1. Computer Virus

3. The First Computer Virus
 Elk Cloner is one of the first known microcomputer
viruses that spread "in the wild," i.e., outside the
computer system or lab in which it was written.
 It was written around 1982 by a 15-year-old high
school student named Rich Skrenta for Apple II
systems.

4. Types of viruses
Boot viruses
Program viruses
Multipartite viruses
Stealth viruses
Polymorphic viruses
Macro Viruses

5.  Infect floppy disk boot records or master boot
records in hard disks.
 They replace the boot record program copying it
elsewhere on the disk or overwriting it.
 Boot viruses load into memory if the computer
tries to read the disk while it is booting.
Examples: Form, Disk Killer, Michelangelo, and Stone virus

6.  infect executable program files, such as those
with extensions like
.BIN, .COM, .EXE, .OVL, .DRV (driver) and
.SYS (device driver).
 These programs are loaded in memory during
execution, taking the virus with them.
 The virus becomes active in memory, making
copies of itself and infecting files on disk.
Examples: Sunday, Cascade

7.  A hybrid of Boot and Program viruses
 They infect program files and when the
infected program is executed, these viruses
infect the boot record.
 When you boot the computer next time the
virus from the boot record loads in memory
and then starts infecting other program files
on disk.
Examples: Invader, Flip, andTequila

8.  These viruses use certain techniques to avoid
detection
 They may either redirect the disk head to
read another sector instead of the one in
which they reside or they may alter the
reading of the infected file’s size shown in the
directory listing.
Examples: Frodo, Joshi,Whale

9.  A virus that can encrypt its code in different
ways so that it appears differently in each
infection.
 These viruses are more difficult to detect.
Examples: Involuntary, Stimulate, Cascade, Phoenix, Evil, Proud, Virus 101Examples: Involuntary, Stimulate, Cascade, Phoenix, Evil, Proud, Virus 101Examples: Involuntary, Stimulate, Cascade, Phoenix, Evil, Proud, Virus 101Examples: Involuntary, Stimulate, Cascade, Phoenix, Evil, Proud, Virus 101Examples: Involuntary, Stimulate, Cascade, Phoenix, Evil, Proud, Virus 101
Examples: Involuntary, Stimulate, Cascade, Phoenix, Evil,
Proud,Virus 101

10.  A macro virus is a new type of computer virus
that infects the macros within a document or
template.
 When you open a word processing or
spreadsheet document, the macro virus is
activated and it infects the Normal template
(Normal.dot)-a general purpose file that
stores default document formatting settings.

11.  Every document you open refers to the
Normal template, and hence gets infected
with the macro virus.
 Since this virus attaches itself to
documents, the infection can spread if such
documents are opened on other computers.
Examples: DMV, Nuclear,Word Concept.

13.  Adware or advertising-supported software
is any software package which automatically
plays, displays, or downloads advertisements
to a computer after the software is installed
on it or while the application is being used.
Some types of adware are also spyware and
can be classified as privacy-invasive software.

14.  Malware, short for malicious software, is
software designed to infiltrate a computer
without the owner's informed consent. The
expression is a general term used by
computer professionals to mean a variety of
forms of hostile, intrusive, or annoying
software or program code. The term
"computer virus" is sometimes used as a
catch-all phrase to include all types of
malware, including true viruses.

15.  Once a malicious program is installed on a system, it is
essential that it stay concealed, to avoid detection and
disinfection.The same is true when a human attacker
breaks into a computer directly.Techniques known as
rootkits allow this concealment, by modifying the host
operating system so that the malware is hidden from the
user. Rootkits can prevent a malicious process from being
visible in the system's list of processes, or keep its files
from being read. Originally, a rootkit was a set of tools
installed by a human attacker on a Unix system where the
attacker had gained administrator (root) access.
Today, the term is used more generally for concealment
routines in a malicious program.

16.  A backdoor is a method of bypassing normal
authentication procedures.Once a system has
been compromised one or more backdoors may
be installed in order to allow easier access in the
future. Backdoors may also be installed prior to
malicious software, to allow attackers entry
 Crackers typically use backdoors to secure
remote access to a computer, while attempting
to remain hidden from casual inspection.

17.  Spam is the abuse of electronic messaging systems
(including most broadcast media, digital delivery
systems) to send unsolicited bulk messages
indiscriminately. While the most widely recognized
form of spam is e-mail spam
 E-mail spam, known as unsolicited bulk Email (UBE),
junk mail, or unsolicited commercial email (UCE), is
the practice of sending unwanted e-mail messages,
frequently with commercial content, in large
quantities to an indiscriminate set of recipients.

18.  Spyware is a type of malware that is installed on
computers and that collects information about
users without their knowledge. The presence of
spyware is typically hidden from the user.
Typically, spyware is secretly installed on the
user's personal computer.
Sometimes, however, spywares such as
keyloggers are installed by the owner of a
shared, corporate, or public computer on purpose
in order to secretly monitor other users.

19.  Wikipedia

20. Thank
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