Introduction to computer viruses!!

[ashtonfarell]

Types of Viruses

1. Polymorphic Virus
2. Stealth Virus
3. Retrovirus
4. Multipartite Virus
5. Armored Virus
6. Companion Virus
7. Phage Virus
8. Macro Virus

Polymorphic Viruses
- Polymorphic viruses change form in order to avoid detection. These
types of viruses attack your system, display a message on your
computer, and delete files on your system. The virus will attempt to
hide from your antivirus software. Frequently the virus will encrypt
parts of itself to avoid detection. When that happens it's called
mutation.

Stealth Virus - This type of virus attempts
to avoid detection by masking itself from applications. It may attach
itself to the boot sector of the hard drive. When a system utility or
program runs, the stealth virus redirects commands around itself in
order to avoid detection. An infected file may report a file size
different from what is actually present in order to avoid detection. It
may also move itself around your computer to different folders during a
virus scan to avoid detection.

Retrovirus - This virus
attacks or bypasses the antivirus software installed on your computer.
You can consider a retrovirus to be a "anti-antivirus". It can directly
attack your antivirus software and potentially destroy the virus
definition database file. This loss of information will leave you with
a false sense of security. This type of virus may also directly attack
the antivirus to create bypasses for the virus.

Multipartite Virus
- This virus attacks your system in multiple ways. It may attempt to
infect your boot sector, infect all you executable files, and destroy
your applications files. The hope her is that you wont be able to
correct all the problems and will allow the infestation to continue. It
attacks your boot sector, infects application files, and attacks your
microsoft word documents.

Armored Virus - This virus
makes itself difficult to detect or analyze. Armored viruses cover
themselves with protective code that stop debuggers or disassemblers
for examining critical elements of the virus. The virus may be written
in such a way that some aspects of the programming act as a decoy to
distract analysis while the actual code hides in other areas in the
program. The more time it takes to de-construct the virus, the longer
it will live. The longer it can live, the more time it has to replicate
and spread to as many machines as possible.

Companion Virus
- This virus attaches itself to legitimate programs and then creates a
program with a different file extension. This file may reside on your
systems temporary directory. When the user types the name of the
legitimate program, the companion virus executes instead of the real
program. This hides the virus from the user (effectively). Many of the
viruses that are used to attack windows systems make changes to program
pointers in the registry so that they point to the infected program.
The infected program will perform it's dirty deed and then start the
real program.

Phage Virus - This virus modifies and
alters other programs and databases. The virus infects all of these
files. The only way to remove this type of virus is to reinstall the
programs that are infected. If you miss even a single incident of this
virus on the victim system, the process will start again and infect the
system once more.

Macro Virus - This virus exploits the
enhancements made to many application programs. Programs such as word
and excel allow programmers to expand the capability of the
application. Word, for example, supports a mini - BASIC programming
language that allows files to be manipulated automatically. These
programs in the document are called macros. For example, a macro can
tell your word processor to spell-check your document when it opens.
Macro viruses can infect all the documents on you system and spread to
other systems using mail or other methods.

[Euphoracle]

Thanks for the copy-and-paste.

[Insectoid]

http://cro-dota.org/forum/printthread.php?tid=154

[qmanjr5]

Still, I think it was helpful.
Thanks for this; I never really did know the TYPES of viruses.

All I ever bothered to learn was how to create them

[USEC_OFFICER]

Nice, now I know, and knowing is half the battle.

[Turing_Gamer]

Mark the descrpition of the viruses as a sticky. It could come in handy.

[USEC_OFFICER]

What is a sticky? They always appear above the other threads, but they don't seem to do anything.

[SNIPERDUDE]

A sticky is the same as any other thread, but is kept at the top of the thread index because they are noted as important. So when you search through the threads, the stickys will always be at the top so it is easy to find/access.