Malware is a term used for any software used to disrupt computer operations, infiltrate private computers, steal sensitive data, or display unwanted advertising.
The umbrella term for malicious software was initially called a computer virus, before Yisrael Radai coined the phrase malware in 1990. The term can be used to refer a variety of hostile or intrusive software, such as viruses, worms, Trojan horses, ransomware, spyware, scareware and adware.
Early malicious software, including the first Internet worm, were designed as experiments or pranks, but this has evolved to today where governments and skilled hackers deploy malware to steal sensitive data or disrupt operations.
Malware is predominantly used for criminal purposes, but there have been examples of when malware was used for sabotage. These acts of sabotage rarely benefit the hackers or those who deploy the software, instead causing mass disruption or deletion of huge amounts of data.