Computer Virus JSS3 Computer Studies Lesson Note

What is a Computer Virus? 

A computer virus is a type of malicious software, or malware that spreads between computers and causes damage to data and software. Computer viruses aim to disrupt systems, cause major operational issues, and result in data loss and leakage. Simply put it is a program written by a wicked programmer to cause damage to the Computer system. 

Types of Computer Virus. 

1. Boot sector virus: Boot sector viruses are a type of malware that infects a system’s boot partition or the master boot record (MBR) of a hard disk. 
2. Executable file virus: This is a computer virus that infects executable and command files of application packages. The infected applications spread the virus by infecting associated documents and other applications whenever they are opened or run. The virus is also called a file virus. 
3. Multipartite virus: A multipartite virus is a type of fast-acting malware that attacks a device’s boot sector and executable files simultaneously. Multipartite viruses are often considered more problematic than traditional computer viruses due to their ability to spread in multiple ways. 
4. Macro virus: a macro virus is a virus that is written in a macro language: a programming language that is embedded inside a software application. 

Examples of Computer Virus 

• Morris Worm virus 
• Trojan horse virus 
• Jerusalem virus 
• Christmas/25th December virus 
• Alabama virus 
• ILOVEYOU virus 
• Pin-pong virus 
• SQL Slammer virus 
• Stuxnet virus 
• CryptoLocker virus 
• Conficker virus 
• Tinba virus 
• Logic bomb virus 
• Sleeper virus etc.

  Sources Of Viruses

1. Infected Diskette 
2. Booting from infected CDROM 
3. Illegal duplication 
4. Unsecured Downloading
5. Sharing of external storage devices 
6. Infected memory card 
7. Pirated or Cracked Software. 
8. Unpatched Software. 
9. Email Attachments. 
10. Bluetooth. …etc.