Inside the Slammer Worm

Slammer (sometimes called Sapphire) was the fastest computer worm in history. As it began spreading throughout the Internet, the worm infected more than 90 percent of vulnerable hosts within 10 minutes, causing significant disruption to financial, transportation, and government institutions and precluding any human-based response. In this article, we describe how it achieved its rapid growth, dissect portions of the worm to study some of its flaws, and look at our defensive effectiveness against it and its successors.