The Sober worm is now infecting one in every 22 emails as its rise continues. Propagating itself on the back of emails pretending to be football World Cup tickets the Sober-N variant has now infiltrated over 40 countries.
On Monday SC reported the worm was spreading quickly, but today reports are suggesting it shows no signs of slowing down.
"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 at antivirus company Sophos. "No-one should be fooled into thinking that email viruses are a thing of the past."
According to Sophos, Sober accounts for nearly 80 percent of all viruses currently circulating the internet.
"In particular, this worm appears to have caused problems by posing as an offer of free tickets for the soccer World Cup tournament in Germany next year," said Cluley. "Many people found the prospect of free tickets to the prestigious sporting event just too hard to resist."
The news arrives on the same day that the first social engineering worm to arrive in emails celebrates its fifth anniversary.
"LoveLetter was one of the first, and most notable, examples of social engineering," said David Emm, senior technology consultant at antivirus company Kaspersky. "It arrived as an attachment to an innocent looking email containing the subject line 'I LOVE YOU' and the body text 'Kindly check the attached LOVELETTER coming from me'."
Unaware that malicious code could be hidden inside an attachment thousands fell for the social engineering technique. In the guise of the World Cup tickets scam it still appears to be working today. As Emm said in Kaspersky's weblog, "Who wouldn't want World Cup tickets."