W32.HLLW.Southghost

SUMMARY

W32.HLLW.Southghost a worm that spreads through email and file-sharing networks.

The email has the following characteristics:

Subject: Espero que te llege a tiempo...
Attachment: BuenasNuevas.doc.pif

The worm is written in Microsoft Visual Basic and packed with Petite.

Protection

• Virus Definitions (LiveUpdate™ Weekly) December 3, 2003
• Virus Definitions (Intelligent Updater) December 1, 2003

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low

Distribution

• Distribution Level: Low
• Subject of Email: Espero que te llege a tiempo...
• Name of Attachment: BuenasNuevas.doc.pif

TECHNICAL DETAILS

When W32.HLLW.Southghost is executed, it performs the following actions:

1. Creates following folders:
   
   • C:KaZaAMy Shared Folder
   • C:edonkey2000incoming
   • C:icqshared files
     
     
2. Deletes following files:
   
   • C:WindowsRegedit.exe
   • C:WindowsScanregw.exe
   • C:WindowsSystemMsconfig.exe
   • C:WindowsSystemSfc.exe
     
     
3. Copies itself as following:
   
   • %System%Regsrv32.com
   • %Windows%System.com
   • %Windows%Regedit.exe
   • %Windows%SystemMsconfig.exe
   • %Windows%SystemTexto 3D.scr
   • %Windows%SystemWindows volando.scr
   • %Windows%SystemObjetos 3D.scr
   • %Windows%SystemLaberinto 3D.scr
   • %Windows%SystemTuberas 3D.scr
   • %Windows%SystemFiguras en 3D.scr
   • %Windows%GHoST_Vrl.worm
   • %Windows%SystemCurvas y colores.scr
   • %Windows%SystemFormas y figuras.scr
   • %Windows%SystemMarquesina desplazndose.scr
   • %Windows%SystemMis imgenes.scr
   • %Windows%SystemPantalla neutra.scr
   • %Windows%SystemVolando por el espacio.scr
   • C:Mis documentosShakira.scr
   • C:WindowsEscritorioWebCamS.pif
   • C:WindowsSystemTexto 3D.scr
   • C:WindowsSystemWindows volando.scr
   • C:WindowsSystemObjetos 3D.scr
   • C:WindowsSystemLaberinto 3D.scr
   • C:WindowsSystemTuberas 3D.scr
   • C:WindowsSystemFiguras en 3D.scr
   • C:WindowsSystemCurvas y colores.scr
   • C:WindowsSystemFormas y figuras.scr
   • C:WindowsSystemMarquesina desplazndose.scr
   • C:WindowsSystemMis imgenes.scr
   • C:WindowsSystemPantalla neutra.scr
   • C:WindowsSystemVolando por el espacio.scrC:Autoexec.com
   • C:Mis documentosBruceLee.com
   • C:BuenasNuevas.doc.pif
   • C:Mis documentosNoLeer.bat
   • C:KaZaAMy Shared FolderHotmail Hack Crack 2003.exe
   • C:KaZaAMy Shared FolderListado de Msica 2003.com
   • C:KaZaAMy Shared FolderShakira and Britney Screen Saver.scr
   • C:KaZaAMy Shared FolderNorton and McAffe Antivirus 2003 KeyGen Crack.exe
   • C:edonkey2000incomingHotmail_mail_hack.exe
   • C:edonkey2000incomingNorton and McAffe Antivirus 2003 KeyGen Crack.exe.exe
   • C:edonkey2000incomingAge_of_Mythology_Crack.exe
   • C:edonkey2000incomingListado de Msica 2003.exe
   • C:icqshared filesNorton and McAffe Antivirus 2003 KeyGen Crack.exe
   • C:icqshared filesMusic 2003 List.exe
   • C:icqshared filesShakira and Britney Screen Saver 2003.scr
   • C:icqshared filesHotmail_hack_guide.exe
   • A:Horoscopo2003.exe
   • A:INSTALL.EXE
   • A:SETUP.EXE
   • A:INSTALAR.EXE
   • C:ARCHIVOS DE PROGRAMAPERAVPAV.EXE
   • C:ARCHIVOS DE PROGRAMAPERAVPER.EXE
   • C:ARCHIVOS DE PROGRMAPERAVINSTALAR.EXE
   • C:ARCHIVOS DE PROGRAMAPERAVPERUPD.EXE
   • C:ARCHIVOS DE PROGRAMAPERAVPAVMAIL.EXE
   • C:ARCHIVOS DE PROGRAMAPERAVTSKWIZAR.EXE
   • C:ARCHIVOS DE PROGRAMAPERAVDOWNLOAD.EXE
   • C:ARCHIVOS DE PROGRAMATHE HACKERTHAV.EXE
   • C:ARCHIVOS DE PROGRAMATHE HACKERTH32.EXE
   • C:ARCHIVOS DE PROGRAMATHE HACKERTH32UPD.EXE
   • C:ARCHIVOS DE PROGRAMATHE HACKERTHMAIL.EXE
   • C:ARCHIVOS DE PROGRAMATHE HACKERUNINST.EXE
   • D:GHoST.exe
   • D:WIN98SEINSTALL.EXE
   • D:WIN98SESETUP.EXE
   • D:WIN98SEINSTALAR.EXE
   • E:WIN98SEINSTALL.EXE
   • E:WIN98SESETUP.EXE
   • E:WIN98SEINSTALAR.EXE
   • F:WIN98SEINSTALL.EXE
   • F:WIN98SESETUP.EXE
   • F:WIN98SEINSTALAR.EXE
     
     
4. Adds the values:
   
   • <executed file name>="%System%Regsrv32.com"
   • "REGEDIT"="%System%Regsrv32.com"
     
     to the registry key:
     
     HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersion
     RunService
     
     so that the worm runs when you start Windows.
     
5. Modifies the shell= command in the C:WindowsSystem.ini file to:
   
   shell=explorer.exe system.com
   
   
6. Adds following line in the C:WindowsSystem.ini file:
   
   SCREENSAVE.EXE=C:WindowsSystemTexto 3D.scr
   
   
7. Sends email to Windows Messenger and MSN Messenger users.
   
   
8. The email has the following characteristics:
   
   From: lindaflorcita__22@hotmail.com
   Subject: Espero que te llege a tiempo...
   Message:
   Hola, no sabes cuantas buenas y malas noticias te tengo que
   dar, al ser tantas la escribo en un
   documento, que esta adjunto
   a este mail, espero que lo leas y me des animospara
   afrontar estos ultimos hechos...
   Attachment: BuenasNuevas.doc.pif

Recommendations

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

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

These 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. Update the virus definitions.
3. Restart the computer in Safe mode or VGA mode.
4. Run a full system scan and delete all the files detected as W32.HLLW.Southghost.
5. Restore the overwritten files.
6. Reverse the changes that the worm added to the registry.
7. Edit the changes to the System.ini file.
   

For specific details on each of these procedures, read the following instructions.

1. Disabling 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:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

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Note: When you are completely finished with the removal procedure, and you are satisfied that the threat has been removed, you should reenable System Restore by following the instructions in the aforementioned documents.

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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. Updating 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 the Virus Definitions (LiveUpdate).
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). 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 the Virus Definitions (Intelligent Updater).
  
  The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. Restarting the computer in Safe mode or VGA mode
Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode or VGA mode.

• For Windows 95, 98, Me, 2000, or XP users, restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
• For Windows NT 4 users, restart the computer in VGA mode.
  

4. Scanning for and deleting the infected files

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
   • For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan All Files."
2. Run a full system scan.
3. If any files are detected as infected with W32.HLLW.Southghost, click Delete.

5. Restoring deleted or overwritten files
Restore the following files overwritten by the worm from the backup, if necessary:

• C:WindowsRegedit.exe
• C:WindowsScanregw.exe
• C:WindowsSystemMsconfig.exe
• C:WindowsSystemSfc.exe
  

The following documents provide general instructions on how to extract files. This information is provided for your convenience. The exact steps may slightly vary depending on the configuration of your operation system, the location of the files, and so on. For additional information, read the Help files, contact Microsoft, or refer to the following Windows documentation:

• The Microsoft Knowledge Base article, "How to Extract Original Compressed Windows Files," Article ID Q129605, has detailed information for Windows 95/98/Me.
• "How to extract files in Windows 98 and Windows Me"
• "How to extract files using Windows 2000 or Windows NT 4.0"
• "How to restore system files in Windows XP"

6. Deleting the value from the registry

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WARNING: 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 keys only. Read the document, "How to make a backup of the Windows registry," for instructions.

---

1. Click Start, and then click Run. (The Run dialog box appears.)
2. Type regedit, and then click OK. (The Registry Editor opens.)
3. Navigate to the following key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRunService
   
4. In the right pane, delete the values:
   
   • <executed file name>="%System%Regsrv32.com"
   • "REGEDIT"="%System%Regsrv32.com"
     
5. Click Registry, and click Exit.

7. Editing the System.ini file
If you are running Windows 95/98/Me, follow these steps:

1. The function you perform depends on your operating system:
   • Windows 95/98: Go to step b.
   • Windows Me: If you are running Windows Me, the Windows Me file-protection process may have made a backup copy of the System.ini file that you need to edit. If this backup copy exists, it will be in the C:WindowsRecent folder. Symantec recommends that you delete this file before continuing with the steps in this section. To do this:
     1. Start Windows Explorer.
     2. Browse to and select the C:WindowsRecent folder.
     3. In the right pane, select the System.ini file and delete it. The System.ini file will be regenerated when you save your changes to it in step f.
        
        
2. Click Start, and then click Run.
3. Type the following, and then click OK.
   
   edit c:windowssystem.ini
   
   (The MS-DOS Editor opens.)
   
   NOTE: If Windows is installed in a different location, the worm did not modify system.ini, and you can skip this step.
   
   
4. In the [boot] section of the file, look for a line similar to:
   
   shell = Explorer.exe system.com
   
   
5. If this line exists, delete everything to the right of Explorer.exe.
   
   When you are done, it should look like:
   
   shell = Explorer.exe
   
6. In the [boot] section of the file, look for a line similar to:
   
   SCREENSAVE.EXE=C:WindowsSystemTexto 3D.scr
   
   
7. Delete the line.
   
   
8. Click File, and then click Save.
   
   
9. Click File, and then click Exit.