W32.HLLW.Sinala@mm

SUMMARY

W32.HLLW.Sinala@mm is a worm that spreads by mass mailing and peer-to-peer file sharing. It modifies the registry keys and may not allow access to the system registry itself.

Protection

• Virus Definitions (LiveUpdate™ Weekly) November 17, 2003
• Virus Definitions (Intelligent Updater) November 13, 2003

Threat Assessment

Wild

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

Damage

• Damage Level: Medium
• Large Scale E-mailing: Sends via Outlook and P2P file sharing.
• Modifies Files: Modifies the system registry.

Distribution

• Distribution Level: Low
• Subject of Email: Contains one of the following words: axebahia hectlavo trancebaile teckno
• Name of Attachment: freesoft.avi.scr
• Size of Attachment: 22,528 bytes
• Target of Infection: KaZaA ICQ Outlook Grokster Morpheus Edonkey

TECHNICAL DETAILS

W32.HLLW.Sinala@mm is written in Visual Basic and is packed.

When this worm runs, it performs the following actions:

1. Sets itself to run as a process.
   
   
2. Copies itself to the following locations:
   • a:axebah.exe
   • a:BadboysII.scr
   • a:piratas.scr
   • a:ing.exe
   • %System%Cleanmgr.mcg
   • %System%freesoft.avi.scr
   • %System%kerneldll32.api
   • %System%mope.scr
   • %Windir%Cleanmgr.mcg
   • %Windir%molani.scr
     
     

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     Notes:
     
     -- %System% is a variable. The worm locates the System folder and copies itself to that location. By default, this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
     
     -- %Windir% is a variable. The worm locates the Windows installation folder (by default, this is C:Windows or C:Winnt) and copies itself to that location.

     ---

     
     
3. Creates HTML files that contain a MIME-encoded version of the executable. They drop a copy of the executable as %Windir%downloaded program filesAlanis.exe. This folder and the files in it have their attributes set as System, Read Only, and Hidden.
   
   Symantec antivirus products already detect the HTML files as Trojan.Sefex. The file names are:
   • C:mis documentosalanis.html
   • C:mis documentosavril.html
   • C:mis documentosevan.html
   • C:mis documentos emo.html
   • C:mis documentospamelaXXX.html
   • C:alanis.html
   • C:avril.html
   • C:evan.html
   • C: emo.html
   • C:pamelaXXX.html
     
     
4. Creates the file, C: azmania.txt, which may contain the string "demionklaz@hotmail.com."
   
   
5. Adds the value:
   
   "w32alanis" = "mope.scr"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
   
   so that the worm runs when you start Windows.
   
   
6. Disables access to the system registry by adding the key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersion
   PoliciesSystemDisableRegistryTools
   
   with a Dword value of 0x00000001.
   
   
7. Creates the registry keys:
   
   HKEY_CLASSES_ROOT.mcg
   
   HKEY_CLASSES_ROOTmcgfile
   
   These keys allow the execution with files that have .mcg extensions and that the worm dropped.
   
   
8. Adds itself to System.ini by modifying the shell= line in the [boot] section as follows:
   
   shell=%windir%Cleanmgr.mcg
   
   so that the worm runs when you start Windows 95/98/Me.
   
   
9. Attempts to mail itself to all the contacts in the Microsoft Outlook Address Book, using the format:
   
   Subject. The title of the message contains one of the following words:
   axebahia
   hectlavo
   trancebaile
   teckno
   
   Message:
   hay te envio el video que me pediste ta buenazo este es el video verdad espero que sea de tu agrado espero que te guste a mi me gsuto :pel grupo esta buenazo muy buen video Baile paso a paso aprendera a bailar rapido Nuevos pasos viva la musica espero que te guste los nuevos pasos
   
   Attachment: %sysdir%freesoft.avi.scr
   
   
10. Locates the following file-sharing program folders:
    
    C:ARCHIV~1GroksterMy Grokster
    C:Program FilesWinMXMy Shared Folder
    C:archiv~1WinMXMy Shared Folder
    C:Program FilesKaZaAMy Shared Folder
    C:ARCHIV~1KaZaAMy Shared Folder
    C:Program FilesGroksterMy Grokster
    C:Program FilesMorpheusMy Shared Folder
    C:archiv~1MorpheusMy Shared Folder
    C:Program FilesICQshared files
    C:archiv~1ICQshared files
    C:Program FilesEdonkey2000incoming
    C:archiv~1Edonkey2000incoming
    C:Program FilesKaZaA LiteMy Shared Folder
    C:archiv~1KaZaA LiteMy Shared Folder
    
    If the folder exists, the worm will copy itself as one or more of the following file names:
    
    alanis morri.mcg
    avril lavig.mcg
    picsXXX.mcg
    termi.mcg
    destino2.mcg
    seaevil.mcg
    prin.mcg
    paMXX.mcg
    evange.mcg
    saint.mcg
    ova4.mcg
    ova13.mcg
    ponw.mcg
    metalica.mcg

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

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. Update the virus definitions.
3. Run a full system scan and delete all the files detected as W32.HLLW.Sinala@mm.
4. Delete the value that was added to the registry.
5. Repair the System.ini file.
   

For specific details on each of these steps, 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 are satisfied that the threat has been removed, re-enable 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. 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.Sinala@mm, click Delete.

4. Deleting the values and keys 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.

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This is a two-step process. Before repairing the registry, you must first re-enable the registry tools.

Part 1

1. Click Start, then Run. (The Run dialog box appears.)
   
   
2. Type:
   
   notepad
   
   and then click OK. (Notepad opens a text file.)
   
   
3. Type, or copy and paste, the following text into the text file:
   
   REGEDIT4
   [HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionPoliciesSystem]
   "DisableRegistryTools"=dword:00000000
   
   [HKEY_CURRENT_USERSoftwareMicrosoftWindowsNTCurrentVersionPoliciesSystem]
   "DisableRegistryTools"=dword:00000000
   
   
4. Save the file as:
   
   repair.reg
   
   in the root folder (usually C:)
   
   
5. Click Start, and then click Run.
   
   
6. Type:
   
   regedit -s epair.reg
   
   and then click OK. This allows you to edit the registry.

Part 2

1. Click Start, and then click Run. (The Run dialog box appears.)
   
2. Type regedit
   
   Then click OK. (The Registry Editor opens.)
   
   
3. Navigate to the key:
   
   HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
   
   
4. In the right pane, delete the value:
   
   "w32alanis" = "mope.scr"
   
   
5. Navigate to and delete the key:
   
   HKEY_CLASSES_ROOT.mcg
   
   
6. Navigate to and delete the key:
   
   HKEY_CLASSES_ROOTmcgfile
   
   
7. Exit the Registry Editor.
   
   

5. Repairing the System.in 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. Windows will regenerate the System.ini file.
        
        
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, make the appropriate path substitution.
   
   
4. In the [boot] section of the file, look for a line similar to:
   
   shell = Explorer.exe C:WINDOWSCleanmgr.mcg
   
   
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. Click File, and then click Save.
7. Click File, and then click Exit.