Morris Worm Incident

Created by Robert Tappan Morris, this self-replicating worm exploited vulnerabilities in Unix systems, infecting a significant portion of the internet (estimated 10% or more of connected machines) and bringing operations to a halt.

Significance

The Morris Worm was a watershed moment, starkly demonstrating the internet's fragility and the urgent need for robust network security measures, directly prompting the search for solutions like firewalls.