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Central Command Inc. on Thursday released its so-called Dirty Dozen list of top twelve viruses for December, 2003. The report is based on virus incidents confirmed through the Medina, Ohio-based company’s Emergency Virus Response Team.

According to the company, the Gibe.C worm, with its HTML e-mail message that impersonated a Microsoft Web site, retained the top spot for December, a position that Klez.E held five times during the year.

Here is Central Command’s December Dirty Dozen ranking with the percentage of occurrences:

  1. Gibe.C—21.4 percent
  2. Klez.E—14.7 percent
  3. MiMail.I—12.8 percent
  4. MiMail.J—5.9 percent
  5. BugBear.B—5.2 percent
  6. MiMail.K—5.1 percent
  7. MiMail.A—3.7 percent
  8. Sober.C—1.9 percent
  9. Nachi—1.6 percent
  10. MiMail.C—1.6 percent
  11. Hawawi.G—1.2 percent
  12. Dumaru.A—1.1 percent
  13. Others—23.8 percent