Malware

Malware — short for malicious software — is any software intentionally designed to cause damage, disruption or unauthorised access to a computer system. This lesson covers the main types of malware that appear on the GCSE Computer Science specification: viruses, worms, trojans, ransomware and spyware.

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How Malware Spreads

Malware can reach a computer through many routes:

• Email attachments — an infected file disguised as a document or invoice
• Malicious websites — visiting a compromised or fake website triggers a download
• Infected USB drives — plugging in a device that carries malware
• Software downloads — downloading pirated or unofficial software
• Network vulnerabilities — exploiting unpatched flaws to spread automatically

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Viruses

A computer virus is a type of malware that attaches itself to a legitimate file or program. It only activates and spreads when the host file is opened or executed by the user.

Key Characteristics of Viruses