Cyber Security Basics: Malware, Phishing and Staying Safe Online
The cyber security terms asked in computer tests (virus, worm, Trojan, ransomware, phishing, firewall, 2FA) explained simply, with practical safety habits.
By the World MCQ Forum Editorial Team · 27 October 2026 · 2 min read
Cyber security questions are now common in computer tests, and the knowledge is useful far beyond the exam. Most questions ask you to tell apart types of malicious software or identify a safe practice. Here are the key ideas in plain language.
Types of malware
“Malware” means malicious software. The types differ mainly in how they spread and what they do.
| Type | How it works |
|---|---|
| Virus | Attaches itself to a file or program and spreads when that file is run or shared |
| Worm | Spreads by itself across networks, without needing to attach to another file |
| Trojan horse | Pretends to be useful software, but secretly does harm once installed |
| Ransomware | Locks or encrypts your files and demands payment to unlock them |
| Spyware | Secretly collects information about your activity |
| Adware | Displays unwanted advertisements |
Exam tip: the most common question asks for the difference between a virus and a worm. A virus needs a host file; a worm spreads on its own.
Phishing
Phishing is a fake message, by email, SMS or social media, that imitates a trusted organization in order to steal passwords, bank details or one-time codes (OTPs).
Warning signs include:
- urgent or threatening language (“your account will be blocked today”)
- requests for passwords, PINs or OTP codes
- links whose web address does not match the real organization
- spelling mistakes and generic greetings
Banks and legitimate organizations do not ask for your PIN or OTP through messages.
Defences
| Defence | What it does |
|---|---|
| Firewall | Monitors network traffic and blocks unauthorized access |
| Antivirus software | Detects and removes malware |
| Two-factor authentication (2FA) | Requires a second proof of identity, such as a code on your phone, in addition to your password |
| Software updates (patches) | Fix security weaknesses that attackers could exploit |
| Encryption | Scrambles data so only authorized people can read it (HTTPS encrypts web traffic) |
| Backups | Let you restore files after ransomware or hardware failure |
Safe habits worth knowing
- Use strong, unique passwords for important accounts, and turn on 2FA where available.
- Do not open attachments or run .exe files from unknown senders.
- Check that websites asking for personal information use HTTPS.
- Keep your operating system and apps updated.
- Back up important files regularly.
Quick self-check
- Which malware spreads across networks by itself? (Worm)
- Which malware encrypts files and demands payment? (Ransomware)
- A fake bank SMS asking for your OTP is an example of what? (Phishing)
- What does 2FA add to a password? (A second form of verification)
Then practise with our Hardware, Software and Security MCQs.