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Essential Terms and Concepts for Online Security


In today’s digital world, understanding cyber security terms is more important than ever, but they’re not always straightforward. Our glossary will help you navigate the complex landscape of cyber threats and defences so that you can stay safe online.



Account Harvesting 
Account harvesting is a type of cyberattack that involves the theft of user account information, such as usernames and passwords. This stolen data is often used in phishing attacks or sold on to other cyber criminals for financial gain. Account harvesting can be carried out through various techniques, such as data breaches, social engineering, or malware infections.

Software that is covertly installed on your computer and designed to deliver advertisements or other content which encourages you to purchase goods or services. 

Software that is designed to prevent infection from computer viruses.

The process of verifying a user's identity so they can gain access to an account or system. This is typically achieved through usernames, passwords, or other credentials.


A digital currency that was created in 2009 and operates on a decentralised network. It allows for direct user transactions without needing a central authority or financial institution.

A single compromised computer (a robot computer), sometimes called a zombie.

A network of compromised computers, also called a zombie network.

Botnet master 
The individual (or group) who controls a botnet remotely, also called a bot-herder.

Also known as brand hijacking, brandjacking is when a cybercriminal assumes the unauthorised use of a company, brand, or person's identity for malicious purposes. It's often used in phishing attacks, where cybercriminals pose as well-known organisations in order to convince victims to hand over sensitive information.

Brushing scam
A type of e-commerce fraud in which a seller obtains a consumer's personal information and sends unordered goods to them. Afterwards, the scammer writes fake reviews in the recipient's name to falsely boost their ratings or sales rankings.

A software application that enables the retrieval and presentation of websites and other internet resources.

Browser hijacking 
A symptom of malware infection (particularly ransomware and scareware) in which your browser persistently redirects to fraudulent websites, usually in an attempt to extort money.


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

A type of virtual currency that uses cryptography to secure and verify transactions and control the creation of new units, operating on a decentralised network without a central authority.

A ransomware strain that was first spotted in 2013 and utilised a trojan that targeted devices running Microsoft Windows. The ransomware would then encrypt a victim’s files and demand a ransom. 


A type of manipulated media that uses artificial intelligence and machine learning to create or alter video/audio content to make it seem like a person said or did something that they didn’t. They’re typically used to spread false information or for other malicious reasons. 

Denial-of-service attack (DoS) 
An attack that 'floods' a system with useless data or requests for data in order to overload it.

Dictionary attack 
When attackers attempt to guess a password and gain unauthorised access to a system by using a "password dictionary" or a lengthy list of commonly used password and character combinations. Many websites implement minimum password requirements to avoid these attacks.

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.

Distributed denial-of-service attack (DDoS) 
A denial-of-service attack coming from multiple sources at once.

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.

A program that is automatically downloaded to your computer, often without your consent or even your knowledge.


The process of transforming documents and files for safe transmission over a public network. The information is then converted or deciphered back into its original format.

Ethical hacking
A process of testing computer systems and networks for security vulnerabilities or weaknesses so that they can be patched before malicious actors exploit them.


Hardware or software that monitors information going in and out of your computer or network.

Copyrighted computer software, which is made available for use free of charge for an unlimited time.


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

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

A security mechanism that involves deliberately creating vulnerabilities on a computer system or network to attract hackers and gather information about their methods and motives. 

An area in which wi-fi is available to the general public as a wireless local area network, as in a coffee shop.


Identity theft 
Use of personal details by someone else to deceive, to support some type of crime, or even just to play a joke. Identity theft is a form of identity crime (where somebody uses a false identity to commit a crime).

Internet Service Provider (ISP) 
A company that provides access to the internet.


Keystroke logger (keylogger)
A malware program hidden on a computer that records and 'logs' each key you press. It is used to record your personal data, e.g., usernames, passwords, credit card and bank account numbers which is then sent to the malware operator without your knowledge.


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 that makes money from the exposure generated by people liking and hence sharing the page.

A type of ransomware that was first spotted in 2016. Locky used social engineering tactics before encrypting a victim’s files and demanding payment in exchange for the decryption key. 


Malicious software (Malware) 
A catch-all term used to describe software designed to be installed into a computer system for the purpose of causing harm to you or others. This would include viruses, spyware, trojans, worms, etc. 

A device that is used to connect your computer to a network (such as the internet) over a long distance.

Multi-Factor Authentication (MFA) or Two-Factor Authentication (2FA)
A security mechanism that requires users to provide two or more forms of authentication before they can gain access to a system, or account. Authentication methods include passwords, OTPs, authenticator apps, and biometrics. 


The National Institute of Standards and Technology (NIST) Cyber Security Framework (CSF). This widely used framework provides a set of standards, guidelines, and best practices for improving cybersecurity in businesses. 


One-time Password (OTP) 
A security mechanism used to authenticate users for a single login session or transaction on a digital device. The passwords are only valid for one login session and typically expire after a short time. 


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. 

Penetration testing
The process of testing a computer system or network for security vulnerabilities, often by simulating a real-world attack to identify and fix issues. 

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 websites used to gain access to personal information for illegal purposes such as transferring funds or purchasing goods over the internet. 

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.


Malware that handicaps computer functionality, e.g. through browser hijacking or encrypting personal data, and offers to restore the functionality for a fee. 

Remote access 
Communication with a computer or network from a remote location through a link such as the internet or mobile phone. 

A software system that consists of one or more programs designed to obscure the fact that a system has been compromised.

A device that connects a local network to the internet and converts a public IP address to private addresses on the local network.

A type of ransomware that has been in use since 2018, often in targeted attacks against large organizations, demanding large sums of money in exchange for decryption.


A commonly used term to describe a confidence trick, relying on email or a website to deliver the trick to unsuspecting users. 

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. 

Security symbols 
A secure webpage will have two symbols - a closed padlock image at the top or bottom of the browser window (although this may not be visible on a mobile device), and 'https://' in the address bar. Modern browsers also colour code the address bar to provide a visual cue that the page is secure. These signs help to indicate the presence of a digital certificate, which can provide a way for you to verify the identity and authenticity of a website. 

Service Set Identifiers (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. 

Secure Socket Layer (SSL) 
The most widely used security protocol on the internet, used for online banking and shopping sites. Website digital certificates are commonly implemented through SSL. The presence of 'https' in the browser address bar demonstrates that the connection between your computer and the website is encrypted. However, 'https' can still be present when connecting to a website with an invalid digital certificate.

Short for ‘SMS phishing’, smishing attacks use text messages to trick recipients into giving away sensitive information or downloading malware onto their devices.

Social engineering 
Psychological manipulation of people in order to achieve a hidden goal. A wide variety of social engineering techniques are used in activities such as fraud, phishing and like farming. 

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 
An email spoofing fraud attempt (phishing) that targets a specific organisation, seeking unauthorised access to confidential data. 

Software that is covertly installed on a computing device and takes information from it without your consent or the knowledge of the user.

A highly sophisticated computer worm that was developed by U.S. and Israeli intelligence in 2010 to sabotage Iran’s nuclear program. 

Supply chain attack
A type of cyberattack that targets an organisation by exploiting vulnerabilities in the weaker links of its supply chain, often by infecting the software or hardware that they use. 


Trojan horse 
Malicious code that is hidden in a computer program or file that may appear to be useful, interesting, or at the very least harmless to you when using your computer. When this computer program or file is run, the malicious code is also triggered, resulting in the set up or installation of malware.

TrickBot / TrickLoader
A banking trojan that targets consumers and businesses and steals sensitive financial information, such as account credentials, credit card numbers, banking information, personally identifiable information (PII), and even cryptocurrency. 


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 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. 

Also known as voice phishing, in these attacks, scammers will use voice messages or phone calls and apply social engineering tactics to steal personal information from a victim. 

The routing of real-time voice conversations (telephone calls) over the internet rather than over an analogue or circuit-switched network.


A strain of ransomware that rapidly spread on Windows operating systems in May 2017, causing a global cybersecurity epidemic, with damages costing victims billions of dollars. 

Watering hole
In a watering hole attack, a cybercriminal identifies a website that is regularly visited by a specific group of users, such as an organisation or industry sector. The attacker then compromises the website so that it will infect visitor’s devices with malware. 

Whaling is a type of email fraud targeting high-profile end users like C-level corporate executives. 

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


A compromised computer. See Bot.