Viruses...what are they?

ok here is a tutorial a friend of mine wrote and he gave it to me and i found it very useful in understanding wot a virus i hope the newbies out there who dont know wot it is will find it useful....

Intro To Viruses: An Overview of Computer A.I.
Made by Zcero
[email protected]
ICQ# 58805220
www.binary-chaos.net

Disclaimer: Neither I, or the members of B.C, are responsible for your
actions with the following information. If you are found with this
information it is your own fault. Just remember, information is free,
but it won't is if you are found using it, so if you are looking to blame
someone it won't be us and in the words of a Vulgar kid "**** off"!
Thanks for reading Intro To Viruses: An Overview of computer A.I.

What is a computer Virus?
A Computer Virus is a program that was written in a computer
language such as Pascal, C++, or assembly that can replicate itself. A
virus is said to be one of the closest forms of A.I. available to humans
at this time. A.I.? Yup, its true viruses can replicate, attack and even
be spontaneous. A Virus will not just appear on your computer though,
you must first be infected. To understand the Computer Virus you
must first understand what makes one up

Computer Virus Parts
A typical virus has 2 essential parts and one optional part to it. The
two parts that are essential are a search and infection routine. There
are 3 optional parts as well; they are the trigger routine, the ant
detection routine (stealth), and a payload.
First we will start with the search routine. The search routine scans the
floppy, zip or hard drive for its target. It looks for files like lotus etc...It
may also look for boot sectors (read into to hacking 4). It must also
make sure that it scans files to make sure that it doesn't infect them
twice.

The second essential part known as the infection routine takes over
after the search is finished. It unloads the virus on the target, if your
lucky this might be poorly made and you may be able to detect the
virus quickly.

A trigger routine is used for logic bombs. It basically is a clock that
tells the virus when to attack. The trigger releases the payload, which
tells the virus what to do.
Finally there is the ant detection routine. This prevents antiviral
programs from discovering it. When the antiviral program finds the
virus it displays a message, which is intercepted by the virus and is
altered to say, "I'm fine".

Know that you know the parts, its time you know the viruses. There
are 3 types of virus. File infectors, boot infectors, and the macro
viruses.

File Infectors only infect files like lotus. They only spread when you run
the program and are generally easy to find.
Boot viruses infect the boot sector of a disk. They spread when you
use the disk.

Macro Viruses infect files made by a program such as a png. from
fireworks. They spread only when you load the file.
That was easy right? Alright now that you know the viruses, time to
learn how they infect you.

There are 5 main methods, they are as follows: Direct infection, Fast
infection, Slow Infection, Ram-resident infection and sparse infection.
First we will talk about direct.

Direct infection infects files as you open them. If you don't open the
infected file, the virus never spreads.
Fast Infection attacks any file accessed by the infected program. This
is the fast way to destroy a computer. If you have a virus that is fast
infection, you will know.

Slow infection infects only newly created files. This takes forever for
you to find out because it only spreads when you create files.

Ram Resident infection means that the virus is inside the memory and
every time you use memory it infects the files used. This type is fast
and is a pain in the ass to get rid of.

Sparse infection takes its time infecting files and is completely random
on its attacks.

That sums up the first text on viruses. Part II will have explanations on
types of viruses such as file infectors, micro Virus, companion viruses
and much more. It will also take a look back at some of the more
memorable viruses such as the iloveu virus and the Michelangelo virus.

Soon, people will have to re-do all these texts with sections on .JPG virii.
Cool tut.

well the second part will be passed along once i am done reading it :)

Thanks emrys. I thought JPEG viriii was a joke. . .how you gunna make it execute??? Sorry, I mean, uh huh, do you happen to have any online references to JPG virii, I'd really like to see some stuff on how to embed one to execute through some imaging software?

well it is quite simple all it is u disable the hidding of extention and rename the file for example on a VBS virus, picture.vbs.jpg windows recognizes the last extention there for not recognizing it as a vbs file....so u see that it is a vbs file(evil little buggers) but to u it seems a jpg with the icon and all

good stuff ermys, basic but i think it made some good pointers.

Preep

Yeah but whats the fun in that?

check out the second part of the tutorial i posted it :)...u can see the source of old virri :)...have fun