MacWorld 1997 November/Macworld (1997-11).dmg/System Utilities/Disinfectant/Disinfectant.rsrc/STR#_201.txt

Text File | 1997-07-09 | 7.7 KB | 297 lines







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åIntroduction





Viruses and other kinds of destructive computer software have become an

increasingly serious problem in the computing world. In the Macintosh

community, although the problem is not as serious as it was several

years ago, viruses continue to spread rapidly and widely. Viruses will

continue to cause problems for some time.



A virus is a piece of software which attaches itself to other programs or

files. Viruses quickly propagate to other files and disks as you use your

computer. Viruses spread from one Macintosh to another via the sharing

and distribution of infected software or infected disks.



Viruses may be malicious or non-malicious. Non-malicious viruses

replicate, but they do not attempt to do anything destructive. For

example, they may beep, display messages on the screen, or do something

else innocuous, but they do not intentionally try to do any damage. On the

other hand, malicious viruses, in addition to replicating, do attempt to

damage something. For example, malicious viruses often intentionally

damage or delete files or destroy the contents of hard drives.



We are very fortunate that to date most of the known Macintosh viruses

are non-malicious. It is very important to realize, however, that even

non-malicious viruses are always damaging, even if the damage is

unintentional. Many people who have experienced infections have reported

problems with the normal operation of their Macintosh. Viruses occupy

memory and disk space and this is enough to cause problems all by itself.

They also live at very low levels in the operating system and can

interfere in unexpected ways with other parts of the system. We have

also discovered errors in most viruses which can cause unexplained

crashes and strange behavior.



Disinfectant recognizes all of the currently known Macintosh system

viruses. It also recognizes all the known variations and clones of these

viruses. Furthermore, Disinfectant also recognizes many possible

unknown variations and clones. It will both detect the viruses and, when

possible, repair files which have been infected by the viruses.



Disinfectant will not recognize all possible viruses: only the ones it has

been configured and programmed to recognize. If a new virus or strain

appears, we will have to modify the program to recognize it, and you will

have to get a new copy of the program.



Disinfectant does not recognize application-specific scripting or macro

language viruses. These include the “Dukakis,” “Three Tunes,” and

“MerryXMas” HyperCard viruses and the many cross-platform

Microsoft Word 6 and Excel 5 macro viruses.



The Microsoft macro viruses are currently a major problem, especially

for Word 6 users. If you need protection against these viruses, we

recommend a commercial Macintosh anti-viral program. You do not need

to worry about these viruses if you do not use Word 6 or Excel 5.



Unfortunately, because there are so many Microsoft macro viruses, and

so many new ones keep appearing, we do not have the resources at

Northwestern University to attempt to combat them in Disinfectant.



Disinfectant also includes a virus protection extension (INIT). When

properly installed, the Disinfectant INIT will protect an uninfected system

against infection by any of the known Mac system viruses.



Viruses should not be confused with other types of destructive software

such as “worms” and “Trojan horses.”



A “worm” is a program which replicates and spreads, but does not attach

itself to other programs. Unlike a virus, it does not require a host to

survive and replicate. Worms usually propagate over a network of

computers. They are not spread through the sharing of software or disks.

The most well-known example is the Fall 1988 Internet worm, which

infected and disabled several thousand government and university UNIX

computers in a single day.



A “Trojan horse” is a program which appears to do something useful, yet

additionally does something destructive behind your back. An example

would be game or other program which quietly erased your hard drive in

the background while you used the program. Trojan horses do not

replicate.



Disinfectant does not attempt to address the problems of worms and

Trojan horses.



There is no need to panic over the current virus situation. However, you

should take the problem seriously. Using Disinfectant, it only takes a few

minutes per week to effectively protect your Macintosh against the known

viruses. See the section titled “Recommendations” for a short list of the

simple things we suggest you do to protect your Mac.



There is a misconception that you can protect your Macintosh against

viruses by merely avoiding shareware and freeware software. This is far

from the truth. There have been many reported cases of (inadvertently)

infected commercial software, while most of the major national sources

of freeware and shareware software are remarkably virus-free.



The virus problem is serious, but even more serious is the tendency to

overreact to the threat. Organizations which impose severe restrictions

on the use of personal computers and personal computer software are

doing more harm than good. For example, some companies keep computers

in locked rooms and do not permit their employees to use unapproved

software. Some companies have even gone so far as to prohibit their

employees from joining bulletin boards or user groups! These restrictions

are completely unnecessary and are, in fact, very dangerous. The heart

of the personal computer revolution (especially the Macintosh revolution)

is the empowerment of the individual. At their best, personal computers

are extensions of each individual’s imagination, unfettered by arbitrary

rules and regulations imposed by the corporate MIS priesthood. We cannot

let the virus problem and other security concerns endanger this

revolution.



The analogy between biological viruses and computer viruses is striking.

Both of them replicate and they both require the assistance of a host to

survive. In both cases, the infected system is sometimes severely

damaged. With both kinds of viruses, it is sometimes possible to remove

the infection without damaging the system and it is sometimes possible to

inoculate or vaccinate the system to protect it against future infection.



As with all analogies, however, it is possible to carry the analogy

between biological and computer viruses too far. Computers are not living

organisms. Biological viruses usually occur naturally and are almost

never created by people. Computer viruses are always created by people;

they never occur naturally. Most importantly, it is not possible to

compare the enormous suffering caused by biological viruses such as HIV

to the comparatively meaningless damage caused by computer viruses.



Disinfectant is distributed electronically. When a new virus is discovered,

we usually release a new version of Disinfectant to recognize the virus

within a few days. The official anonymous FTP site is:



   ftp://ftp.nwu.edu/pub/disinfectant/



Disinfectant is not a commercial product. We cannot offer typical

commercial services such as telephone support, mailing lists, or upgrade

services.



Macintosh users who do not have access to electronic sources of free and

shareware software may obtain a copy of Disinfectant by sending a

self-addressed stamped envelope and a floppy disk (800K or 1440K) to

the author at the address given at the end of this manual. People outside

the U.S. may send an international postal reply coupon instead of US

stamps (available from any post office). Please use sturdy envelopes,

preferably cardboard disk mailers.