Section C: MALICIOUS and DESTRUCTIVE Programs Virus a program (usually destructive) that attaches to a legitimate program to penetrate the operating system and destroy application programs, data files and the operating system itself. An insidious aspect of a virus is its ability to spread throughout the host system and on the other systems before penetrating its destructive acts. It grows geometrically, which makes tracing its origin extremely difficult. Virus usually attach themselves to the following type of files: 1) an EXE program file, 2) an OVL (overlay) program file, 3) the boot sector of a disk and 4) a device driver program. Mechanism for spreading viruses includes e-mail attachments, downloading of public domain programs from the internet, and using illegal bootleg software. Worm A software program that virtually burrows into the computer’s memory and replicates itself into areas of idle memory. Systematically occupies idle memory until the memory is exhausted and the system fails. It differs from viruses in that the replicated worm modules remain in contact with the original worm that controls their growth, whereas the replicated virus modules grow independently. Logic bomb A destructive program, such as a virus, that some predetermined event triggers. Often a date (such as Friday the 13 th , April fool’s Day, or the 4 th of July) will be the logic bomb’s trigger. Events of less public dominance, such a dismissal of an employee, have also triggered these bombs. Back Door Also called a trap door. A software program that allows unauthorized access to a system without going through the normal (front door) log-on procedure. The purpose of the back door may be to provide easy access to perform program maintenance, or it may be to penetrate a fraud or insert a virus into the system.
Section C: MALICIOUS and DESTRUCTIVE ProgramsVirus a program
(usually destructive) that attaches to a legitimate program to
penetrate the operating system and destroy application programs,
data files and the operating system itself. An insidious aspect of
a virus is its ability to spread throughout the host system and on
the other systems before penetrating its destructive acts. It grows
geometrically, which makes tracing its origin extremely difficult.
Virus usually attach themselves to the following type of files: 1)
an EXE program file, 2) an OVL (overlay) program file, 3) the boot
sector of a disk and 4) a device driver program. Mechanism for
spreading viruses includes e-mail attachments, downloading of
public domain programs from the internet, and using illegal bootleg
software.Worm A software program that virtually burrows into the
computers memory and replicates itself into areas of idle memory.
Systematically occupies idle memory until the memory is exhausted
and the system fails. It differs from viruses in that the
replicated worm modules remain in contact with the original worm
that controls their growth, whereas the replicated virus modules
grow independently.Logic bomb A destructive program, such as a
virus, that some predetermined event triggers. Often a date (such
as Friday the 13th, April fools Day, or the 4th of July) will be
the logic bombs trigger. Events of less public dominance, such a
dismissal of an employee, have also triggered these bombs.Back Door
Also called a trap door. A software program that allows
unauthorized access to a system without going through the normal
(front door) log-on procedure. The purpose of the back door may be
to provide easy access to perform program maintenance, or it may be
to penetrate a fraud or insert a virus into the system.Trojan horse
A program whose purpose is to capture IDs and password from
unsuspecting users. These are programs are designed to mimic the
normal log-on procedures of the operating system. When the user
enters his or her ID password, the Trojan horse stores a copy of
them in a secret file. At some later date, the author of the Trojan
horse uses these IDs and passwords to access the system and
masquerade as an authorized user.
