Virus

A computer virus is a type of malware that attaches itself to legitimate programs or files and spreads when those infected files are executed or shared. Like biological viruses, computer viruses need a host (a file or program) and require user action (opening the infected file) to activate and spread.

Viruses can cause various types of damage — corrupting data, stealing information, consuming system resources, or providing backdoor access to attackers. While worms and ransomware dominate headlines today, viruses remain a persistent threat, particularly through infected email attachments and downloaded files.