Knowledge Organiser: Network Security Prevention Methods
Key Terms
- Firewall: Hardware or software that filters network traffic based on security rules
- Encryption: Converting data into an unreadable format that requires a key to decode
- Multi-factor authentication (MFA): Requires two or more verification methods to log in
- Penetration testing: Authorised simulated attack to find security vulnerabilities
- Defence in depth: Using multiple overlapping layers of security
Must-Know Facts
- Firewall filters traffic using rules (source/destination address, protocol)
- Encrypted data is useless to attackers without the decryption key
- MFA three factors: something you KNOW, HAVE, and ARE
- Authentication = verifying WHO you are; authorisation = what you are ALLOWED to do
- Principle of least privilege: users only get access they need for their role
- Penetration testing uses ethical hackers with explicit permission
- HTTPS uses encryption to protect web traffic (padlock icon)
Key Concepts
- No single security measure is perfect — use multiple layers (defence in depth)
- Encryption scrambles data using a key; without the key the data cannot be read
- MFA: even if password stolen, attacker still needs second factor
- Pen testing types: black box (no knowledge), white box (full knowledge), grey box (partial)
Common Mistakes
- Confusing authentication with authorisation: Authentication verifies WHO you are; authorisation determines WHAT you can access
- Describing a firewall as "blocking all traffic": Firewalls filter traffic using rules — some traffic is allowed through
- Thinking encryption prevents attacks: Encryption protects data in transit — it does not prevent attacks happening; it makes stolen data unreadable
- Forgetting MFA needs two DIFFERENT factor types: Two passwords is not MFA — you need two different categories (something you know, have, or are)