Netsky's return to the top comes despite protection against this family of worms having been available for more than three years. Interestingly, just 0.18 percent or one in 555 e-mails was infected in March, yet 8,835 new threats were detected. These numbers indicate that while malware spreading via e-mail is still causing trouble, the vectors used to distribute threats are changing: hackers are continuing their move away from mass-mailing worms in favor of using spam messages with links pointing to infected Web pages.
The top ten list of malware threats in March 2007 reads as follows:
"Unwanted e-mails hiding copies of Netsky are still spreading like weeds in an untended garden, showing how well seeded these mass-mailing threats are," said Carole Theriault, senior security consultant at Sophos. "It's frustrating to think that there are a bunch of new threats out there that are much more targeted and devious in their approach, yet how can we expect the average computer user to protect against them when the Netskys and Mytobs remain so rooted? Users need to roll up their sleeves and commit to keeping their PCs secure both for their sake and the sake of everyone else connected to the Web."
Sophos's global network of monitoring stations has also revealed that the UK has jumped into the top five countries hosting malware-infected Web pages.
"Since December 2006, we have seen some remarkable changes in the countries hosting the most malware," continued Theriault. "China has taken the lead from the United States, but more dramatically, the United Kingdom, which hosted less than 1 percent in December is now responsible for more than 5 percent. This significant increase should be a warning to those hosting Web sites in the UK to ensure that they have patched against vulnerabilities that might be lurking on their site."
