A virus is a program that attaches itself to a program or file. This allows it to spread across networks and cause damage to software and hardware.

Acomputer virusismalicious software (malware)that replicates itself by attaching to

legitimateprograms or files. Once activated, viruses can:

Corrupt or delete files.

Spread across networks, infecting multiple systems.

Cause performance issuesor even render a system inoperable.

Unlikeworms, which can spread independently, viruses requirehuman action(e.g., opening an

infected file or running an executable).

Reference:McAfee Institute CCII Cyber Threat Guide, Cybercrime Encyclopedia.