This mini-lesson covers OCR J277 · 1.4 Network security: the main threats — malware, social engineering, phishing, brute-force attacks, denial of service, data interception and SQL injection — and how to prevent them with firewalls, encryption, MAC filtering, anti-malware, physical security and penetration testing.
Answer the questions as you go and collect ⭐ stars. Press Start when you're ready.
Threats · malware
Malware
Malware (malicious software) is any program written to harm or gain access to a system. Common types:
Virus — attaches to a file and spreads when that file is opened.
Worm — self-replicates and spreads across a network without a host file.
Trojan — disguised as useful software; opens a back door once run.
Spyware — secretly records what you do (e.g. keylogging passwords).
Ransomware — encrypts your files and demands payment to unlock them.
Prevent: install anti-malware/antivirus, keep software patched/updated, and don't open suspicious attachments.
Threats · people
Social engineering, phishing & brute force
Not all attacks are technical — many target people:
Social engineering — tricking people into giving away information or access (e.g. pretending to be IT support).
Phishing — fake emails/messages/websites that look genuine to trick you into entering passwords or bank details.
Brute-force attack — automatically trying many passwords until the right one is found.
Denial of Service (DoS) — flooding a server with so many requests that it cannot respond to genuine users.
Prevent people-based attacks: staff training, strong/unique passwords, spotting suspicious messages, and locking accounts after failed logins.
Quick check
Which attack is this?
?An email pretending to be from your bank asks you to 'confirm your password' on a fake login page. What is this?
Threats · data & databases
Data interception & SQL injection
Two more threats to know:
Data interception (theft) — attackers capture data as it travels across a network (e.g. packet sniffing on open Wi-Fi) to steal passwords or personal data.
SQL injection — typing malicious SQL code into an input box (e.g. a login field) so it runs on the database, letting an attacker read, change or delete data.
Prevent:encrypt data so intercepted traffic is unreadable; validate inputs so SQL injection code is rejected.
Quick check
Why encrypt?
?Data sent over public Wi-Fi could be intercepted. How does encryption protect it?
Prevention
Preventing vulnerabilities
Layers of defence protect a network:
Firewall — monitors and controls incoming/outgoing traffic, blocking unauthorised access.
Encryption — scrambles data so intercepted data is unreadable.
MAC address filtering — only lets known devices (by MAC address) join the network.
Anti-malware software — detects, blocks and removes malware.
Physical security — locks, guards and locked server rooms to protect hardware.
Penetration testing — ethical hackers deliberately attack the system to find weaknesses before criminals do.
User access levels & strong passwords limit what each user can reach.
Quick check
Which defence?
?A company wants to find weaknesses in its own network before criminals do, by paying ethical hackers to attack it. What is this called?
Quick check
Stop unknown devices
?A network admin wants to allow only specific, known devices to connect to the Wi-Fi. Which method uses each device's unique hardware address to do this?
Sort it
Threat or defence?
Tap an item, then tap the group it belongs to.
☠️ Threat
🛡️ Defence
🔒 Network defence
Match it
Match the defence to the threat
Tap a prevention method on the left, then the threat it best tackles on the right.