Cybersecurity Glossary: A-Z Terms Explained

Cybersecurity has its own vocabulary, and it can be a lot to absorb when you're just starting out. This glossary covers the core terms referenced across our tool tutorials — from Nmap and Metasploit to Hydra and Burp Suite — explained in plain English.

Jump to a letter:

A B C D E F H M N P R S V Z

A

Attack Surface: All the possible points where an unauthorized user could try to enter or extract data from a system.
Authentication: The process of verifying that someone is who they claim to be, typically through a password, token, or biometric.
Authorization: The process of determining what an authenticated user is allowed to do or access.

B

Brute Force Attack: Systematically trying every possible password combination until the correct one is found. See our Hydra tutorial for a hands-on example.
Backdoor: A hidden method of bypassing normal authentication to gain access to a system, sometimes intentionally installed by attackers after a successful compromise.

C

CVE (Common Vulnerabilities and Exposures): A publicly cataloged, unique identifier assigned to a specific known security vulnerability, allowing researchers and vendors to reference it consistently.
Credential Stuffing: Using username/password pairs stolen from one data breach to attempt logins on other, unrelated websites, relying on password reuse.
CTF (Capture The Flag): A cybersecurity competition format where participants solve security challenges to find hidden "flags," commonly used for legal, hands-on skill practice.

D

Dictionary Attack: A password-cracking method that tries words from a precompiled list (often common passwords or real words) rather than every possible combination.
DDoS (Distributed Denial of Service): An attack that floods a system with traffic from many sources at once, aiming to make it unavailable to legitimate users.

E

Encryption: The process of converting readable data into a coded form that can only be read again with the correct decryption key.
Exploit: A piece of code or technique that takes advantage of a specific vulnerability to cause unintended behavior, such as gaining unauthorized access.

F

Firewall: A network security system that monitors and controls incoming and outgoing traffic based on defined security rules.

H

Hash: A fixed-length string generated from data using a mathematical function; used to store passwords securely without saving the actual password text.
Hardening: The process of reducing a system's attack surface by disabling unnecessary services, applying patches, and tightening configurations.

M

Malware: Any software intentionally designed to cause damage, steal data, or gain unauthorized access to a system — an umbrella term covering viruses, ransomware, spyware, and more.
MFA (Multi-Factor Authentication): A security method requiring two or more independent forms of verification (e.g., password plus a code from your phone) before granting access.

N

NIST: The U.S. National Institute of Standards and Technology, which publishes widely referenced cybersecurity frameworks and password guidelines.

P

Payload: The part of an exploit that actually executes on a target after successful exploitation, such as opening a remote session.
Penetration Testing (Pen Testing): An authorized, simulated attack on a system to evaluate its security and identify exploitable weaknesses before real attackers do.
Phishing: A social engineering attack where a fake message or website tricks someone into revealing sensitive information like login credentials.
Port: A numbered communication endpoint on a device used by network services (e.g., port 443 for HTTPS). See our Nmap tutorial for how port scanning works.

R

Ransomware: Malware that encrypts a victim's files and demands payment in exchange for the decryption key.
Red Team: A group that simulates real-world attacker behavior against an organization to test its detection and response capabilities, usually contrasted with a "blue team" defending.

S

Social Engineering: Manipulating people, rather than technical systems, into giving up confidential information or performing actions that compromise security.
SOC (Security Operations Center): A team or facility responsible for continuously monitoring, detecting, and responding to security incidents within an organization.
SQL Injection: An attack technique that inserts malicious SQL code into an application's input fields to manipulate or extract data from its database.

V

Vulnerability: A weakness in a system that could potentially be exploited to compromise its security.
VPN (Virtual Private Network): A service that creates an encrypted connection over a network, often used to protect traffic on untrusted networks or mask a user's IP address.

Z

Zero-Day: A vulnerability that is unknown to the vendor and has no available patch, meaning defenders have had "zero days" to fix it before it could be exploited.