AQA · GCSE · Computer Science
Course version: 8525 · Version from Sept 2020
Malicious code (malware): Describe the following forms of malware:
Different forms of malware behave in different ways, and an MCQ tests whether you can match a described behaviour to the correct type.
Checked against the AQA 8525 specification (opens in a new tab) on .
- Point 4 of 7
Study notes
From the checked teaching notes for this specification point.
The idea
Different forms of malware behave in different ways, and an MCQ tests whether you can match a described behaviour to the correct type. A virus attaches itself to a legitimate file or program and spreads when that file is run. A worm spreads itself across networks without needing a host file or user action. A trojan disguises itself as legitimate software so the user installs it willingly, then carries out hidden harmful actions. Ransomware encrypts files or locks a system and demands payment for restoration. Spyware secretly collects information such as keystrokes or browsing activity. Adware displays unwanted adverts, often bundled with free software. Read the behaviour described in the option, identify the defining feature, and choose the type whose definition matches it exactly.
What earns the marks
- Describes a virus as code that attaches to a legitimate file or program and runs when that host is executed.
- Describes a worm as self-replicating malware that spreads across networks without a host file or user action.
- Describes a trojan as malware disguised as legitimate software that the user installs, after which hidden harmful actions occur.
- Describes ransomware as malware that encrypts files or locks a system and demands payment to restore access.
- Describes spyware as malware that secretly gathers information such as keystrokes or browsing habits.
- Describes adware as software that displays unwanted advertisements, often bundled with other downloads.
Common mistakes and how to put them right
Confusing a virus with a worm.
Put it right by noting that a virus needs a host file and user action to spread, whereas a worm spreads by itself across a network.
Treating a trojan as self-replicating.
Put it right by explaining that a trojan relies on deceiving the user into installing it and does not spread by itself.
Confusing ransomware with spyware.
Put it right by saying ransomware denies access to data until payment, while spyware secretly collects information.
Exam tips
- Identify the defining behaviour in the question, such as self-replication, disguise, encryption or data collection, before choosing an option.
- Reject options that describe a different malware type even if the option sounds plausible.
- Check whether the scenario mentions user action, because that helps separate a trojan or virus from a worm.
Try the lesson
The start of the Malicious code (malware): Describe the following forms of malware: lesson, made from checked teaching notes for this specification point.
Have a go first
Which description best explains what a trojan is as a form of malware?
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Malicious code (malware): Describe the following forms of malware:
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge