Lesson Objective
Define the term malware, explain how it can be protected against and describe the following forms of malware:
- Virus
- Trojan
- Spyware
- Adware
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KS3, GCSE, A-Level Computing Resources
Lesson 3. Malicious Code
Lesson Notes
Malware?
Malware, short for malicious software, refers to any intrusive software developed by cybercriminals (often called hackers) to steal data and damage or destroy computers and computer systems. Examples of common malware include viruses, worms, Trojan viruses, spyware, adware, and ransomware.
Here are some telltale signs that you might have malware on your system:
- Computer performance slows down significantly.
- Unexpected pop-up ads.
- Stolen, alterd or deleted data.
1. Viruses
A virus is a type of malware that attaches itself to legitimate programs or files. When these infected files are executed, the virus spreads and replicates, often causing damage to data or system files. Viruses can spread through infected email attachments, removable storage devices, or malicious websites.
2. Trojan Horse
Named after the ancient Greek story of the wooden horse used to infiltrate Troy, Trojans are deceptive programs. They appear harmless or useful but hide malicious code. Unlike viruses, Trojans don't self-replicate. Instead, they rely on user actions (such as downloading a fake app) to spread.
3. Spyware
Spyware is designed to secretly monitor a user's activities without their knowledge. It can track keystrokes, capture screenshots, record browsing history, and steal sensitive information like passwords or credit card details. Spyware often infiltrates systems through malicious downloads or compromised websites.
4. Adware
Adware is less harmful but annoying. It displays unwanted advertisements (pop-ups, banners, or redirects) to generate revenue for the attacker. While not as destructive as other malware, adware can slow down your system and disrupt your browsing experience.
5. Ransomware
Ransomware is particularly malicious. It encrypts your files or locks you out of your system, demanding a ransom (usually in cryptocurrency) to restore access The infamous WannaCry attack is an example of ransomware that affected thousands of computers worldwide.
6. Rootkit
A rootkit is a type of malicious software (malware) designed to gain unauthorized access to a computer system and maintain control over it while remaining hidden from the user or system administrators. A rootkit provides an attacker with a backdoor into an infected machine, granting them access to the computer.