\chapter{Cyber security}

Cyber security is the study of the relation between computers,
networks, and malicious threats and attacks that they are vulnerable
to.

\section{Threats}

\begin{itemize}
    \item \textit{Social engineering} involves exploiting people
        directly for access or information. \textit{Blagging} involves
        obtaining information through deception or impersonation, such
        as calling someone whilst posing as a friend.
        \textit{Phishing} is posing as a legitimate organisation to
        obtain personal information, generally through email.
        \textit{Pharming} involves a bogus website that imitates a
        legitimate one. \textit{Shouldering} involves watching
        somebody enter their personal information.
    \item \textit{Malicious code} is code written to do bad. A
        \textit{virus} does damage on a computer and spreads itself on
        a user's device over the internet. \textit{Spyware} is
        software that monitors, logs, and sends information to the
        spy. For example, a keylogger may record every key a user
        presses and send it to the spy so that information such as a
        password can be extracted. \textit{Adware} is a program that
        is designed to show the user advertisement and a
        \textit{Trojan} is any malware that poses as a legitimate
        software.
    \item \textit{Weak passwords} or \textit{misconfigured access
        rights} may allow an attacker easy access to unauthorised
        data. Access rights would normally restrict certain
        information from certain users.
    \item \textit{Removable media} such as a DVD or USB flash drive is
        a vector by which malware can easily spread, particularly when
        distributed, such as at a public event.
    \item Unpatched or outdated software may contain vulnerabilities,
        as well as normal software with recently discovered
        vulnerabilities which an attacker could exploit.
\end{itemize}

\section{Threat prevention}

\subsection{MAC Address filtering}

A \textit{MAC Address} is unique to each device. Filtering MAC
Addresses could mean only allowing authorised devices to connect to
the network (\textit{whitelisting}) or blocking certain devices from a
network (\textit{blacklisting}). However, this is bypassable through
MAC address \textit{spoofing}, where a device can appear to have a MAC
address other than its own.

\subsection{Firewall}

A firewall blocks internet activity. This may be blocking access to
certain sites, or preventing external activity from potential
attackers.

\subsection{Authentication}

Authentication is the validation of identity through credentials. The
most common form of this is through a username and password. It can
also be through physical objects such as cards (such as credit card)
and through biometric methods such as fingerprints.

CAPTCHA (tests that determine if a user is a human, such as by typing
in a word in strange font) and e-mail verification (where the user
must respond to an e-mail only they could have received) can also be
used as authentication and to ensure that the user is human and not an
automated attack.

\subsection{Encryption}

Encrypted data is encoded in such a way that only the sender and
recipient and sometimes only recipient can decode the data and read
the information. To anyone else (such as an eavesdropper), the data is
meaningless.