2000
May : The VBS/Loveletter (‘ILOVEYOU’) worm appeard. As of 2004 this is the most costly virus to business, causing upwards of 10 billion dollars in damage.
2001
January : A worm strikingly similar to the Morris worm, names the Ramen worm infected only Red Hat Linux machines running version 6.2 and 7.
July 13 : The Code Red worm attacking Microsoft Internet Information Services.
October 26 : The Klez worm is first identified.
2003
January 24 : The SQL slammer worm also known as the Sapphire worm, attacked vulnerabilities in Microsoft SQL Server and causes widespread problems on the internet.
August 12 : The Blaster worm, also known as the Lovesan worm, spread rapidly by exploiting Microsoft Windows computers.
2004
January : MyDoom emerges, and currently holds the record for the fastest-spreading mass mailer worm.
December : Santy, the first known “webworm” is launched. It infected around 40000 sites before Google filtered the search query by the worm.
2005
August 16 : The Zotob worm and several variations of malware exploiting the vulnerability described in MS05-039 are discovered. The effect was overblown because several United States media outlets were infected.
2006
January 20 : The Nyxem work discovered. It spread by mass-mailing. It attempts to certain types, such as Microsoft Office files.
February 16 : Discovery of the first-ever virus for Mac OS X, a low-threat worm known as OSX/Leap-A or OSX/Oompa-A, is announced.
2007
January 7 : A worm generated by hackers of the popular website MySpace was discovered by many users on the site.