, they may beep, display messages on the screen, or do something
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- else innocuous, but they do not intentionally try to do any damage. On the
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- other hand, malicious viruses, in addition to replicating, do attempt to
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- damage something. For example, malicious viruses often intentionally
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- damage or delete files or destroy the contents of hard drives.
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- We are very fortunate that to date most of the known Macintosh viruses
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- are non-malicious. It is very important to realize, however, that even
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- non-malicious viruses are always damaging, even if the damage is
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- unintentional. Many people who have experienced infections have reported
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- problems with the normal operation of their Macintosh. Viruses occupy
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- memory and disk space and this is enough to cause problems all by itself.
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- They also live at very low levels in the operating system and can
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- interfere in unexpected ways with other parts of the system. We have
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- also discovered errors in most viruses which can cause unexplained
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- crashes and strange behavior.
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- VirusScan recognizes all of the currently known Macintosh system
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- viruses. It also recognizes all the known variations and clones of these
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- viruses. Furthermore, VirusScan also recognizes many possible unknown
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- variations and clones. It will both detect the viruses and, when possible,
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- repair files which have been infected by the viruses.
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- VirusScan will not recognize all possible viruses: only the ones it has been
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- configured and programmed to recognize. If a new virus or strain
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- appears, we will have to modify the program to recognize it, and you will
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- have to get a new copy of the program.
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- VirusScan does not recognize application-specific scripting or macro
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- language viruses. These include the “Dukakis,” “Three Tunes,” and
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- “MerryXMas” HyperCard viruses and the Word 6 macro virus.
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- VirusScan also includes a virus protection extension (VirusScan
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- Extension). When properly installed, the VirusScan Extension will protect
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- an uninfected system against infection by any of the known Mac system
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- viruses.
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- Viruses should not be confused with other types of destructive software
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- such as “worms” and “Trojan horses.”
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- A “worm” is a program which replicates and spreads, but does not attach
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- itself to other programs. Unlike a virus, it does not require a host to
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- survive and replicate. Worms usually propagate over a network of
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- computers. They are not spread through the sharing of software or disks.
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- The most well-known example is the Fall 1988 Internet worm, which
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- infected and disabled several thousand government and university UNIX
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- computers in a single day.
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- A “Trojan horse” is a program which appears to do something useful, yet
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- additionally does something destructive behind your back. An example
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- would be game or other program which quietly erased your hard drive in
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- the background while you used the program. Trojan horses do not
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- replicate.
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- VirusScan does not attempt to address the problems of worms and Trojan
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- horses.
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- There is no need to panic over the current virus situation. However, you
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- should take the problem seriously. Using VirusScan, it only takes a few
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- minutes per week to effectively protect your Macintosh against the known
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- viruses. See the section titled “Recommendations” for a short list of the
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- simple things we suggest you do to protect your Mac.
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- There is a misconception that you can protect your Macintosh against
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- viruses by merely avoiding shareware and freeware software. This is far
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- from the truth. There have been many reported cases of (inadvertently)
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- infected commercial software, while most of the major national sources
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- of freeware and shareware software are remarkably virus-free.
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- The analogy between biological viruses and computer viruses is striking.
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- Both of them replicate and they both require the assistance of a host to
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- survive. In both cases, the infected system is sometimes severely
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- damaged. With both kinds of viruses, it is sometimes possible to remove
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- the infection without damaging the system and it is sometimes possible to
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- inoculate or vaccinate the system to protect it against future infection.
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- As with all analogies, however, it is possible to carry the analogy
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- between biological and computer viruses too far. Computers are not living
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- organisms. Biological viruses usually occur naturally and are almost
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- never created by people. Computer viruses are always created by people;
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- they never occur naturally. Most importantly, it is not possible to
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- compare the enormous suffering caused by biological viruses such as HIV
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- to the comparatively meaningless damage caused by computer viruses.
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- VirusScan is distributed electronically. When a new virus is discovered,
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- we usually release a new version of VirusScan to recognize the virus
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- within a few days. The official FTP site is:
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- ftp://ftp.mcafee.com
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- Notice of new versions are often posted on CompuServe and America
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- Online.
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