대부분은 위키피디아에서 참고했지만, 아무래도 한 곳에 모아두는 게 나을 것 같아서 이렇게 올리네요.
파워포인트 파일을 만들 땐, 이 자료들을 그대로 베끼면 안됩니다. 호주와 같은 서양학교들은 에세이나 이런 발표자료 등을 만들 때 만든 사람이 내용을 완벽히 이해했다는 것을 알고 싶어합니다. 때문에, 어떠한 관련된 글을 처음부터 끝까지 읽고 완벽히 이해한 후, 자기자신의 단어를 사용하여 글을 써내려 가야 합니다. 물론, 프레젠테이션의 경우 슬라이드에 문장이 들어가지 않기 때문에 중요한 키워드만 뽑아내어 사용합니다.
Origin of Virus (바이러스의 기원
Unlike a cell, a virus has no way to reproduce by itself. Instead, a biological virus must inject its DNA into a cell. The viral DNA then uses the cell's existing machinery to reproduce itself. In some cases, the cell fills with new viral particles until it bursts, releasing the virus. In other cases, the new virus particles bud off the cell one at a time, and the cell remains alive.
A computer virus shares some of these traits. A computer virus must piggyback on top of some other program or document in order to launch. Once it is running, it can infect other programs or documents. Obviously, the analogy between computer and biological viruses stretches things a bit, but there are enough similarities that the name sticks.
People write computer viruses. A person has to write the code, test it to make sure it spreads properly and then release it. A person also designs the virus's attack phase, whether it's a silly message or the destruction of a hard disk. Why do they do it?
There are at least three reasons. The first is the same psychology that drives vandals and arsonists. Why would someone want to break a window on someone's car, paint signs on buildings or burn down a beautiful forest? For some people, that seems to be a thrill. If that sort of person knows computer programming, then he or she may funnel energy into the creation of destructive viruses.
The second reason has to do with the thrill of watching things blow up. Some people have a fascination with things like explosions and car wrecks. When you were growing up, there might have been a kid in your neighborhood who learned how to make gunpowder. And that kid probably built bigger and bigger bombs until he either got bored or did some serious damage to himself. Creating a virus is a little like that -- it creates a bomb inside a computer, and the more computers that get infected the more "fun" the explosion.
The third reason involves bragging rights, or the thrill of doing it. Sort of like Mount Everest -- the mountain is there, so someone is compelled to climb it. If you are a certain type of programmer who sees a security hole that could be exploited, you might simply be compelled to exploit the hole yourself before someone else beats you to it.
Of course, most virus creators seem to miss the point that they cause real damage to real people with their creations. Destroying everything on a person's hard disk is real damage. Forcing a large company to waste thousands of hours cleaning up after a virus is real damage. Even a silly message is real damage because someone has to waste time getting rid of it. For this reason, the legal system is getting much harsher in punishing the people who create viruses.
History of Virus (바이러스의 역사
The second factor was the use of computer bulletin boards. People could dial up a bulletin board with a modem and download programs of all types. Games were extremely popular, and so were simple word processors, spreadsheets and other productivity software. Bulletin boards led to the precursor of the virus known as the Trojan horse. A Trojan horse is a program with a cool-sounding name and description. So you download it. When you run the program, however, it does something uncool like erasing your disk. You think you are getting a neat game, but it wipes out your system. Trojan horses only hit a small number of people because they are quickly discovered, the infected programs are removed and word of the danger spreads among users.
The third factor that led to the creation of viruses was the floppy disk. In the 1980s, programs were small, and you could fit the entire operating system, a few programs and some documents onto a floppy disk or two. Many computers did not have hard disks, so when you turned on your machine it would load the operating system and everything else from the floppy disk. Virus authors took advantage of this to create the first self-replicating programs.
Early viruses were pieces of code attached to a common program like a popular game or a popular word processor. A person might download an infected game from a bulletin board and run it. A virus like this is a small piece of code embedded in a larger, legitimate program. When the user runs the legitimate program, the virus loads itself into memory and looks around to see if it can find any other programs on the disk. If it can find one, it modifies the program to add the virus's code into the program. Then the virus launches the "real program." The user really has no way to know that the virus ever ran. Unfortunately, the virus has now reproduced itself, so two programs are infected. The next time the user launches either of those programs, they infect other programs, and the cycle continues.
If one of the infected programs is given to another person on a floppy disk, or if it is uploaded to a bulletin board, then other programs get infected. This is how the virus spreads.
The spreading part is the infection phase of the virus. Viruses wouldn't be so violently despised if all they did was replicate themselves. Most viruses also have a destructive attack phase where they do damage. Some sort of trigger will activate the attack phase, and the virus will then do something -- anything from printing a silly message on the screen to erasing all of your data. The trigger might be a specific date, the number of times the virus has been replicated or something similar.
In the next section, we will look at how viruses have evolved over the years.
Floppy disks were factors in the spread of computer viruses.
Evolution (바이러스의 진화
In general, neither executable nor boot sector viruses are very threatening any longer. The first reason for the decline has been the huge size of today's programs. Nearly every program you buy today comes on a compact disc. Compact discs (CDs) cannot be modified, and that makes viral infection of a CD unlikely, unless the manufacturer permits a virus to be burned onto the CD during production. The programs are so big that the only easy way to move them around is to buy the CD. People certainly can't carry applications around on floppy disks like they did in the 1980s, when floppies full of programs were traded like baseball cards. Boot sector viruses have also declined because operating systems now protect the boot sector.
Infection from boot sector viruses and executable viruses is still possible. Even so, it is a lot harder, and these viruses don't spread nearly as quickly as they once did. Call it "shrinking habitat," if you want to use a biological analogy. The environment of floppy disks, small programs and weak operating systems made these viruses possible in the 1980s, but that environmental niche has been largely eliminated by huge executables, unchangeable CDs and better operating system safeguards.
Example (바이러스 예시
Jerusalem Virus (예루살렘 바이러스)
Jerusalem is a DOS file virus first detected in Jerusalem, Israel, in October 1987.
Upon infection, the Jerusalem virus becomes memory resident (using 2kb of memory), and then infects every executable file run, except for COMMAND.COM. .COM files grow by 1,813 bytes when infected by Jerusalem and are not re-infected. .EXE files grow by 1,808 to 1,823 bytes each time they are infected. The virus re-infects .EXE files each time the files are loaded until they are too large to load into memory. Some .EXE files are infected but do not grow because several overlays follow the genuine .EXE file in the same file. Sometimes .EXE files are incorrectly infected, causing the program to fail to run as soon as it is executed.
The virus code itself hooks into interrupt processing and other low level DOS services. For example, code in the virus suppresses the printing of console messages if, for example, the virus is not able to infect a file on a read-only device such as a floppy disk. One of the clues that a computer is infected is the mis-capitalization of the well-known message "Bad command or file name" as "Bad Command or file name".
The program contains one destructive payload that is set to go off on Friday the 13th, all years but 1987. On that date, the virus deletes every program file that was executed. Jerusalem is also known as BlackBox because of a black box it displays during the payload sequence. If the system is in text mode, Jerusalem creates a small black rectangle from row 5, column 5 to row 16, column 16. The rectangle is scrolled up by two lines.
As a result of the virus hooking into the low-level timer interrupt, PC-XT systems slow down to one fifth of their normal speeds 30 minutes after the virus has installed itself. The slowdown is less noticeable on faster machines. The virus contains code that enters a processing loop each time the processor's timer tick is activated.
Symptoms also include spontaneous disconnection of workstations from networks and creation of large printer spooling files. Disconnections occur since Jerusalem uses the 'interrupt 21h' low-level DOS functions that Novell Netware and other networking implementations required to hook into the file system.
Jerusalem was initially very common (for a virus of the day) and spawned a large number of variants. However, since the advent of Windows, these DOS interrupts are no longer used, so Jerusalem and its variants have become obsolete.
Jerusalem is a DOS file virus first detected in Jerusalem, Israel, in October 1987.
Once the Jerusalem virus activated, It stays in memory area.
and then infects every executable file run.
When the computer is infected by Jerusalem virus, the size of executable files grow up.
오래되서 분류가 정확한지는 모르겠습니다만, 발표준비할때 많은 도움이 되었던 자료들입니다. 이걸로 거의 모든 슬라이드를 커버하며 대사를 만들었었기 때문에 간단한 고등학교수준의 발표라면 이 정도면 충분할 것으로 생각합니다.
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