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Account harvesting

The illegal practice of collecting email accounts from information in the public domain or by using software to search for email addresses stored locally on a computer. Account harvesting may be used for spamming.


Software that is used to display advertising. This type of software may be considered potentially unwanted as it may offer some kind of service, or inducement to users in return for displaying ads.


Software that is used to detect, stop and remove malicious software, ideally preventing infection.

Application whitelisting

An approach in which all programs are prevented from running by default, with only an explicitly defined set of programs allowed to run.


The process of verifying the identity of a user, process or device as a prerequisite to allowing access to resources in a system.


Bitcoin and other crypto-currencies

A type of digital currency which uses encryption techniques to regulate the generation of units of currency and verify the transfer of funds, operating independently of a central bank.

Black Hat

A person that hacks for personal gain and/or who engages in illicit and unsanctioned hacking activities.


A list of entities that are not considered trustworthy and are blocked or denied access.


A program that performs automated tasks. In a cyber security context, a malware-infected computer that carries out tasks set by someone other than the device’s legitimate user.


A network of compromised computers that are used to perform malicious activities without their owner’s knowledge. This could include sending spam, spreading malware or being used in Distributed Denial of Service attacks.

Breach (data)

When data is lost or subjected to unauthorised access, modification, disclosure, or other misuse or interference. Also referred to as a ‘Data Spill’.

Breach (security)

An incident that results in unauthorised access of data, applications, services, networks and/or devices by bypassing their underlying security mechanisms.


A software application for retrieving, presenting and traversing information resources on the world wide web.

Browser hijacking

Occurs when your browser settings are changed without your knowledge or consent. Your browser may persistently redirect to malicious or other unwanted websites.


An unexpected and relatively small defect, fault, flaw, or imperfection in an information system or device.

BYOD (Bring Your Own Device)

A policy used by organisations where employees are allowed to bring and use their own devices (e.g. laptop, mobile phone, etc. ) for work.



Internet predators who create fake online identities to lure people into emotional or romantic relationships for personal or financial gain.

Cloud computing

Where computer resources, such as software applications and storage are hosted remotely (in the cloud) and accessed as a service online. This differs from more traditional computing models where these resources might be hosted on your local computer or on a local network.


A string of text stored by your web browser enabling a website to remember you and your personal settings.


A particularly malicious type of ransomware which, once installed on your computer, encrypts and locks all of the files on the infected computer including documents, photos, music and video. A pop up window will then display on the computer screen requesting payment of a ransom in return for a CryptoLocker key to unlock the encrypted files. Paying the ransom does not guarantee removal of the CryptoLocker.

Cyber attack

A malicious attempt to damage, destroy or disrupt data and computer systems or networks. Note that while these attacks occur using ‘cyber’ or online means, they can have physical or real world consequences.


Crimes directed at computers, such as illegally modifying electronic data or seeking a ransom to unlock a computer affected by malicious software. It also includes crimes where computers facilitate an existing offence, such as online fraud or online child sex offences.

Cyber event

An identified occurrence of a system, service or network state indicating a possible breach of information security policy or failure of safeguards, or a previously unknown situation that may be security relevant.

Cyber security

Measures relating to the confidentiality, availability and integrity of information that is processed, stored and communicated by electronic or similar means.


The environment formed by physical and non-physical components to store, modify, and exchange data using computer networks.

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Dark web

The dark web is made up of sites that are not indexed by search engines and are only accessible through specialty networks such as The Onion Router (ToR). Often, the dark web is used by website operators who want to remain anonymous. The ‘Dark Web’ is a subset of the ‘Deep Web’.

Data Breach

The unauthorized movement or disclosure of sensitive private or business information.


The decoding of encrypted messages

Denial-of-Service (DoS)

An attack that is used to stop an online system (such as a website) from being available to legitimate users. These attacks often flood targeted systems with requests until they are unable to respond.

Dictionary attack

Where attackers use ‘password dictionaries’ or long lists of the most commonly-used passwords and character combinations against a password in order to guess it and break into a system.

Digital certificate

A way for browsers to verify the identity and authenticity of a website. A digital certificate is issued to a website by a trusted third party certificate authority.

Digital footprint

The ‘footprint’ of digital information that you leave behind when performing activities online. This activity can include almost anything you do on the web, including searching for information, following links, or liking items on social media platforms.

Digital signature

A process that verifies the source of the data and the integrity of the associated data.

Distributed denial-of-service attack (DDoS)

A coordinated denial of service attack coming from multiple computers at the same time.

Domain Name System (DNS)

A hierarchical naming system for resources connected to the internet. The DNS translates domain names to numerical identifiers (IP addresses) which are readable to networking equipment, allowing the routing of data from one point on the internet to another.

Drive-by download

When an unsuspecting user is compromised by visiting a website that contains malicious code. Often, these types of attack attempt to exploit vulnerabilities in order to install malicious software without the user’s interaction or knowledge.



The process of protecting information by making it unreadable to everyone apart from to those for whom it is intended. The information can only be decoded by recipients who have the correct secret ‘key’.


A way to access or adversely affect a computer system by taking advantage of a vulnerability. Exploits typically consist of malicious code and may be run against unsuspecting users when they visit compromised or malicious websites (as in a <link>drive-by download</link>) or when they inadvertently run malicious software.



Hardware or software which monitors information going in and out of your computer or network in order to prevent unauthorised access.



The unauthorised exploitation of weaknesses in a computer system or network.


Someone who attempts to gain unauthorized access to a computer system, often for fraudulent purposes.


The mechanical parts of a computer system, including the central processing unit, monitor, keyboard, and mouse, as well as other equipment like printers and speakers and mobile devices such as tablets and smart phones.


An area where wireless internet access is available to the general public.

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Identity theft

Where a victim’s personal details are stolen and used to perpetrate crime – commonly fraud. Identity theft is a serious crime and can result in long term and far-reaching negative consequences for victims.

Internet of Things (IoT)

Where everyday physical objects, such as fridges, televisions are identified, labelled and connected to the internet.

Internet Service Provider (ISP)

A company that provides subscribers with access to the internet.


A mobile operating system created and developed by Apple, designed primarily for mobile devices such as tablets and smartphones.

IP Address

Also known as an “IP number” or simply an “IP”, short for Internet Protocol. A code made up of a string of numbers that identifies a particular computer on the Internet. Every computer requires an IP address to connect to the Internet.


Keystroke logger (or keylogger)

Malicious software that records and 'logs' each key you press. These programs may be used to capture confidential information (such as login or financial details) and send to an attacker.


Like farming

Use of social engineering, such as compelling stories or photos, to persuade large number of users to 'like' a social networking page. Many of the stories are fake, and are part of a scam which makes money from the exposure generated by people liking and hence sharing the page.



The use of online advertising to spread malware. Malvertising involves injecting malicious or malware-laden advertisements into legitimate online advertising networks and webpages.


Small programs that automate common tasks in Microsoft Office documents. Macros may be used by attackers to run malicious code hidden in Office documents.

Malicious software (malware)

A catch-all term used to describe software that may be used to cause harm to you or others. Types of malicious software includes viruses, trojans, worms, keyloggers, etc.

Multi-factor authentication

A method of computer access control in which a user is granted access only after successfully presenting several separate pieces of evidence to an authentication mechanism. It typically includes at least two of the following categories: knowledge (something they know), possession (something they have), and inherence (something they are).

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Operating System

Also known as an “OS,” this is the software that communicates with computer hardware on the most basic level. Without an operating system, no software programs can run. The OS is what allocates memory, processes tasks, accesses disks and peripherials, and serves as the user interface.


Padlock (https://)

A padlock display in a browser is intended to indicate a secure connection or website, although it may not always be a reliable indicator. Users should look instead for ‘HTTPS’ at the beginning of the address bar and check the website’s SSL certificate.


A secret word, phrase or series of characters that is used for authentication.


A fix for a software program, also known as a software update.

Peer-to-peer file sharing network (P2P)

A decentralised file sharing system. Files are stored on and served by the personal computers of the users.


A way of harvesting personal information, where a hacker puts a malicious code on your computer that redirects you to a fake site.

Phishing (email/website)

Fraudulent email messages or web sites used to gain access to personal information for illegal purposes such as transferring funds or purchasing goods over the internet.


A small window, which suddenly appears (pops-up) in the foreground of the normal screen.

Potentially Unwanted Software (PUS)

Also known as Potentially Unwanted Applications (PUA). These are applications that may appear to serve a useful purpose, but often perform actions that may adversely affect a computer’s performance.

Privacy settings

Settings which control how a user's data is shared with other people or systems. Privacy settings apply to web browsers and social networking services.

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Malicious software that makes a computer or its data unusable until the victim pays a fee. Ransomware is used to perpetrate extortion against individuals and organisations.

Remote access

Access to a computer or network from a remote location as opposed to by physical proximity.


A tool or set of tools used by an attacker in order to compromise a system, gain the highest level of privilege, and then hide their activity.



Malware that causes frightening messages to appear (for example, that your computer is infected with malware or that you are guilty of a crime), and attempts to extort money from you to resolve the alleged issue. Similar to ransomware.

Secure Socket Layer (SSL)

The most widely used security protocol on the internet, used for online banking and shopping sites. The presence of 'https' in the browser address bar demonstrates that the connection between your computer and the website is encrypted.

Service Set Identifier (SSID)

The Service Set Identifier (SSID) is the name given to identify a particular wi-fi network. The SSID is broadcast by the wireless access point (wireless router) and can be detected by other wireless-enabled devices in range of the wireless access point. In some cases SSIDs are hidden, making them invisible to wi-fi clients.

Social engineering

The act of manipulating victims into performing an action of the attacker’s choice. Actions might include running a malicious program or revealing sensitive information, such as login details.


Unsolicited email. Most spam is commercial advertising, often for dubious products, get-rich-quick schemes, or illegal services. Users are advised that if an offer in an email appears too good to be true then it probably is and should not be actioned in any way.

Spear phishing

A form of <link>phishing</link> where a message is specifically crafted to target individuals from a particular organisation.  Victims may be more likely to respond to these messages because they appear to be more authentic or from a known and trusted source.


A program that collects information on the user’s activities without their consent. Spyware may be installed on a system illegitimately, or as a part of other software without the user’s knowledge.



Traditionally, a program that may appear to be useful but activates a malicious payload when run. Trojans are differentiated from other types of malware by their inability to spread independently.

Two-factor authentication

Also known as multi-factor authentication, this is where a user must provide more than one type of proof that they are authorised before they can access a system. For example, a user might need to provide something they know – such as a password – as well as something they have – such as a token.

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Universal Resource Locator. The technical term for the address (location) of an internet resource on the internet such as a website or image within a website.

USB (Universal Serial Bus) stick

Universal Serial Bus. A small piece of hardware that stores data, sometimes called a jump drive, thumb drive or flash drive.



Malware designed to infect and corrupt a computer and to copy itself. Viruses can disrupt programs installed on a computer.


A weakness (that may be an unintended consequence of design or configuration) that can be exploited by attackers to compromise or otherwise adversely affect a computer system.


Watering hole attack

An attack where a fake website (or a compromised real one) is used to exploit visiting users.


A whitelist is a list of known-good software that is allowed to run on a computer system.  Importantly, this means that anything that isn’t on the whitelist – including malware – won’t be able to run and potentially damage the system.


A set of wireless communication protocols that can transmit traffic to wi-fi-enabled devices within a local area. A wi-fi-enabled device such as a laptop or mobile device can connect to the internet when within range of a wireless network connected to the internet. An area covered by one or more wi-fi access points is commonly called a hotspot.


A self-replicating virus that does not alter files but resides in active memory and duplicates itself.



A recently discovered vulnerability or bug in software that is unknown to the vendor and can be exploited by attackers.

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