Malware

Malware (a portmanteau of malicious software) is any software intentionally designed to cause disruption or destruction to a computer, server, client, or computer network, leak private information, gain unauthorized access to information or systems, deprive access to information, or interfere with the user's computer security and privacy without their knowledge. Researchers tend to classify malware into one or more sub-types (i.e. computer viruses, worms, Trojan horses, logic bombs, ransomware, spyware, adware, rogue software, wipers and keyloggers).

Malware poses serious threats to individuals and businesses on the Internet. According to Symantec's 2018 Internet Security Threat Report (ISTR), the number of malware variants increased to 669,947,865 in 2017, which is twice as many malware variants as in 2016. Cybercrime, which includes malware attacks as well as other crimes committed by computer, was predicted to cost the global economy US$6 trillion in 2021, and is increasing at a rate of 15% per year. Since 2021, malware has been designed to target computer systems that run critical infrastructure such as the electricity distribution network.

The defense strategies against malware differ according to its type, but most can be prevented by installing antivirus software or firewalls, applying regular patches, securing networks, creating backups, and isolating infected systems. Malware can be designed to evade antivirus software detection algorithms.