Boot Sector Virus

 
Boot sector virus is spread is a common one. This virus in 
reproduce itself, will have to move or replace the original boot sector 
podići program with the virus. So when the virus occurs podići akan loaded 
to memory and then the virus will have the ability to control 
standard hardware (eg monitor, printer etc.) and also from the memory of this virus akan 
spread to all who have the drive and connected to the computer (for example: 
Floopy, drive other than drive c:). 
Examples of viruses: 
- Variant virus wyx 
ex: wyx.C (B) menginfeksi boot record and Floopy; 
Length: 520 bytes; 
Characteristics: Memory resident and encrypted. 
- Variant V-sign: 
attack: Master Boot Record; 
Length of 520 bytes; 
Characteristics: live in the memory (memory resident), encrypted, and polymorphic) 
- Stoned.june 4th / bloody!: 
infect: Master Boot Record and Floopy; 
Length of 520 bytes;

Macro virus

 
This type of virus is certainly very often we hear. This virus was written with 
programming language of an application is not the programming language of an Operating System. This virus can be run when the application can creating it self 
running well. For example, if the computer is run mac application 
Word, the macro virus that is made from the Word macro language can be worked on 
system Mac computer is operating. 
Examples of viruses: 
- Variant W97M, eg W97M.Panther 
Length of 1234 bytes, will infect NORMAL.DOT and infect document 
when opened. 
- WM.Twno.A; TW 
The length of 41,984 bytes, will infect document using Ms.Word 
macro language, usually extention: . . DOC and DOT

Life cycle VIRUS

Life cycle of viruses in general, through the 4 stages: 
Dormant phase (Phase Rest / Sleep) 
At this phase the virus is not active. Virus will be activated by a condition 
particular, such as: the date specified, the presence of other programs / be executed 
other programs, etc.. Not all of the virus through this phase. 
Propagation phase (phase distribution) 
At this phase the virus will copy it self to a program or to a 
place of storage media (both hard drives, RAM etc.). Each program is infected 
will be the result of "cloning" the virus (depending on how the virus 
menginfeksinya). 
Trigerring phase (active phase) 
In this phase the virus is active and this is also the trigger conditions by some 
as in the Dormant Phase. 
Execution phase (execution phase) 
At this phase the virus is active before akan perform its function. Like 
delete files, display messages, etc.

Hide ability of self

Hide this capability must be owned by a virus that 
all work well from the beginning until the successful transmission can be realized. 
The steps that are usually made: 
- Program the virus stored in the form of machine code and combined with the program 

others that are considered useful by the user 

- Program Boot virus placed on the record or track on the disk that is rarely 

observed by the computer itself 
- Program viruses sependek may be made, and the resulting file is not too diinfeksi 
change in size 
- The virus does not change the description / information within a file 
- Etc.

The ability to manipulate

Routine (routine) owned a virus will be run after the virus 
infect a file. The contents of a routine this can vary from that is not 
dangerous to do the demolition. This routine is generally used for 
manipulate files or popularize the author! This routine utilizes 
ability of an operating system (Operating System), that have 
the same ability with the operating system. For example: 
a. Create an image or message on the monitor 
b. Change / change-change the label of each file, directory, or the label of the drive in your PC 
c. Manipulate files that be infected 
d. Damage to the file 
e. Disrupt work printer, etc.

The ability to reproduce themselves

The core of the virus is the ability reproduce infect themselves with the file 
another. A virus has been found when the potential victims he akan 
check with them. If not then infected with the virus akan 
aksinya start with the writing of a byte in the file, 
and so copy/ write virus code objects above the target file. Some 
general way by the virus to infect / reproduce themselves is: 
a. File a ditulari akan deleted or renamed. Then created 
a file containing the virus program itself using the file name of the original. 
b. Virus program that is executed / loaded to memory akan directly infect 
files with other ways infected all the files you have.

  
  

The ability to check a program

A virus must also be able to check a file that will ditulari, for example, 
he served infect program extention: . doc, he has to check whether 
document file has been infected or not, because if it is, akan 
useless invected again. This is very useful to improve the ability of a 
virus in the case of speed invected a file / program. The public be 
by viruses is to have / give alert in the file / program that has been infected so easy to recognize by the virus. Sample designation is for example, provides a unique bytes in each file that was infected.

Ability to obtain information

In general, a virus requires a list of names of the files that have 
in a directory. For what? So that he can get a list of files that can be 
he tulari. For example, a macro virus akan menginfeksi all data files MS Word, 
akan find a list of files berekstensi *. doc. Is the ability to gather 
information is required so that the virus can make a list / data files, and 
memilahnya with the search for files that can be ditulari. Usually this data are now 
file a contagious / virus infected files or virus program itself was opened by the user. 
The virus will soon make the collection of data and put it (usually) in the 
RAM, so that when the computer is turned off all the data lost. But this data 
akan created again each time the virus is activated. Typically data is stored 
also as a hidden file by the virus.

CRITERIA VIRUS

A program can be referred to as a virus when meet a minimum of 5 
following criteria: 
1. Ability to obtain information 
2. The ability to check a file 
3. The ability to reproduce themselves and transmit themselves 
4. The ability to manipulate 
5. The ability to hide themselves. 
Now it will try to explain what is short of tiaptiap 
ability, and why this is necessary.

The VIRUS

"A program that can infect other programs by modifying them to include a slighty 
altered copy of itself. A virus can spread throughout a computer system or network 
using the authorization of every user using it to infect their programs. Every programs 
that gets infected can also act as a viral infection that grows " 
(Fred Cohen) 
The first time the term "virus" is used by Fred Cohen in 1984 in 
United States. Computer virus called "virus" because it has some 
fundamental similarities with the virus in the medical term (biological viruses). 
Computer viruses can be defined as a normal computer program. But 
have a fundamental difference with other programs, the virus 
made to infect other programs, change, manipulate 
even merusaknya. There is a need to note here, the virus will only infect 
triggered when the program or programs that have been infected earlier executed, disinilah 
differences with the "worm". This study will not be because the worm will 
divert us from the discussion on this virus.

The Legend of Virus

1949, John von Neumann, said"self altering automata theory" 
which is the result of the research mathematician. 1960, Bell Lab (AT & T), the 
experts in the lab Bell (AT & T)-try to try the theory expressed by John von 
Neumann, with a type of game / game. They create a program 
that can reproduce themselves and the program can be made in the opponent. 
The program is capable of enduring and destroy all other programs, akan 
considered to be the winner. This game eventually became the favorite game in the 
each computer lab. However, the longer the program that created the 
dangerous, so they do control and strict security 
of this game. 1980, these programs are finally known 
with a "virus" is spread out successful laboratory environment, and 
began circulating in the general public.