Home > Threat descriptions >

Email-Worm:W32/Sober

Classification

Category: Malware

Type: Email-Worm

Aliases: Sober, Email-Worm:W32/Sober

Summary


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.

Removal


Automatic action

Based on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the detected program or file, or ask you for a desired action.

Knowledge Base

Find the latest advice in our Community Knowledge Base.

About the product

See the manual for your F-Secure product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

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.

Installation

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
  • CM-Recover.com
  • Bild.scr
  • schnitzel.exe
  • robot_mail.scr
  • RobotMailer.com
  • Privat.exe
  • AntiTrojan.exe
  • Mausi.scr
  • NackiDei.com
  • Anti-Sob.bat
  • security.pif
  • Funny.scr
  • Liebe.com
  • Odin_Worm.exe
  • check-patch.bat
  • anti_virusdoc.pif
  • perversion.scr
  • removal-tool.exe
  • screen_doc.scr
  • potency.pif
  • CM-Recover.com
  • pic.scr
  • playme.exe
  • robot_mailer.pif
  • private.exe
  • anti-trojan.exe
  • love.com
  • nacked.com
  • anti-Sob.bat
  • NAV.pif
  • funny.scr
  • little-scr.scr

Variant:Sober.A

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