Topic 5 · The internet and its uses
Cyber security threats and solutions
Brute force, interception, DDoS, hacking, malware, phishing, pharming, and social engineering, and the ways to defend against them.
Threats
Cyber security means protecting systems and data from attack. These are the threats you need to know:
| Threat | What happens | Aim |
|---|---|---|
| Brute-force attack | Software tries every possible password until one works | Get into an account |
| Data interception | Data is captured as it travels across a network, for example with a packet sniffer | Steal data |
| DDoS attack | Many infected computers (a botnet) flood a server with requests so it cannot respond | Take a website offline |
| Hacking | Gaining unauthorised access to a computer system | Steal, change, or delete data |
| Malware | Malicious software: see below | Damage, steal, or extort |
| Phishing | A fake email or message tricks you into clicking a link and entering personal details | Steal details |
| Pharming | Malicious code redirects you from a real website to a fake one, even if you type the correct URL | Steal details |
| Social engineering | Manipulating people into giving away information or access, such as pretending to be IT support | Get past security by tricking people |
Types of malware
| Malware | Behaviour |
|---|---|
| Virus | Attaches to a file and replicates when the file is run, spreading to other files |
| Worm | Replicates and spreads across a network by itself, without a host file |
| Trojan horse | Pretends to be useful software but carries hidden malicious code |
| Spyware | Secretly records what you do and sends it to a third party |
| Adware | Shows unwanted adverts, often redirecting your browser |
| Ransomware | Encrypts your files and demands payment for the key |
Solutions
No single measure stops everything, so systems use several layers of protection:
| Solution | How it helps |
|---|---|
| Access levels | Users can only see and change the data they need |
| Anti-malware | Scans files for known malware, quarantines and deletes it |
| Authentication | Strong passwords, biometrics (fingerprint, face), and two-step verification (a code sent to your phone) |
| Automating software updates | Fixes security weaknesses as soon as patches are released |
| Checking emails and URLs | Spelling mistakes, odd tone, or a slightly wrong web address are signs of phishing |
| Firewall | Monitors traffic in and out of a network and blocks anything that breaks its rules |
| Privacy settings | Control who can see your information online |
| Proxy server | Sits between users and the internet, hiding their IP addresses and filtering traffic |
| SSL / TLS | Encrypts data between a browser and a server |
Exam tip. Exam questions often describe a scenario. Name the threat, explain what it does in that scenario, then give a matching solution.
Key terms
- Malware
- Software designed to harm a computer system or its users.
- Phishing
- Fraudulent messages that trick people into revealing personal information.
- Pharming
- Redirecting users from a genuine website to a fake one.
- Firewall
- Hardware or software that monitors and filters network traffic.
- Two-step verification
- Authentication that needs a second step, such as a code sent to a phone.
Check yourself
What is the difference between phishing and pharming?Show answer
Phishing tricks you into clicking a link in a fake message. Pharming redirects you to a fake site even when you type the real address, using malicious code.
How does a DDoS attack stop a website working?Show answer
A botnet sends so many requests that the server cannot cope and cannot respond to genuine users.
Give two ways to reduce the risk of a brute-force attack.Show answer
Use long, complex passwords; lock the account after a number of failed attempts; use two-step verification.