Cyber Security
🔒 Log in to trackMalware types
🔒 Log in to trackMalware is short for malicious software. It is any program made to harm, steal or spy. Exam questions ask you to match a behaviour to a name. Learn the key difference: a virus needs a host file, a worm needs none and a trojan does not copy itself.
What malware is
Malware means malicious software. It is a program written to harm a computer, steal data or spy on a user. Questions test one skill: match the behaviour to the name.
| Malware | Key behaviour |
|---|---|
| Virus | Attaches to a file or program. Spreads when the file is run. Needs a host |
| Worm | Copies itself across a network. Needs no host file |
| Trojan horse | Hides inside useful-looking software. Does not copy itself |
| Ransomware | Locks or encrypts files and demands money. WannaCry (2017) is an example |
| Spyware | Secretly collects your information and sends it out |
| Keylogger | Records every key you press, so it can catch passwords |
| Adware | Shows unwanted advertisements |
| Rootkit | Hides deep in the system and gives the attacker admin rights |
| Botnet | Many infected "zombie" machines controlled together, often for spam or DDoS |
| Logic bomb | Code that sleeps until a date or event, then does its damage |
Three pairs that exams mix
- Virus vs worm. A virus rides on a host file and waits for you to run it. A worm needs no host. It travels through the network alone.
- Trojan vs virus. A trojan never copies itself. It pretends to be useful and opens a back door from inside.
- Ransomware vs spyware. Ransomware holds your files hostage. Spyware quietly copies data and leaves everything in place.
Rule: Ask three things. Does it need a host? Does it copy itself? Does it demand money?
How malware arrives
- Infected e-mail attachments and links.
- Pirated software.
- Infected USB drives.
- Downloads from unsafe sites.
- Fake pop-ups that say "your PC is infected".
Signs of infection
- The computer runs unusually slowly.
- Files are renamed or missing.
- Programs open on their own.
- The browser home page changes.
- Pop-ups appear all the time.
Watch: One sign alone does not prove malware. Together they form the usual exam scenario.
Safe habits
Keep the operating system and antivirus updated. Do not open unknown attachments. Install software only from official sources. Take regular backups.
Example: A free game hides a program that lets a stranger control your PC. It does not copy itself. That is a trojan.
Question types you will see
Each type: how to recognise it, the method step by step, and one question to try.
Malware identification by behaviour
A short scenario describes what the program does, and its name is asked.
Find the key action: spreads, hides, locks, spies or records.
Check whether a host file is needed.
Match the action to the table.
Every malware type has one signature behaviour.
A program pretends to be a free game but secretly opens a back door. It is a:
Show solutionHide solution
It looks useful.
It hides its true purpose.
It does not copy itself, so it is a trojan.
Trojan horse
Ransomware scenarios
Files are locked and a payment is demanded.
Spot the words locked, encrypted or pay.
Name it ransomware.
Recall WannaCry (2017) as the example.
The demand for money is the clear sign.
A message says your files are encrypted and asks for payment to unlock them. This is:
Show solutionHide solution
Files are locked.
Money is demanded.
Ransomware
Spyware, keylogger and adware
The scenario says information is collected, keys are recorded or ads keep appearing.
Secret collection of information is spyware.
Recording key presses is a keylogger.
Unwanted advertisements are adware.
These three are close relatives, and the action separates them.
Which malware records every key pressed to steal passwords?
Show solutionHide solution
It records key presses.
The name says so.
Keylogger
Botnet and zombies
Many infected machines are controlled together.
Spot the words army, zombie or remote control.
Name it a botnet.
Recall that botnets often drive DDoS attacks.
A botnet is the tool behind large floods.
A network of infected computers controlled by one attacker is called a:
Show solutionHide solution
Many machines are infected.
One attacker controls them.
Botnet
Virus vs worm vs trojan
Two or three malware names are offered, and one matches the description.
Ask if it needs a host file.
Ask if it copies itself.
Virus needs a host. Worm copies alone. Trojan does not copy.
This trio is the most used exam pair.
Which malware spreads through a network without needing a host file?
Show solutionHide solution
A virus needs a host.
A trojan does not spread by itself.
A worm spreads alone.
Worm
Shortcuts that save time
A virus needs a host file. A worm needs none. A trojan copies nothing.
A program spreads across a network by itself with no host file. What is it?
Show solutionHide solution
No host file is needed.
It copies itself.
That is a worm.
Worm
If files are locked and money is demanded, it is ransomware. WannaCry in 2017 is the standard example.
Mistakes to avoid
Where most students lose marks on this subtopic.
Saying a worm needs a host file.
A virus needs a host. A worm spreads on its own.
Saying a trojan copies itself.
A trojan does not copy itself. It hides inside useful-looking software.
Calling ransomware a kind of spyware.
Ransomware locks files for money. Spyware secretly collects information.
Thinking a keylogger records the screen.
A keylogger records key presses.
Thinking one slow computer proves malware.
Slowness is only one sign. Several signs together point to malware.
Quick revision
Read this the night before the exam.
Malware is malicious software. Virus needs a host, worm needs none, trojan does not copy itself.
Ransomware locks files and demands money. WannaCry (2017) is the example.
Spyware collects information. Keylogger records key presses. Adware shows ads.
Rootkit hides and gives admin rights. Botnet is an army of zombie machines.
A logic bomb waits for a trigger date or event.
Malware arrives through attachments, pirated software, USB drives and unsafe downloads.
Practice: 17 questions
Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.
Topic test · 10 questions
Suggested time 5 min · wrong answers go to your mistake notebook automatically.