Computer Viruses

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.


       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: r
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