malwares

Malware is software designed to perform unwanted or harmful actions on a computer, device, or network. The term, a portmanteau of malicious software, is commonly used as both singular and plural; some writers use malwares as a plural form. Malware aims to compromise confidentiality, integrity, or availability of digital systems.

Common categories include viruses, which attach to legitimate programs and require execution to spread; worms, which propagate independently over networks; trojans, which disguise themselves as benign software while performing hidden actions; ransomware, which encrypts data and demands payment; spyware and adware, which monitor or display ads; rootkits, which hide malicious activity; and keyloggers or botnet software that harvest credentials or enable remote control.

Malware spreads through phishing emails, malicious attachments, drive-by downloads, compromised software updates, removable media, and supply-chain attacks. Exploiting software vulnerabilities or weak credentials also enables broader infection.

Effects range from data theft and financial loss to system disruption and surveillance. Ransomware and botnets can halt operations or steal credentials, while long-term infections may operate covertly to monitor users or harvest information.

Defenses include endpoint protection, intrusion detection, and antivirus software, along with regular patching, backups, least-privilege access, network segmentation, and user education. Prepared incident response and robust security hygiene reduce risk and help limit damage when infections occur.

Malware has evolved since the 1980s, from early self-replicating programs to modern, automated campaigns. Notable milestones include early computer viruses and later widespread ransomware and sophisticated trojans that target mobile devices and critical infrastructure.