Cambridge IGCSE 0478 · Topic 5 · 5.2a

Internet Security
Threats

Malware · Phishing · Hacking · DoS · Social Engineering · Pharming

CSZoneCambridge IGCSE Computer Science 0478

Malware Types

Malicious Software

Virus: attaches to files; spreads when files are opened/shared; can corrupt or delete data

Worm: self-replicates across networks without user action; consumes bandwidth and resources

Trojan horse: appears legitimate but contains hidden malicious code — creates backdoor for hackers

Ransomware: encrypts user's files; demands payment for decryption key (e.g. WannaCry)

Spyware: secretly collects user data (keystrokes, passwords, browsing history)

Phishing & Social Engineering

Tricking People

Phishing: fraudulent emails/messages pretending to be from trusted organisations. Goal: trick user into revealing passwords, card numbers, or clicking malicious links.

Social engineering: manipulating people psychologically rather than exploiting technical vulnerabilities. Includes impersonating tech support, creating urgency.

Pharming: redirects users from legitimate websites to fake ones by corrupting DNS records or modifying the hosts file.

DoS & Hacking

Disruption & Unauthorised Access

DoS (Denial of Service): floods a server with requests until it crashes. DDoS uses many compromised computers (botnet) simultaneously.

Hacking (unauthorised access): exploiting vulnerabilities to access systems, steal data, or disrupt services. Can be white hat (ethical) or malicious.

Man-in-the-middle attack: attacker intercepts communication between two parties to steal or alter data

Exam Practice

Have a go at this question

Cambridge IGCSE 0478 style

Describe how a phishing attack works and explain one way a user can identify a phishing email.

4 marks

An email is sent pretending to be from a trusted organisation (e.g. a bank) [1] asking the user to click a link or provide personal details [1]. Users can identify phishing by: checking if the sender's email address matches the real domain [1], or hovering over links to see if the URL destination looks suspicious [1].

Key Takeaways

What to Remember

Malware: virus (spreads via files), worm (self-replicates), Trojan (hidden), ransomware (encrypts), spyware (monitors)

Phishing: fake emails to steal credentials; Social engineering: psychological manipulation

DoS: floods server to crash it; DDoS: same but from many devices (botnet)

Pharming: corrupts DNS to redirect to fake websites