← WA Computer Science ATAR Unit 2

Viruses

Malware that attaches to a host file and spreads by replicating itself when a user runs the infected file

Part of: WA Computer Science ATAR Year 11 — Cyber Security — Module 33

Understanding Viruses in WA Computer Science ATAR Unit 2

What it does: Viruses require a host, such as a document or program, to attach to and spread. A virus is triggered into action when a user executes the infected file. A virus attaches itself to a host file and cannot spread without one. Antivirus software scans files for patterns matching known viruses. Viruses can damage, corrupt, or alter the data in infected files.

Common mistakes: Wrong — a virus does need a host file; it cannot replicate without one. Wrong — viruses cannot run without a host file; they always need one to attach to.

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Free printable worksheet with full answer key — or add this module to a class and your students practise it interactively.

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This module's key terms are also in a printable crossword (Modules 125–266) and word search (Modules 28–266).

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Each concept is reinforced from every angle — learned, then applied, then tested.

Learning
Duo
Does a virus need a host file to spread?
YesNo
Matches
A virus can run without any host file
↓
A virus always needs a host file to spread
Applying
Meanings
Term
Virus
Meaning
Malware that attaches to a host file and spreads by replicating itself when a user runs the infected file
Practice
A virus attaches to a host file
Testing
Gaps
A virus to a host file.
Check Answer
Spots
1A virus needs a host file.
2It replicates on its own.

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Quick Questions

1. Does a virus need a host file to spread?
A. Yes ✓
B. No
A virus attaches itself to a host file and cannot spread without one.
2. Does a virus spread only after a user runs the infected file?
A. True ✓
B. False
A virus is activated when the infected file is executed by a user.
3. Can a virus replicate itself?
A. No
B. Yes ✓
Once activated, a virus copies itself to spread to other files or systems.
4. Can a virus run without ever being attached to a file?
A. True
B. False ✓
A virus must be attached to a host file to function and spread.
5. Can antivirus software detect known viruses?
A. Yes ✓
B. No
Antivirus software scans files for patterns matching known viruses.

Match the Pairs

Virus → Malware that attaches to a host file and replicates when run
Infected executable file → A program a virus has attached itself to
A virus needs a host file to spread → A virus attaching itself to a document macro
A virus activates when the infected file runs → A user opening an infected attachment
A virus can run without any host file → A virus always needs a host file to spread
Antivirus software cannot detect viruses → Antivirus software can detect known viruses

Key Term

Virus
Malware that attaches to a host file and spreads by replicating itself when a user runs the infected file

Fill in the Blanks

1. A virus attaches to a host file.
Hint: Type the word for how a virus attaches itself to a file.
2. It spreads when a user runs it.
Hint: Type the word meaning to move to other files or systems.
3. A virus needs a host program.
Hint: Type the word meaning to require something to function.
4. Viruses replicate when executed.
Hint: Type the word meaning to make copies of itself.
5. Antivirus scans can detect viruses.
Hint: Type the word meaning to identify or find something.

Spot the Error

Question 1
A A virus needs a host file.
B It replicates on its own.
C It spreads when executed.
Line A — Wrong — a virus does need a host file; it cannot replicate without one.
Question 2
A Viruses attach to programs.
B They run without any host.
C They spread when executed.
Line B — Wrong — viruses cannot run without a host file; they always need one to attach to.
Question 3
A A virus needs user action.
B It can corrupt or copy itself.
C Antivirus can detect viruses.
Line C — Wrong — a virus corrupts and replicates itself, it does not just copy files unrelated to itself.
Question 4
A Viruses attach to files.
B They replicate when run.
C Worms need no host file.
D They cannot damage data.
Line D — Wrong — viruses can damage or corrupt the files and data they infect.
Question 5
A A virus infects a host.
B It needs a program to run.
C It spreads with no user help.
D Antivirus can detect it.
Line C — Wrong — a virus needs a user to run the infected file; it does not spread with no user help.

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