Malware diversified into File Infectors that attached to executables and Macro Viruses that targeted productivity software like Microsoft Word.
Initial programs like Creeper (1971) were experimental and self-replicating. The first PC virus, Brain (1986) , targeted boot sectors, and the Morris Worm (1988) became the first major Internet-wide incident.
Criminal intent became the primary driver. Ransomware emerged as a dominant threat, encrypting user data for profit. Sophisticated Advanced Persistent Threats (APTs) and Ransomware-as-a-Service (RaaS) models also appeared.
A Study Of Evolution of Malware and Its Orgins - ResearchGate