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Aliases :

Sober, Email-Worm:W32/Sober


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 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.

Technical Details

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:

  • [HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run] or
  • [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]

to point to where the executable copies of the worm are dropped.

Some of the possible locations are:

  • %SysDir%\similare.exe
  • %SysDir%\sysrunll.exe

Propagation (email)

Sober will spoof different mail clients, using the headers:

  • X-Mailer: Microsoft Outlook Express 6.00.2600.0000
  • X-Mailer: Microsoft Outlook Express 5.00.3018.1300
  • X-Mailer: Safety_Mail Server
  • X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0)
  • X-Mailer: Microsoft Outlook IMO, Build 9.0.

It will send emails with the following subjects:

In German:

  • Neuer Virus im Umlauf!
  • Back At The Funny Farm
  • Sie versenden Spam Mails (Virus?)
  • Ein Wurm ist auf Ihrem Computer!
  • Langsam reicht es mir
  • Sie haben mir einen Wurm geschickt!
  • Hi Schnuckel was machst du so ?
  • VORSICHT!!! Neuer Mail Wurm
  • Re: Kontakt
  • RE: Sex
  • Sorry, Ich habe Ihre Mail bekommen
  • Hi Olle, lange niks mehr geh
  • Re: lol
  • Viurs blockiert jeden PC (Vorsicht!)
  • berraschung
  • Ich habe Ihre email bekommen !
  • Jetzt rate mal, wer ich bin !?
  • Neue Sobig Variante (Lesen!!)
  • Ich Liebe Dich

In English:

  • Congratulations!! Your Sobig Worms are very good!!!
  • You are a very good programmer!
  • Yours faithfully
  • Odin alias Anon
  • Odin_Worm.exe
  • New internet virus!
  • You send spam mails (Worm?)
  • A worm is on your computer!
  • You have sent me a virus!
  • Hi darling, what are you doing now?
  • Be careful! New mail worm
  • Re: Contact
  • Sorry, I've become your mail
  • Hey man, long not see you
  • Viurs blocked every PC (Take care!)
  • Surprise
  • I've become your mail!
  • Advise who I am!
  • New Sobig-Worm variation (please read)
  • I love you (I'm not a virus!)
  • I permanently get Spam-Mails from you and inside is a virus!!
  • You should remove these thing.

Attachment names are picked from the list:

  • AntiVirusDoc.pif
  • Check-Patch.bat
  • Screen_Doku.scr
  • Removal-Tool.exe
  • Perversionen.scr
  • Bild.scr
  • schnitzel.exe
  • robot_mail.scr
  • Privat.exe
  • AntiTrojan.exe
  • Mausi.scr
  • Anti-Sob.bat
  • security.pif
  • Funny.scr
  • Odin_Worm.exe
  • check-patch.bat
  • anti_virusdoc.pif
  • perversion.scr
  • removal-tool.exe
  • screen_doc.scr
  • potency.pif
  • pic.scr
  • playme.exe
  • robot_mailer.pif
  • private.exe
  • anti-trojan.exe
  • anti-Sob.bat
  • NAV.pif
  • funny.scr
  • little-scr.scr


Sober is an email worm, sending messages in English and German, sometimes posing as a fix from an Anti-Virus company.