Computer viruses generally operate through four distinct phases:
A computer virus is a specific type of malicious software () designed to replicate itself by inserting its own code into other programs, files, or the operating system. Much like a biological virus needs a living cell to reproduce, a digital virus requires a host program and typically some form of user action to activate and spread. How a Virus Functions What Is a Computer Virus?im
: A specific event—such as a date, a time, or a user opening an infected application—triggers the "payload". What Is a Computer Virus?im