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Virus Top 10: A Sobering prospect
A month of Mimail broken up only by a new entry and the old hands...

By Will Sturgeon

Published: Friday 28 November 2003

Mimail is dominating the virus landscape at the moment, accounting for five of the top 10 most virulent viruses of the past month.

Mimail variants C, F, A, J and E all featured in the list compiled by Sophos, and accounted for a quarter of all reports, but top spot went to new entry Sober, which accounted for a massive 32.6 per cent of all reported incidences of malware.

Graham Cluley, senior technology consultant at Sophos, said it is Sober's ability to change subject line which makes it difficult to identify "with the naked eye".

The virus can even change subject line according to the country it believes it is in - Cluley said it will appear with a German subject line if it 'thinks' it is being opened on a German machine.

Other places in the chart, designed to publicise the greatest threats at large, were taken by familiar names such as Gibe, Klez and Nachi which have been doing the rounds for quite some time.

Klez has now been an ever-present in this chart for 22 months now - though it's stock is at last showing signs of decline - accounting for just 2.2 per cent of virus reports, and occupying ninth place. However, its record is one which is unlikely to be broken for a very long time.

The full top 10 looks like this:

1. W32/Sober-A (Sober worm) 32.6 per cent NEW ENTRY
2= W32/Mimail-C (Mimail variant) 9.5 per cent
2= W32/Mimail-F (Mimail variant) 9.5 per cent
4. W32/Dumaru-A (Dumaru virus) 8.0 per cent
5. W32/Mimail-A (Mimail worm) 5.1 per cent
6. W32/Gibe-F (Gibe variant) 4.5 per cent
7. W32/Nachi-A (Nachi worm) 2.6 per cent
8. W32/Mimail-J (Mimail variant) 2.4 per cent
9. W32/Klez-H (Klez variant) 2.2 per cent
10. W32/Mimail-E (Mimail variant) 1.5 per cent
Others 22.1 per cent