1. A generic term used to describe malicious software such as viruses, Trojan horses, spyware, and malicious active content. (McAfee.com, accessed 15 Nov 2010).
2. [Malicious] software such as viruses or Trojans designed to cause damage or disruption to a computer system. (AFDD 3-13).
3. Malicious software that secretly accesses a computer system without the owner's informed consent. A general term to mean a variety of forms of hostile, intrusive, or annoying software or program code, including computer viruses, worms, Trojan horses, spyware, most rootkits, and other malicious software or program. (Wikipedia).
Source: Terms & Definitions of Interest for DoD Counterintelligence Professionals, Office of the National Counterintelligence, https://www.dni.gov/files/NCSC/documents/ci/CI_Glossary.pdf
3. Comes from the terms "malicious" and "software". Generic term for software which carries out harmful functions on a computer. This comprises amongst others viruses, worms, Trojan horses.
Source: Information Assurance Situation in Switzerland and Internationally, Reporting and Analysis Centre for Information Assurance MELANI, https://www.newsd.admin.ch/newsd/message/attachments/11945.pdf
4. Software or firmware intended to perform an unauthorized process that will have adverse impact on the confidentiality, integrity, or availability of a system. For example, a virus, worm, Trojan horse, or other code-based entity that infects a host. Spyware and some forms of adware are also examples of malware.
Source: Election Terminology Glossary - Draft, National Institute of Standards and Technology (NIST), https://pages.nist.gov/ElectionGlossary/
5. Malicious software; software designed to interfere with a computer’s normal functioning (e.g., viruses, Trojan horses, spyware) (Merriam-Webster).
Source: Independent Panel on Internet Voting, British Columbia, https://elections.bc.ca/docs/recommendations-report.pdf
6. Malicious types of software such as adware, spyware, viruses.
Source: An Investigation into Foreign Entities Who Are Targeting Servicemembers and Veterans Online, Vietnam Veterans of America, https://vva.org/wp-content/uploads/2019/09/VVA-Investigation.pdf
7. Software that compromises the operation of a system by performing an unauthorized function or process.
Source: Explore Terms: A Glossary of Common Cybersecurity Terminology, National Initiative for Cybersecurity Careers and Studies (NICCS), https://niccs.us-cert.gov/about-niccs/glossary
8. A computer program that is clandestinely placed onto a computer with the intent to compromise the privacy, accuracy, or reliability of the computer’s data, applications, or operating system.
Source: U.S. Cyberspace Solarium Commission, March 2020, https://subscriber.politicopro.com/f/?id=00000170-c638-d8f7-a7f1-f63b33510000