Sophos ranks Klez G and H variants as number one on its top 10 virus chart for the month. Klez.h also made it onto other anti-virus vendor's top 10 lists, with industry pundits worried about its longevity.
Klez.h has accounted for more than 96 percent of all reports of virus attacks in the month of May, according to Moscow-based anti-virus company Kaspersky Labs. CIH and Elkern, two other viruses that have been found piggybacking on the Klez virus, have together made up another 1 percent.
Data on the Web site of UK-based mail service provider MessageLabs indicates that Klez has surpassed SirCam as the most prolific virus. The company has intercepted more than 767,000 copies of SirCam and has caught almost 908,000 copies of Klez.
Paul Ducklin, head of global support at Sophos Australia, said Klez's position in its rankings table is pretty much what it had expected. -There tends to be a trend in these things -- a small number of viruses will account for a large number of reports, but a virus doesn't need to be new to be a problem."
Ducklin points to Sircam, FunLove and Nimda as examples of viruses which still feature on its top 10 list, but aren't particularly new.
-I think people are doing the right thing," Ducklin said. -We're getting a lot of people now reporting viruses prevented correctly."
Although Sophos' top 10 are of viruses worldwide, Ducklin believed the trend was reflected in Australia. -It can happen that you get viruses which are regionalistic, but those tend to be viruses that depend on a particular language version [of a software]," he said.
Robert Lemos contributed to this report.
