New Sober variant tricking users

IDG News Service - A new Sober mass-mailer worm is slithering its way around the Internet and tricking users into opening attachments with clever messages in both English and German, antivirus companies warned.
W32.Sober.N@mm sends e-mail messages with the subject headers "I've_got your EMail on my_account!" and "FwD: Ich bin's nochmal" and carries attachments with names like your_text.zip, according to Helsinki security firm F-Secure Corp. When opened, the attachment scans files on the infected computer to harvest e-mail addresses that enable the worm to spread.
Symantec Corp. also released an advisory on the Sober variant, rating its damage as "medium."
The worm was first reported at 2 a.m. CET, and has been spreading in Europe, particularly in German speaking countries, according to Mikko Hypponen, director of antivirus research at F-Secure.
The body text for the English version begins "Hello, First, Very Sorry for my bad English. Someone is sending your private e-mails on my address." It then tells the recipient that 10 of their personal e-mails are attached in a zip file.
The message represents a clever bit of social engineering because it appears plausible, and in the case of the German versions, is in a local language, Hypponen said. Most users are accustomed to receiving spam and viruses in English, he added.
The motive behind creating the worm is still unclear and F-Secure does not know the identity of the author, Hypponen said.
It's difficult to tell how rapidly the worm is spreading because the author used computers infected with a previous version of Sober to launch the new variant and "get a head start," Hypponen said.
The researcher said the author is based in Europe because Sober variants are always released early in the morning European time, giving them a chance to spread before the antivirus companies start their day.
F-Secure and Symantec both advised Internet users to update their antivirus software to guard against the new worm.