Network Security

At A-Level you must understand the threats to networked systems and the security measures used to protect them. This lesson covers firewalls, proxy servers, intrusion detection and prevention systems (IDS/IPS), and other key network security concepts.

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Common Network Threats

Threat	Description
Malware	Malicious software — viruses, worms, Trojans, ransomware, spyware
Phishing	Fraudulent emails/websites designed to trick users into revealing credentials
Man-in-the-middle (MITM)	An attacker intercepts and possibly alters communication between two parties
Denial of Service (DoS / DDoS)	Flooding a server with traffic to make it unavailable to legitimate users
SQL injection	Inserting malicious SQL into input fields to manipulate a database
Brute force	Systematically trying all possible passwords until the correct one is found
Social engineering	Manipulating people into breaking security procedures
Packet sniffing	Capturing and analysing network traffic to extract sensitive data

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Firewalls

A firewall is a network security device (hardware or software) that monitors and controls incoming and outgoing network traffic based on a set of predefined rules.

Types of Firewall