LESSON 18

POPULAR INFECTION METHODS USED BY COMPUTER VIRUSES [2]

Task 1. Read and translate the text:

Задание 1. Прочитайте и переведите текст:

To say that computer viruses infect your computers is not enough; every computer virus has its own special way of wrenching control from normal files. Viruses can append themselves onto, insert themselves into, or wrap themselves around normal executable program files. Some viruses combine techniques in order to achieve a higher level of adaptability. Viruses can remain resident in memory and can intercept user commands and DOS system calls. They can redirect system I/O through themselves or go for the jugular and simply replace good files with viral impersonators.

Like movies, songs, and television shows, computer programs have a beginning, middle, and an end. Usually, when a computer program is first loaded into memory, an opening title screen is displayed. That's the beginning, or top, of the program. The various functions you call up as you use the program constitute its middle, and when exiting you're at the program's end. What most users don't know is that the binary representations of computer program commands that actually make computer pro­grams run are not necessarily stored on disks in the same order as that in which they will be used.

In computer programming jargon, a program's lines of text are called strings of text, or just plain strings. While the first thing users see when they load and runa particular computer program might be a string of text saying "Welcome to FOOBAR version 9.7," the actual characters of text are usually stored eitherat the very beginning or at the end of the program's on-disk binary code.

Therefore, were you to view a.COM or.EXE file with binary file viewer, you would most likely find a bucketful of text strings stored at the beginning and end of the program file, regardless of where or how they are actually displayed during program usage.

Computer program compilers (other programs that convert lists of computer commands into executable program files) store text displays and other computer commands in whatever manner is most efficient for computers to use. When programs are run, compiled executables tell computers where in memory or where on disk they can find required text strings, commands, functions, and more. Computer virus programmers, knowing intimately how their target files operate, ingeniously exploit computers' handling of binary program file executions.

There are six popular methods employed by most computer viruses to steal control from normal executable files: appending, insertion, interception, redirection, replacement, the viral shell.

While other forms of system corruption surely exist, these are by far the dominant techniques preferred by rogue program authors.

Task 2. Answer the following questions:

Задание 2. Ответьте на следующие вопросы:

1. What does every computer virus have?

2. What are strings of text?

3. What do computer program compilers store?

4. What do computer virus programmers exploit?

5. What are six popular methods used by computer viruses?

Task 3. Find the Russian equivalents for the words and word – combinations given below:

Задание 3. Дайте русские эквиваленты следующим словосочетаниям:

Executable program files, viral impersonators, binary representation of computer program, program’s on-disk binary code, binary file viewer, bucketful of text strings, computer program compiler, binary program file execution.

Task 4. Complete the sentences according to the text:

Задание 4. Дополните предложения:

1. Some viruses combine techniques in order to ….

2. Like movies, computer programs have ….

3. Computer program compilers store ….

4. When programs are run, compiled executables tell computers ….

5. There are six methods used by computer viruses to steal control from normal executable files ….

Task 5. Retell the text:

Задание 5. Перескажите текст, используя новые слова и словосочетания: