SQL Slammer made the rounds in 2003. The worm reportedly infected every system vulnerable to the attack within a mere 15 minutes, according to Symantec's Haley. It caused a denial of service on some Internet hosts and dramatically slowed down general Internet traffic, spreading rapidly and infecting most of its 75,000 victims within ten minutes.
"No one had ever seen malware spread at those speeds before," says Haley.
The worm was based on proof-of-concept code demonstrated at the Black Hat Briefings by David Litchfield.