Definition(s)
Virus
A computer program that can replicate itself, infect a computer without permission or knowledge of the user, and then spread or propagate to another computer.
Adapted from: CNSSI 4009.
Source: NICCS™ Portal Cybersecurity Lexicon, National Initiative for Cybersecurity Careers and Studies (https://niccs.us-cert.gov/glossary) as of 11 November 2015, Global Standards
Virus
Self-replicating or self-reproducing program that spreads by inserting copies of itself into other executable code or documents.
Source: ANSI/ISA–99.00.01–2007, Security for Industrial Automation and Control Systems, Part 1: Terminology, Concepts, and Models, 29 October 2007. National Standard