Adware
is any software application in which advertising banners are shown while a
program is running. The ads are delivered through pop-up windows or bars that appear on the program’s user interface.

Spyware
is software that is installed on a computing device without the end user’s awareness.
Such software is debated because even though it is sometimes installed for
relatively harmless reasons, it can violate the end user’s privacy and has the
potential to be abused.

Scareware is a form of malware which tricks users into buying unwanted
software
and it tricks users into believing their computer is infected with a virus,
then says that they download and pay for fake
antivirus software to remove it.

Ransomware is a type of malicious software that threatens to
publish the victim’s data or continuously block access to it unless a money is paid. More advanced malware uses a technique
in which it encrypts the victim’s files,
making them inaccessible, and demands a money payment to decrypt them.

Rootkit is an application
that hides its existence or existence of another application on the computer,
using some of the lower layers of the operating system, which makes them almost
undetectable by common anti-malware software.

Phishing
is a cybercrime in which a target or targets are contacted by email,
telephone or text message by someone posing as a legitimate institution to lure
individuals into providing sensitive data such as personally identifiable
information, banking and credit card details, and passwords.

A brute force attack is a
trial-and-error method used to obtain information such as a user password or
personal identification number (PIN). In a brute force attack, automated software is used to generate a large
number of consecutive guesses as to the value of the desired data.

A
denial-of-service attack is a security event that occurs when an attacker takes
action that prevents legitimate users from accessing targeted computer systems,
devices or other network resources.

Packet-sniffing software examines data
packets and checks them against predetermined parameters. A network switch can
be configured to send all data that passes through it to a particular IP
address where it can be examined.

Packet sniffing is often used legitimately by
organisations in order to analyse network trends such as which addresses
receive how much traffic. It is also sometimes used in order to detect
intrusion attempts. Wireless LANs can use special Wi-Fi adapters to sniff data
from specific channels.

Wireless communications are vulnerable to
data interception by malicious individuals who can sniff the packets of data
quite easily as they are not constrained by physical cables. Intruders can
access wireless signals from over 300 metres away so they can easily escape
detection.

The best way to defeat data
interception is to use some form of strong encryption. Wireless transmissions should make use of the WPA
protocol at least, where the transmissions are encrypted using keys of at least
128 bits, often added to each packet and generated again for each packet. At
least if such strong encryption is used, any intercepted data should be unreadable.