The return of the Sober worm has seen it rocket to the top of Sophos' chart of most prolific viruses in May.
IT managers, in their daily firefight against viruses, saw a massive spike in the instances of the Sober offshoot, as it displaced Zafi.D atop the "least wanted" list provided by the British antivirus company. The mass-mailing worm, which is carried by e-mails in both English and German, is known as Sober.N by Sophos, but has also been variously named Sober.P, Sober.O and Sober.S by other security providers.
"Sober.N stormed to the top of the chart in early May, making it one of the biggest outbreaks so far this year," Carole Theriault, a security consultant at Sophos, said in a statement on Wednesday. "This manipulative e-mail worm spread quickly, using social engineering tricks, such as offering free World Cup tickets, to entice recipients into opening the infected attachment."
In total, Sober-N accounted for 43.8 percent of all reported viruses, Sophos said. The e-mails typically purported to offer tickets for soccer's Fifa World Cup 2006, or had subject lines referring to passwords or a booking confirmation.
Recent arrival on the virus landscape Mytob (Z and AZ variants) also made its presence felt. SOURCE