SophosLabs’ Global Network of Virus and Spam Analysis Centers recently found Sober-N worm to be on a continuous move ever since it first appeared on Monday.

According to Sophos’ lab report, the worm has already spread to over 40 countries and is rapidly pacing, globally. Sophos said Sober-N accounts for 79.29 percent of viruses that are currently being monitored by Sophos throughout various countries and networks. It also says that Sober now accounts for nearly 4.5 percent in all e-mail viruses.

"One in every 22 emails sent across the Internet is currently infected by the Sober-N worm -- making this one of the biggest virus outbreaks of the year," said Graham Cluley, Senior Technology Consultant, Sophos.

Sophos said Sober is spreading via e-mails with attractive subject headings to get unsuspecting users to execute the worm. One of the most famous subject heading it’s targeting is related to the latest Soccer World Cup tournament. The worm is offering users free World Cup tickets, which is getting many people to click on the attachment.

As always, Sophos recommends that users do not open any attachment regardless of the tempting offers, and update their anti-virus software.