Network security: firewalls, threats, countermeasures and encryption

Learning objectives

Evaluate how well a firewall protects a network by inspecting and filtering traffic against rules, whitelists and blacklists, stating the attacks it cannot stop and the protection that NAT adds

(HL) Describe common network vulnerabilities: distributed denial of service, insecure protocols, malware, man-in-the-middle attacks, phishing, SQL injection, cross-site scripting, unpatched software, weak authentication and zero-day exploits

(HL) Describe countermeasures including content security policies, strong password policies, DDoS mitigation, email filtering, encrypted protocols, input validation, intrusion detection and prevention systems, multifactor authentication, SSL/TLS certificates, software updates, VPNs and MAC address whitelists, and match each to the threat it reduces

Explain symmetric and asymmetric encryption, the roles of the public key and the private key, and why keys must be generated, stored and exchanged securely

Describe how a digital certificate signed by a certificate authority proves the identity of a server and allows an encrypted HTTPS connection to be set up