W32.Sober@mm

15 November 2008 Worm 0 Comment

W32.Sober@mm is a mass-mailing worm that utilizes victim’s computer as SMTP engine to email a copy of itself. This infection is a memory-resident worm that specifically targets Windows platform. W32.Sober@mm is written in Microsoft Visual Basic programming language and is UPX compacted.

Other Alias: W32/Sober@MM, I-Worm.Sober , W32/Sober-A, WORM_SOBER.A , Win32.Sober.A, Win32.HLLM.Odin,  Worm/Sober,  Win32/Sober.A@mm,  I-Worm.Win32.Sober,  I-Worm/Sober.A,  W32/Sober.A.worm

Damage Level: Low

Systems Affected: Windows 9x, 2000, XP, Windows Vista

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Characteristics
Upon execution, this worm will drop three versions of the file under Windows system directory. The mail file is SIMILARE.EXE. The two other files are consisting of any variations listed on “Associated Files and Folder” area. To run these varying files, the worm will create a registry entries that calls for execution each time Windows starts.

While inside the infected computer, W32.Sober@mm gathers email address and saves the collected information under MEDIA.DLL file.

Distribution
The worm will spread via using a built-in Send Mail Transfer Protocol (SMTP). It collects contact details or email address from the infected computer where it later will be the recipients of spam email messages containing a copy of the worm.

An email sent out by this worm contains variations of subject and attached file. It fakes the FROM field and pretends to be coming from a legitimate and trusted sender. Some examples of the messages are as follows:

Email Message:
I permanently get Spam-Mails from you and inside is a virus!!
You should remove these things.
Sorry, but the ODIN Worm is probably on your computer!
You should check this with the patch application.
See you soon
Attachment: check-patch.bat

Email Message:
Programmer of the -Sobig Worm-
Congratulations!! Your Sobig Worms are very good!!!
You are a very good programmer!
Yours faithfully
Odin alias Anon
pan>Attachment: Odin_Worm.exe

Added Registry Entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run "(any of the given files)" ex: "antiv.exe"
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run "(any of the given files)" ex: "antiv.exe"

Associated Files and Folders:

%System%/antiv.exe 
%System%/driver.exe 
%System%/driverini.exe 
%System%/drv.exe 
%System%/expoler.exe 
%System%/filexe.exe 
%System%/hlp16.exe 
%System%/lssas.exe 
%System%/qname.exe 
%System%/spoole.exe 
%System%/swchost.exe 
%System%/syshost.exe 
%System%/systemchk.exe 
%System%/systemini.exe 
%System%/winchk.exe 
%System%/winlog32.exe 
%System%/winreg.exe

1. Temporarily Disable System Restore (Windows Me/XP). [how to]
2. To be able to identify even the most recent variant of W32.Sober@mm, open your antivirus application and update the virus definition file.

3. Start Windows in Safe Mode with Networking.
- From a power-off state, turn on the computer and press F8 on your keyboard repeatedly.
- Your computer will display Windows Advanced Boot Options menu. Please select Safe Mode with Networking.
- The system will now boot Windows and loads only necessary drivers and files.

4. Connect to Internet and download W32.Sober Removal Tool from Symantec.

5. Once the download completes, double click on the file FixSbr.exe to run the program.

6. Allow the tool to run until it finds and delete the virus.