As many as one in eight of all e-mails are now infected with the Sober worm, security experts have warned.
Security firm MX Logic said that as of noon on Tuesday, its threat centre had blocked more than a million e-mail messages infected with the latest variant of the prolific Sober worm, Sober-Z – one in every eight e-mails. MX Logic first detected Sober-Z on Monday.
Meanwhile SophosLabs said the worm was spreading at such a rate that it accounted for more than 81% of all reported viruses, making it the world’s most widespread computer virus.
The worm, which sends itself as an e-mail attachment and attempts to turn off security software on the user's computer, now infects one in every 17 e-mails.
The e-mails may come from fake FBI or CIA agents or contain offers of celebrity video clips featuring Paris Hilton and Nicole Richie. But each zip file attachment contains a copy of the worm with the filename "File-packed_dataInfo.exe". The worm scans hard drives for e-mail addresses, in order to propagate itself.
SophosLabs have distributed a typical infected e-mail, with the subject line “hi, ive a new mail address”, and the text: “hey its me, my old address dont work at time. i dont know why?! in the last days ive got some mails. i' think thaz your mails but im not sure!” It then invites the recipient to “read and check” the attached file, mailtext.zip.