Virus top 10: Klez still wreaking havoc

Klez is still top of the virus top 10 - a position it has now held for more than six months.

The H variant of the stubborn worm accounted for 17 per cent of virus reports during August, according to anti-virus firm Sophos.

Second in the list was Yaha which moved up one place from number three. Badtrans is also still hanging around like an unwanted house guest - a non-mover at number four, having been in the top 10 all summer.

Klez-H spreads as an email attachment and uses a variety of subject lines. In terms of payload, the Klez-H variant is capable of carrying other viruses such as Elkern, which it then automatically launches once the attachment is executed.

As a result of this piggy-backing Elkern itself appears in fifth place in the August monthly chart.

Other viruses still with top 10 status after months in the wild include Magistr (8), Sircam (re-entry at 9) and Nimda (re-entry at 10).

The full top 10:
Numbers in brackets denote percentage of reported infections.

1. W32/Klez-H (17 per cent)
2. W32/Yaha-E (6.4 per cent)
3. JS/NoClose (6.4 per cent)
4. W32/Badtrans-B (5.3 per cent)
5. W32/Elkern-C (5.1 per cent)
6. W32/Higuy-A (2.7 per cent)
7. W32/Datom-A (2.4 per cent)
8. W32/Magistr-B (2.1 per cent)
9. W32/Sircam-A (1.9 per cent)
10. W32/Nimda-D (1.6 per cent)