Malware is any malicious software, script, or code developed or used for the purpose of compromising or harming information assets without the owner’s informed consent. Examples include viruses, worms, spyware, keyloggers, backdoors, etc.
Malware can take many forms and perform multiple functions. From the Vocabulary for Event Recording and Incident Sharing (VERIS):
Malware is any malicious software, script, or code developed or used for the purpose of compromising or harming information assets without the owner’s informed consent. Examples include viruses, worms, spyware, keyloggers, backdoors, etc.
In order to compromise a system, malware may exploit vulnerabilities in software or deceive users. Alternately, an attacker may install tools to facilitate activities during an ongoing intrusion, such as back doors or information collection. The Software Engineering Institute has produced a lexicon of terms used in malware analysis.
Programmers interested in malware analysis have many resources available to assist and guide them through various stages of the process.