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					                COMPUTER VIRUSES

                                        (anonymous)

<1>WHAT IS A COMPUTER VIRUS:

       The term usually used to define a computer virus is:
       ' A computer virus is often malicious software which
          replicates itself'
                    [ Podell 1987 for similar definition ]

       - COMPUTER VIRUSES ARE BASICALLY PROGRAMS, LIKE A
         SPREADSHEET OR A WORD PROCESSOR.
       - PROGRAMS WHICH CAN INSERT EXECUTABLE COPIES OF ITSELF INTO
         OTHER PROGRAMS.
       - PROGRAMS THAT MANIPULATES PROGRAMS, MODIFIES OTHER
         PROGRAMS AND REPRODUCE ITSELF IN THE PROCESS.



      Comparing Biological viruses & Computer viruses

*************************************************************
* Attack specific                * Attack specific                *
*            body cells          *      programs (*.COM *.EXE)    *
*************************************************************
* Modify the genetic information * Manipulate the program:        *
* of a cell other than previous 1*          It performs tasks     *
*************************************************************
*   New viruses grow in the      * The infected program    produces *
*          infected cell itself *           virus programs        *
*************************************************************
* Infected cells aren't infected * Program are infected only once*
* more than once by the same cell*               by most programs*
*************************************************************
* An infected organism may not   * The infected program can work *
* exhibit symptoms for a while   * without error for a long time *
*************************************************************
* Not all cells with which the   * Program can be made immune     *
* virus contact are infected     * against certain viruses        *
*************************************************************
* Viruses can mutate and thus    * Virus program can modify       *
* cannot be clearly told apart   * themselves & possibly escape *
*                                * detection this way             *
*************************************************************



       However, " computer virus " is just another name for a class
       of programs. They can do anything that another program can.
       The only distinguishing characteristic is the program has
       ability to reproduce and infect other programs.



<2>WHAT KIND OF PROGRAM ARE CHARACTERIZED AS A VIRUS PROGRAM:

       - PROGRAM WHICH HAS CAPABILITY TO EXECUTE THE MODIFICATION
         ON A NUMBER OF PROGRAMS.
       - CAPABILITY TO RECOGNIZE A MODIFICATION PERFORMED ON A
         PROGRAM.(THE ABILITY TO PREVENT FURTHER MODIFICATION OF
                         THE SAME PROGRAM UPON SUCH RECONDITION.)
       - MODIFIED SOFTWARE ASSUME ATTRIBUTES 1 TO 4.

 <3>HOW DOES A VIRUS SPREAD:
       A computer virus can only be put into your system either by
       yourself or someone else. One way in which a virus can be
       put into your computer is via a Trojan Horse.

       -TROJAN HORSE IS USUALLY CONTAMINATED IN DISKS WHICH ARE
        PARTICULARY PIRATED COPIES OF SOFTWARE. IT IS SIMPLY A
        DAMAGING PROGRAM DISGUISED AS AN INNOCENT ONE. MANY
        VIRUSES MAYBE HIDDEN IN IT, BUT T.H. THEMSELVES DO NOT
        HAVE THE ABILITY TO REPLICATE.

        Viruses also can be spread through a Wide Area network
        (WAN) or a Local Area Network (LAN) by telephone line.
        For example down loading a file from a local BBS.

       BBS(bulletin board system)-AN Electronic mailbox that user
       can access to send or receive massages.

       However, there seems to be countless numbers of ways to
       become infected. Every-time you down loads a program from
       somewhere or borrowed a disk from a friend, you are taking
       a risk of getting infected.




<4>DAMAGES AND SIGNS OF INFECTION:

      a.> Fill Up your P.C. with Garbage:
      As a virus reproduces, it takes up space. This space cannot
      be used by the operator. As more copies of the virus are
      made, the memory space is lessened.

      b.> Mess Up Files:
      Computer files have a fixed method of being stored. With
      this being the case, it is very easy for a computer virus to
      affect the system so some parts of the accessed files cannot
      be located.

      c.> Mess Up FAT:
      FAT(the File Allocation Table) is the method used to contain
      the information required about the location of files stored
      on a disk. Any allocation to this information can cause
      endless trouble.

      d.> Mess   Up The Boot Sector:
      The boot   sector is the special information found on a disk.
      Changing   the boot sector could result in the inability of the
      computer   to run.

      e.> Format a Disk/ Diskette:
      A virus can simply format a disk as the operator would with
      the format or initialise command.

      f.> Reset The Computer:
      To reset the computer, the operator or the user only has to
      press a few keys. The virus can do this by sending the codes
      to the operating system.

      g.> Slowing Things Down:
      As the name implies, the object of the virus is to slow down
      the running line of the program.

      h.> Redefine Keys:
      The computer has been program to recognize that certain
      codes/ signals symbolize a certain keystroke. The virus
      could change the definition of these keystrokes.

      i.> Lock The Keyboard: redefining all keys into an empty key.


<5>WHAT TO DO AFTER VIRUS ATTACKS:
       When signs of a virus attack have been recognized,
       the virus has already reproduced itself several times.
       Thus, to get rid of the virus, the user has to hack down
       and destroy each one of these copies. The easier way is to:

       1. Have the original write protected back-up copy of your
          operating system on a diskette.
       2. Power down the machine.
       3. Boot up the system from the original system diskette.
       4. Format the hard disk.
       5. Restore all back-ups and all executable program.

 *If it's not effective, power down and seek for professional help*


<6> TYPE OF VIRUSES:
    a.> OVER-WRITING VIRUSES

    b.> NON-OVERWRITNG VIRUSES

    c.> MEMORY RESENDENT VIRUSES

<7>PRACTICE SAFE HEX:
       Viruses are a day to day reality. Different activities
       leads to different exposure. To protect oneself from a
       virus, several things can be done:
       1. Avoid them in the first place.
       2. Discovering and getting rid of them.
       3. Repairing the damage.
       The simple thing that can cut down on exposure rate are to:
       avoid pirate software, checking programs that have been down
       loaded form the BBS before running them. Make sure that you
       have sufficient backups.




<8> ANTIVIRUS PRODUCTS COMPANY:
       The pace at which new antiviral products have been pouring
   onto the market has accelerated rapidly since the major
   infection of 1988. Indeed, by early 1989, there were over 60
   proprietary products making varied claims for effectiveness in
   preventing or detecting virus attacks.

   For:   IBM PCs   &   Compatibles

     DISK DEFENDER              PC SAFE            McAFEE SCAN
DIRECTOR TECHNOLOGIES    THE VOICE CONNECTION   McAFEE ASSOCIATES
906 University Place     17835 Skypark Circle   4423 Cheeney Street
Evanston, IL 60201       Irvine, CA 92714       Santa Clara, CA 95054
TEL: (408) 727-4559      TEL: (714) 261-2366    TEL: (408) 988-3832
Price: $ 240.00 U.S.     Price: $ 45.00 U.S.    Price: $ 80.00 U.S.
Class : HARD.2           Class : SOFT.1         Class: SOFT.3


   For: Macintosh Plus, SE, & II(Apple)

                               VIREX
                            HJC SOFTWARE
                          P.O. BOX 51816
                          Durham, NC 27717
                          TEL: (919) 490-1277
                          Price: $ 99.95 U.S.
                          Class : SOFT.3


*Class 1(infection prevention class)*
       Most Class 1 products are unable to distinguish between an
    acceptable or unacceptable access to an executable program.
    For example, a simply DOS COPY command might cause the waring
    appear on screen.
*Class 2(infection detection class)*
       All Class 2 products are able to distinguish all DOS
    commands. Addition to Class 1's prevention fuction, it is able
    to protect all COM and EXE files from infection.
*Class 3(Top class)*
       Class 3 products are cable of both prevention & detection
fuctions.    And they are cable of removing the infection viruses.


            <1>. COMPUTER VIRUSES a high-tech disease
                 WRITTEN BY: RALF BURGER
                 PUBLISH BY: ABACUS, U.S.A

            <2>. DATA THEFT
                 WRITTEN BY: HUGO CORNWALL
                 PUBLISH BY: PONTING-GREEN, LONDON

            <3>. COMPUTER VIRUSES,WORMS,DATA DIDDLERS,KILLER
                 -PROGRAMS, AND OTHER THREATS TO YOUR SYSTEM
                 WRITTEN BY: JOHN McAFEE & COLIN HAYNES
                 PUBLISH BY: ST.MARTIN'S PRESS, U.S.A

               *************************************************
               * COMPUTER VIRUSES CRISIS     * THE SECRET WORLD *
               * WRITTEN BY: PHILP E FITES   *    OF COMPUTER    *
               ****************************** WRITTEN BY:        *
               * COMPUTE'S COMPUTER VIRUSES * ALLAN LNNDELL      *
               * WRITTEN BY: RALPH ROBERTS   *                   *