Summary

The Sober.Z worm was found on November 15th, 2005. This Sober variant is similar to Sober.T, that appeared on November 14th:

http://www.f-secure.com/v-descs/sober_t.shtml

Like the previous variants, this one sends itself inside a ZIP archive as an attachment in e-mail messages with English or German texts. We also received several different droppers for this worm variant. They were apparently created by the worm author manually. They are all detected as 'Sober.z'.

Additional Details

This Sober variant sends a bit different e-mail messages:

Subject:

 Betr: Passwort & Account Daten

Body:

 Ihre Account bzw. Passwort aenderung wurde nun vorgenommen.
 Ihre neuen Zugangsdaten befinden sich Ge-Packt & Gesichert im Anhang!

 AutoMailSystem: #HF011BACC091F

Attachment name starts with:

 auto-mail_Daten

---- OR ----

Subject:

 Password Confirmation

Body:

 Your password has been changed successfully!
 Your new password is packed and safe in the attachment

 Auto-MailSystem: #B20F3A7299A1000FC2

Attachment:

 packed-password_text.zip

Detection

Sober.Z worm is detected with the following F-Secure Anti-Virus updates:

Version=2005-11-15_05

Writeup: Alexey Podrezov; November 16th, 2005;