1D0-470
Michel wants to write a computer virus that will cripple UNIX systems. What is going to be the main obstacle preventing him from success?

A.
UNIX computers are extremely difficult to access illicitly over the internet, and therefore computer viruses are not an issue with UNIX systems

B.
Due to the file permission structure and the number of variations in the UNIX hardware architectures, a virus would have to gain root privileges as well as identify the hardware and UNIX flavor in use.

C.
Due to availability of effective free anti-virus tools, computer viruses are caught early and often. Michel’s virus would have to evade detection for it to succeed.

D.
Due to the extensive use of ANSI “C” in the programming of UNIX, the virus would have to mimic some of the source code used in the infected iteration of the UNIX operating system

Explanation:
Unix has a strong permission structure that in order to breach the system, root privilege will be required. Root is a superuser account, and is kept locked up by a secure system because of the power that the root user has. Hardware variations will make the use of machine and assembly language difficult. Most viruses depend on modifying machine instructions, and the instruction set can vary widely. Since Unix is written in C language, the operating system is very portable. But to write an effective virus, the use of machine language is NOT portable, so the virus will not really work on all platforms.
Incorrect Answers:
A: Unix systems are easy to access, and many accounts get cracked due to easy passwords or no passwords at all. However, from the accounts that do get accessed, not much damage can be done. The root account has to be breached in order to do some serious damage.
C: Because of the ingenious variations of virus coding, there still is not an effective detection tool to find new virus attacking the system. Usually a virus is found after the fact, and detection tools are put into place to scan for the virus signature of the new virus. Until the virus is detected, and a detection signature is built and distributed, an effective virus can do a lot of damage.
D: Most Unix source code is freely distributed, so finding out the coding will not be difficult. Since the virus does not operate at the C compiler level, but at a lower machine language level, the virus needs to mimic the machine language generated by that source code, which varies based on platform.