The yearly reported number for 2009 was 16,392: significantly decreased from 21,591 in 2008 and got back to almost of the same level of 17,425, the yearly reported number for 2003.  This reported number is gradually decreasing year by year since such virus which massively distributes virus mail to enlarge/cause severe infection has not been existed in the past several years.

Chart 1-1: Reported Number of Virus /Year

Number of viruses reported was 125 (2008: 136): of 9 viruses were initially reported to IPA in 2009 (2008: 19).

Of the viruses reported, W32/Netsky was most frequently detected; then, W32/Downad and W32/Mydoom followed.  Since 2004, W32/Netsky was most frequently reported every year and its detection number is taking over a large proportion against the entire detection number.

For your information, W32/Downad is the virus which exploits security hole (s) (i.e., vulnerability) and the detection number for its variants which enlarge infection via USB memory was significantly increased in April 2009 (See the Chart 2-1).

Chart 2-1: Detection Number by Virus

According to the reported number by virus, though the reported number for W32/Netsky is gradually decreasing, it is still reported the most.  Most of the reported number for the viruses other than W32/Netsky was turned to be decreasing; however, W32/Mydoom was increased and decreased over and over: in the event, their reported number in December 2009 was greater than the one in January 2009.

Chart 2-2: Reported Number by Virus

Information-Technology Promotion Agency, Security Center
Hanamura/Kagaya/Ooura
Tel:+81-3-5978-7527
Fax:+81-3-5978-7518
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