types of malware

• Malware

  Any type of harmful program that seeks to damage or gain unauthorised access to your computer system
• Virus

  • Can replicate itself and spread from system to system by attaching itself to infected files
  • Is only activated when opened by a human
  • Once activated, can change data or corrupt a system so that it stops working
• Worm

  • Can replicate itself and spread from system to system by finding weaknesses in software
  • Does not need an infected file or human interaction to spread
  • Can spread very quickly across a network once it has infiltrated it
• Trojan

  • Is a harmful program that looks like legitimate software so users are tricked into installing it
  • Secretly gives the attacker backdoor access to the system
  • Does not self replicate or infect other files
• Spyware

  • Secretly records the activities of a user on a computer
  • Aims to record usernames, passwords and credit card information
  • Passes recorded information back to the attacker to use
• Keylogger

  • Secretly records the key presses of a user on a computer
  • Aims to record usernames, passwords and credit card information
  • Can be downloaded or plugged into the USB port
• Ransomware

  • Locks files on a computer system using encryption so that a user can no longer access them
  • The attacker demands money from the victim to decrypt (unlock) the data
  • Attackers usually use digital currencies like bitcoin which makes it hard to trace them
• SQL Injection

  • When a malicious SQL query (command) is entered into a data input box on a website
  • If the website is insecure then the SQL query can trick the website into giving unauthorised access to the website's database
  • Can be used to view and edit the contents of a database or even gain administrator privileges
• DoS (Denial of Service) attack

  • When a computer repeatedly sends requests to a server to overload the system
  • A server overload will slow the system and may take websites offline temporarily
• DDoS (Distributed Denial of Service) attack


  • A coordinated attack using a botnet of infected systems to overload a server with requests
  • A botnet is a large group of devices controlled and used maliciously by an attacker
• Brute-Force Attack

  • Every possible combination is tested in order from start to finish
  • This is not a quick method but it should break the password eventually and can be sped up if multiple computer systems are used at the same time
• Social Engineering


  Tricking others into revealing their personal data by posing as a trusted source
• Data Interception

  • When data packets on a network are intercepted by a third party (e.g. a hacker) and copied to a different location than the intended destination
  • Software called packet sniffers are used to intercept and analyse data packets