When a potentially major security flaw gets announced, we cant be sure its a big one that would attack or compromise the majority of the computers in the world or your enterprise. The Robert Morris worm of 1988 infected around 6,000 computers. Since then, far bigger and faster-spreading worms appeared, most notably Michelangelo, Code Red, Melissa, SQL Slammer, ILoveYou, and Blaster. Many of the hacks we worried about didn’t happen until a bad guy finally tried it, such as Kerberos ticket manipulation.”]
Source: https://www.csoonline.com/article/2838986/what-makes-a-cyber-attack-go-big.html