Hacker Jargon

Here are some terms which a computer user must know:
Malware  –  The generic term used  for all forms of software
designed with malicious intent. Viruses, worms, spyware etc.
are all forms of malware. The term  virus  is often used when
malware should really be used as it describes all forms of
malicious software.
Virus  – A computer virus acts  very much like a human virus.
Human viruses are spread, via thumb drives, floppy discs,
network connections etc., to  other PCs.  Viruses need a host
(like a free screensaver program) to spread. By pure definition:
a virus has the ability to spread itself,  via a host, to other
computers.
Worm  –  A worm is much like a virus. The key difference is
worms can spread between PCs without a host (free
screensaver program, downloaded game etc.) These programs rely on computer networks and usually damage files and slow
down networks in their path.
Trojan(horse)  -  A Trojan horse is a seemingly
harmless program that looks to provide value. However, just as
in Greek mythology, a Trojan horse has a secret agenda and
acts as a backdoor to your computer. This backdoor can be
accessed by a hacker to compromise your PC. Trojan horses are
not self-replicating and spread due to users installing them
manually on their PC.
Spyware  –  Spyware tracks a user’s activity by monitoring
browsing habits and keyboard activity and can even take
screenshots while you use your PC. This information is sent
back to the creator  or beneficiary of the spyware. Signs of
spyware include: modified browser homepages, slow internet,
and suspicious looking sites in place of legitimate sites.
Adware  –  Like spyware, adware is software that  may track
visited websites and act as a key logger. Adware tracks this
information to  automatically display  downloaded or installed
adverts to a user. You may wonder why you are being offered
“PC Super Anti Spyware 2011” when using your PC; this is
adware at work. AIM, FlashGet, Deamon Tools, and RealPlayer
are all examples of adware. 
Backdoor - A backdoor is a point of access to a computer that
does not require authentication. An unlocked house back door
gives access to an otherwise secure  home;  a computer
backdoor allows access to your PC without your knowledge or
permission.
Key logger – Key loggers are used to monitor keyboard activity
on a PC. These can be software-based (bundled with Trojan
horses, adware, and spyware) or hardware-based (between the
keyboard cable and the  PC, acoustic etc.) Usually this
information is retrieved across a local network, the internet, or
from the physical device connected to the keyboard.