Email-Worm:W32/Sober disguises itself as a security warning for a possible new worm and a fix coming from an Anti-Virus company. The worm uses attachment names such as anti_virusdoc.pif, check-patch.bat, playme.exe.
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note You need administrative rights to change the settings.
The worm was packed with a modified version of UPX and was written in Visual Basic. It has its own SMTP engine which will be used when sending email messages.
It will modify the Windows' registry under:
to point to where the executable copies of the worm are dropped.
Some of the possible locations are:
Sober will spoof different mail clients, using the headers:
It will send emails with the following subjects:
Attachment names are picked from the list:
Sober is an email worm, sending messages in English and German, sometimes posing as a fix from an Anti-Virus company.