The difference between a virus and malware lies in their definitions and behavior. A virus is a specific type of malware designed to attach itself to legitimate programs and replicate when executed, spreading from one computer to another. Conversely, malware is a broader term that encompasses various harmful software types, including viruses, worms, Trojans, ransomware, and spyware. While all viruses are malware, not all malware is classified as a virus. Understanding these distinctions is crucial for developing effective security measures.