Sara, a user, downloads a keygen to install pirated software. After running the keygen, system performance is extremely slow and numerous antivirus alerts are
displayed. Which of the following BEST describes this type of malware?

A.
Logic bomb

B.
Worm

C.
Trojan

D.
Adware

Explanation:
In computers, a Trojan is a program in which malicious or harmful code is contained inside apparently harmless programming or data in such a way that it can get
control and do its chosen form of damage, such as ruining the file allocation table on your hard disk. In one celebrated case, a Trojan was a program that was
supposed to find and destroy computer viruses. A Trojan horse may be widely redistributed as part of a computer virus.
Incorrect Answers:

A: A logic bomb is a piece of code intentionally inserted into a software system that will set off a malicious function when specified conditions are met. For example,
a programmer may hide a piece of code that starts deleting files should they ever be terminated from the company.
B: A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. Often, it uses a computer network to
spread itself, relying on security failures on the target computer to access it. Unlike a computer virus, it does not need to attach itself to an existing program. Worms
almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted
computer. A computer worm is not what is described in this question. Therefore, this answer is incorrect.
D: Adware is free software that is supported by advertisements. Common adware programs are toolbars that sit on your desktop or work in conjunction with your
Web browser. They include features like advanced searching of the Web or your hard drive and better organization of your bookmarks and shortcuts. Adware can
also be more advanced programs such as games or utilities. They are free to use, but require you to watch advertisements as long as the programs are open.
Since the ads often allow you to click to a Web site, adware typically requires an active Internet connection to run.
Most adware is safe to use, but some can serve as spyware, gathering information about you from your hard drive, the Web sites you visit, or your keystrokes.
Spyware programs can then send the information over the Internet to another computer. So be careful what adware you install on your computer. Make sure it is
from a reputable company and read the privacy agreement that comes with it. Adware is not what is described in this question. Therefore, this answer is incorrect.

http://searchsecurity.techtarget.com/definition/Trojan-horse http://en.wikipedia.org/wiki/Logic_bomb
http://techterms.com/definition/adware
http://en.wikipedia.org/wiki/Computer_worm