Network Security Fundamentals

Threat Actor

An intruder who gains unauthorized access to a network by exploiting vulnerabilities

Information Theft

Unauthorized access and stealing of sensitive data from a network

Data Loss and Manipulation

Unauthorized alteration, corruption, or destruction of data

Identity Theft

Using another person’s identity or credentials without permission

Disruption of Service

Preventing legitimate users from accessing network services

Vulnerability

A weakness in a system or network that can be exploited by attacks

Technological Vulnerability

Weaknesses in hardware, software, or network protocols

Configuration Vulnerability

Weaknesses caused by insecure or incorrect device settings

Security Policy Vulnerability

Weaknesses caused by missing or poorly enforced security policies

Malware

Software designed to damage, disrupt, steal, or perform unauthorized actions

Virus

Malware that attaches to programs and spreads by infecting other files or systems

Worm

Self-replicating malware that spreads without needing a host program

Trojan Horse

Malware disguised as legitimate software that relies on user interaction

Reconnaissance Attack

An attack that gathers information about systems, services, or vulnerabilities

Access Attack

An attack that gains unauthorized access to data, systems, or privileges

Denial of Service (DoS)

An attack that disables or overwhelms a system to prevent legitimate use

Distributed Denial of Service (DDoS)

A coordinated DoS attack from multiple compromised devices

Botnet

A group of infected devices controlled by an attacker to perform coordinated attacks

Defense-in-Depth

A layered security strategy using multiple security controls to protect a network

AAA (Authentication, Authorization, Accounting)

A framework for controlling access and tracking user activity

Authentication

The process of verifying a user’s identity

Authorization

The process of determining what actions a user is allowed to perform

Accounting

The process of recording user activity on a network

Firewall

A security device that controls traffic between networks based on security rules

DMZ (Demilitarized Zone)

A network segment that hosts public services while protecting the internal network

Packet Filtering Firewall

A firewall that allows or blocks traffic based on IP addresses or MAC addresses

Application Filtering Firewall

A firewall that allows or blocks traffic based on applications or port numbers

URL Filtering

A security method that blocks or allows access to websites based on URLs or keywords

Stateful Packet Inspection (SPI)

A firewall method that monitors active connections and allows only legitimate traffic

Endpoint Security

Protection of end-user devices such as laptops, desktops, and mobile devices

Cisco AutoSecure

A Cisco feature that automatically applies security hardening settings to devices

Password Security

Techniques used to create and manage strong passwords to prevent unauthorized access

Passphrase

A long password made of multiple words for stronger security

SSH (Secure Shell)

A secure protocol used for remote access and management of network devices

RSA Key

A cryptographic key used to encrypt and secure SSH communications