Learn the terms
Security Glossary
Plain-language definitions of the phishing and cybersecurity terms you'll come across on this site and elsewhere, grouped by category and alphabetized within each.
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Attacks & Social Engineering
Business Email Compromise (BEC)
A scam where an attacker impersonates an executive or trusted vendor by email to trick an employee into making a fraudulent payment or sharing sensitive data.
Credential Harvesting
Tricking someone into entering their username and password into a fake login page so the attacker can steal and reuse them.
Homoglyph / IDN Homograph Attack
Registering a domain using look-alike characters from another alphabet (for example, a Cyrillic "а" instead of a Latin "a") so it visually resembles a trusted domain. Our Homoglyph Checker tool detects these.
Man-in-the-Middle (MITM) Attack
An attacker secretly intercepts, and potentially alters, communication between two parties who believe they are talking directly to each other.
Pharming
Redirecting a victim to a fraudulent website even when they typed the correct address, usually by tampering with DNS resolution rather than tricking them into clicking a bad link.
Phishing
A scam that impersonates a trusted person or organization — typically by email, text, or a fake website — to trick someone into revealing sensitive information or installing malware.
Pretexting
Inventing a false scenario (a "pretext") — such as posing as IT support or a bank employee — to manipulate someone into handing over information or access.
Quishing (QR Code Phishing)
Phishing carried out through a malicious QR code that leads to a fake login page or triggers a malicious download when scanned.
Session Hijacking
Stealing or predicting a victim's valid session token to impersonate them as a logged-in user without ever needing their password.
Smishing
Phishing carried out over SMS text messages, often impersonating delivery services, banks, or government agencies.
Social Engineering
Manipulating people, rather than exploiting technical flaws, to gain access, information, or money — phishing, vishing, and pretexting are all forms of it.
Spear Phishing
A phishing attempt personalized and targeted at a specific individual or organization, using researched details to appear more convincing than a generic phishing message.
Typosquatting
Registering a domain that's a common misspelling or slight variation of a popular website (for example, gooogle.com) to catch visitors who mistype the real address.
Vishing
Phishing carried out over a phone call, often impersonating a bank, government agency, or tech support to pressure the victim into acting quickly.
Watering Hole Attack
Compromising a website that a specific target group is known to visit, so that visiting the legitimate-looking site itself delivers the attack.
Whaling
A spear-phishing attack specifically aimed at senior executives or other high-value targets within an organization.
Malware
Botnet
A network of malware-infected devices ("bots") controlled remotely, often used together to send spam, launch attacks, or mine cryptocurrency without their owners' knowledge.
Command and Control (C2)
The infrastructure attackers use to remotely communicate with and issue instructions to malware already running on a compromised device.
Drive-by Download
Malware that installs itself automatically just from visiting a compromised or malicious webpage, without the victim clicking or downloading anything intentionally.
Keylogger
Malware or hardware that secretly records every keystroke a victim types, often used to steal passwords and other sensitive information.
Malware
Short for "malicious software" — any program designed to damage, disrupt, or gain unauthorized access to a device or network.
Payload
The part of malware that actually carries out its malicious action, such as encrypting files or stealing data, as opposed to the parts that help it spread or hide.
Ransomware
Malware that encrypts a victim's files or locks them out of their system, then demands payment in exchange for restoring access.
Rootkit
Malware designed to hide its own presence, and often that of other malware, deep within a system, making it especially hard to detect and remove.
Spyware
Software that secretly monitors a person's activity, such as browsing history or messages, and sends that information to someone else without consent.
Trojan Horse
Malware disguised as legitimate, harmless software to trick a user into installing it themselves.
Worm
Malware that spreads automatically across networks and devices without needing a user to click, open, or run anything.
Vulnerabilities & Bugs
Bug
An unintended flaw or mistake in software code that causes it to behave incorrectly. Not every bug is a security issue, but some create exploitable vulnerabilities.
Bug Bounty
A program where an organization pays security researchers for responsibly reporting vulnerabilities they find in its software.
CVE (Common Vulnerabilities and Exposures)
A publicly listed, standardized identifier (like CVE-2024-12345) assigned to a specific known vulnerability, making it easier to track and reference across different security tools and reports.
Exploit
Code or a technique that takes advantage of a specific vulnerability to make software do something its developers didn't intend, such as granting unauthorized access.
Patch
An update released by a software vendor to fix a bug or vulnerability. Installing patches promptly is one of the most effective ways to stay protected.
Proof of Concept (PoC)
A minimal demonstration that a vulnerability is genuinely exploitable, used by researchers to prove a flaw is real without necessarily causing harm.
Responsible Disclosure
The practice of privately reporting a discovered vulnerability to the affected organization and giving them time to fix it before any public details are released.
Security Advisory
An official notice from a vendor or security organization describing a vulnerability, its severity, and how to protect against or fix it.
Vulnerability
A weakness in software, hardware, or a process that could be exploited to cause harm, such as unauthorized access or data exposure.
Zero-Day Vulnerability
A software flaw that is exploited by attackers before the vendor has released a fix — "zero days" of warning to patch it.
Defense & Response
Endpoint Detection and Response (EDR)
Security software that continuously monitors individual devices for suspicious activity and can automatically respond to contain a threat.
Firewall
A security system, in hardware or software, that monitors and controls network traffic based on a set of rules, blocking unauthorized access.
Indicator of Compromise (IOC)
A piece of forensic evidence — a file hash, IP address, domain, or similar — that suggests a system has been breached or targeted.
Multi-Factor Authentication (MFA)
Requiring more than one form of proof to log in — typically a password plus a code, app prompt, or hardware key — so a stolen password alone isn't enough to break in.
Sandboxing
Running an untrusted file or link in an isolated environment so any malicious behavior can be observed safely, without risking the real device or network.
SPF / DKIM / DMARC
Three email authentication standards that let a receiving mail server verify a message really came from the domain it claims to, making it harder to spoof a sender's address.
Threat Intelligence
Information about current and emerging threats — such as active attacker tactics, malicious domains, or known malware — used to anticipate and defend against attacks.
General
Data Breach
An incident where sensitive, protected, or confidential information is accessed, stolen, or exposed without authorization.
Defanging
Rewriting a malicious URL, IP address, or email address (for example, hxxp[://]evil[.]com) so it can be shared or discussed without being clickable or auto-linked.
Doxxing
Publicly revealing someone's private personal information — such as their home address or real identity — without their consent, usually with malicious intent.