A variation of the MiMail worm is attacking systems around the world.

The worm, dubbed MyDoom, spreads via spam mail and runs on Windows 98, ME, NT, 2000 and XP. When executed, the worm launches denial of service (DoS) attack against the Web site www.sco.com.

According to Trend Micro's antivirus research, WORM_MIMAIL.R is rated 'high' for damage and distribution potential, and 'medium' for reported infections and overall risk.