Discovered: November 14, 2005
Updated: February 13, 2007 12:46:28 PM
Also Known As: CME-157, Win32.Sober.Q [Computer Associ, W32/Sober.t@MM [McAfee]
Type: Worm
Systems Affected: Windows


W32.Sober.V@mm is a mass-mailing worm that uses its own SMTP engine to spread. It sends itself as an email attachment to addresses gathered from the compromised computer. The email may be in either English or German.

Antivirus Protection Dates

  • Initial Rapid Release version November 15, 2005
  • Latest Rapid Release version August 08, 2016 revision 023
  • Initial Daily Certified version November 15, 2005
  • Latest Daily Certified version August 09, 2016 revision 001
  • Initial Weekly Certified release date November 16, 2005

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Elia Florio

Discovered: November 14, 2005
Updated: February 13, 2007 12:46:28 PM
Also Known As: CME-157, Win32.Sober.Q [Computer Associ, W32/Sober.t@MM [McAfee]
Type: Worm
Systems Affected: Windows


When W32.Sober.V@mm is executed, it performs the following actions:

  1. Arrives as a copy of the worm by mail and is a worm-dropper executable packed with UPX. Once executed it displays the following message box:

    "Packed Word Data not present"

  2. Creates and executes the following file which is the pure worm body:

    %Windir%\bbgdfvdd.exe

    Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.
  3. Creates the following files, also:

    • %Windir%\ConnectionStatus\Microsoft\services.exe
    • %Windir%\ConnectionStatus\Microsoft\concon.www
    • %System%\bbvmwxxf.hml - harmless
    • %System%\gdfjgthv.cvq - harmless
    • %System%\langeinf.lin - harmless
    • %System%\nonrunso.ber - harmless
    • %System%\rubezahl.rub - harmless
    • %System%\runstop.rst - harmless

      Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).

  4. Deletes the file %Windir%\bbgdfvdd.exe, at the end of the infection process.

  5. Tries to get access to the following file which if present on the system stops the infection process:

    %System%\filesms.fms

  6. May also delete the following file, if present:

    %System%\sacdata.dta

  7. Adds the value:

    " WinCheck" = "%Windir%\ConnectionStatus\Microsoft\services.exe"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    so that it runs every time Windows starts.

  8. Adds the value:

    "_WinCheck" = "%WinDir%\ConnectionStatus\Microsoft\services.exe"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

    so that it runs every time Windows starts.

  9. Tries to patch the TCPIP.SYS driver of Windows XP SP2 machine, in the following folders:

    • %System%\drivers\TCPIP.SYS
    • %System%\dllcache\TCPIP.SYS
    • %Windir%\ServicePackFiles\i386\TCPIP.SYS

      Note: The worm is able to patch different versions of the TCPIP.SYS file (build 2180,2505, 2631, 2685) by modifying the checksum of the file and changing the number of allowed half-open connections (a security fix introduced by Microsoft Security Bulleting MS05-019).This change alters the normal functioning of TCP/IP protocol and may cause Network problems.

  10. May try to end any of the following processes:

    • mrt.exe (Microsoft Windows Malicious Tool Removal)
    • asw*.tmp

  11. Locates the path under the following registry key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\LUALL.EXE\Path

  12. Tries to delete the following files inside this folder:

    • a*.exe
    • luc*.exe
    • ls*.exe
    • luu*.exe

  13. May display the following message box window, when the worm tries to connect to Internet:

    Title:
    LiveUpdate {Symantec}

    Text:
    Thank you for using LiveUpdate. All of the Symantec
    products and components are currently up-to-date.
    No Connection!

  14. Gathers email addresses from files with the following extensions:

    • .pmr
    • .phtm
    • .stm
    • .slk
    • .inbox
    • .imb
    • .csv
    • .bak
    • .imh
    • .xhtml
    • .imm
    • .imh
    • .cms
    • .nws
    • .vcf
    • .ctl
    • .dhtm
    • .cgi
    • .pp
    • .ppt
    • .msg
    • .jsp
    • .oft
    • .vbs
    • .uin
    • .ldb
    • .abc
    • .pst
    • .cfg
    • .mdw
    • .mbx
    • .mdx
    • .mda
    • .adp
    • .nab
    • .fdb
    • .vap
    • .dsp
    • .ade
    • .sln
    • .dsw
    • .mde
    • .frm
    • .bas
    • .adr
    • .cls
    • .ini
    • .ldif
    • .log
    • .mdb
    • .xml
    • .wsh
    • .tbb
    • .abx
    • .abd
    • .adb
    • .pl
    • .rtf
    • .mmf
    • .doc
    • .ods
    • .nch
    • .xls
    • .nsf
    • .txt
    • .wab
    • .eml
    • .hlp
    • .mht
    • .nfo
    • .php
    • .asp
    • .shtml
    • .dbx

  15. Saves the collected email addresses in the following file:

    %CurrentFolder%\concon.www

    Note: %CurrentFolder% is a variable that refers to the folder where the risk was originally executed.

  16. Sends email to the email addresses gathered. The email has an attachment of a .zip file that contains a copy of the worm. The email is written in English or German.

    ENGLISH EMAIL:

    Subject: Registration Confirmation

    Message Body:

    Thanks for your registration.
    Your data are saved in the zipped Word.doc file!

    Attachment: registration.zip

    Note: The zip file contains the file: Word-Text_packedList.exe.

    GERMAN EMAIL:

    Subject: Haben Sie diese EMail verschickt?  

    Message Body:

    Um es vorweg zu sagen: Ich bin kurz davor eine Anzeige gegen sie zu erstatten!
    Sie spinnen ja wohl! Die E-Mmailhat meine Tochter gelesen!!!!!!
    Ich habe Ihnen diese Word-Text Datei zu meiner Entlastung zurueckgeschickt.
    Es waere von Vorteil, wenn Sie sich dazu aeussern wuerden!!

    Attachment: Word-Text.zip

    Note: The zip file contains the file: Word-Text_packedList.exe.

  17. Sends emails in German to addresses that contain any of the following strings in the domain:

    • gmx.
    • .de
    • .li
    • .ch
    • .at
    • it


Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.

Writeup By: Elia Florio

Discovered: November 14, 2005
Updated: February 13, 2007 12:46:28 PM
Also Known As: CME-157, Win32.Sober.Q [Computer Associ, W32/Sober.t@MM [McAfee]
Type: Worm
Systems Affected: Windows


Removal using the W32.Sober Removal Tool
Symantec Security Response has developed a removal tool to clean the infections of W32.Sober.V@mm. Use this removal tool first, as it is the easiest way to remove this threat.

Manual Removal:


The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Disable System Restore (Windows Me/XP).
  2. Reinstall your Symantec antivirus program.
  3. Update the virus definitions.
  4. Run a full system scan and delete all the files detected.
  5. Delete any values added to the registry.
For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
Note:
When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).


2. To reinstall your Symantec antivirus program
As this risk attempts to remove the files and registry subkeys that your Symantec antivirus program uses, you may need to reinstall the program. If your Symantec antivirus program is not working properly, uninstall, and then reinstall it.


3. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to Virus Definitions (LiveUpdate).
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to Virus Definitions (Intelligent Updater).

    The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.


4. To scan for and delete the infected files
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected, click Delete.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode . Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.


5. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

    Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.

  4. Navigate to the subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

  5. In the right pane, delete the value:

    " WinCheck" = "%Windir%\ConnectionStatus\Microsoft\services.exe"

  6. Navigate to the subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

  7. In the right pane, delete the value:

    "_WinCheck" = "%WinDir%\ConnectionStatus\Microsoft\services.exe"

  8. Exit the Registry Editor.


Writeup By: Elia Florio