VIRUSES AND OTHER SOFTWARE INFECTIONS
 
WHAT IS A VIRUS?
 
A VIRUS is a computer program with the ability to reproduce and to infect
or penetrate other computer programs.  A virus can reproduce itself into other
computing systems from the one in which the virus was created.  The virus
"infected" program is generally brought into a computing system from public
bulletin boards and public domain software.  Networks like BITNET can also
serve as a "carrier" for a virus infected program.  However, the program must
be EXECUTED at the new site before it can become active.
 
A WORM is a computer program that squirms and wiggles and "worms" its way
through computer systems changing or altering little pieces of information
as it travels.  A computer worm does not reproduce itself.
 
A TROJAN HORSE is one method of spreading a computer virus.  Similar to the
one in Greek mythology, a Trojan Horse is a computer program that contains
hidden computer instructions.  It does more than what it appears to do.  In
other words, a trojan horse program may be a computer game with lots of bells
and whistles, but it may also carry a virus or look for your password or
examine your names file to use for spreading further.  A favorite trojan
horse program among universities is a student written program that shows a
normal logon screen on the CRT.  An unsuspecting user sits down to the
PC and tries to logon to the network, but a message is shown on the screen
indicating that the network is busy and to please try to access again in 30
minutes.  However, the program has captured the user's logon and password and
saved it in a file for later use.
 
A LOGIC BOMB is segment of a computer program that activates its destructive
program logic based upon a logical happening.
A logic bomb is dormant until triggered by a date and time or by an event.
A time bomb is activates at a given date and time and an event bomb activates
when a given event occurs.  A common event bomb would be to destroy all
payroll data when a given payroll account, presumably the event bomb author's
account, is no longer processed to receive pay (he is no longer with the
company.  A logic bomb can be attached to a virus as was suspected with the
Columbus Day or Friday the 13th Virus that was supposed to hit last October.
 
TRAP DOORS are segments of computer programs designed to allow the author
access to information outside of their normal level of authority.  A trap door
is generally intentionally hidden within a computer program and used only when
needed.  Trap doors are often written as commands or transactions that permit
the user to gain instant, easy access to the information.
 
 
PROTECTING YOUR ACCOUNTS
     The best way to protect your CMS and MVS accounts is to not share them
with others and to change your passwords frequently.  It is a relatively
simple procedure to secure a new account for another if needed and if
certain information is needed to be shared, the UKCC Consultants in 107
McVey Hall can help you with using the AUTOLINK and ACCESS commands to
permit data to be shared without sharing passwords (accounts).
 
     Passwords should be a minimum of four positions in length and should be
changed at least every three months or whenever you feel the secrecy of
your password may have been compromised.  It is important that you select a
password that you can remember so that you don't need to write it down; however
passwords should not be the name of your wife or children or yourself, they
should not be your house number or social security number or birth date, and
they should not be anything else that may be easy for another to guess.  One
technique for selecting a password is to use a common word of 2 or more
syllables, but reversing the syllables such as ADACAN for CANADA and TUCKYKEN
for KENTUCKY and VISIONTELE for TELEVISION.  Another approach would entail
intermingling two different types of information such as ones house number
with ones name.  An example of this would be to use J1A2C8K9 which was deter-
mined by mixing the name JACK with the house number 1289.  A third alternative
would be to write down a common password like WILDCATS but to remember an
offset key like 3.  Then when you enter the password you would offset each
letter by 3 letters to come out with ZLOGFDWV.  The offset key could be any-
thing like converting the letters to numbers, etc.  With this method you
can write your password down and just have to memorize your offset.
     A CMS password can be changed by using the PASSWORD command.
A consultant in 107 McVey Hall can help you if you have any questions
or problems with this.