W32.HLLP.Shodi.B

SUMMARY

W32.HLLP.Shodi.B is a virus that prepends itself to the files that have a .exe extension.

Protection

• Virus Definitions (LiveUpdate™ Weekly) April 21, 2004
• Virus Definitions (Intelligent Updater) April 21, 2004

Threat Assessment

Wild

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

Damage

• Damage Level: Medium
• Modifies Files: Infects .exe files.
• Compromises Security Settings: May drop a copy of "Remote Administrator" (Remacc.Radmin), allowing unauthorized remote access.

Distribution

• Distribution Level: Low
• Ports: Variants that drop the backdoor listen on TCP ports 6351 and 6352.

TECHNICAL DETAILS

When a file infected with W32.HLLP.Shodi.B is executed, the virus does the following:

1. Extracts the original host file to a file with a .ogr extension, and then executes it.
   
   For example, if Notepad.exe is infected, the virus will extract the original Notepad program to Notepad.ogr, and then will run it.
   
   
2. Attempts to install a backdoor to an infected system by creating the following files:
   
   • %System%oobb.exe: An installer detected as Backdoor.Trojan.
   • %System%Cheatle.exe: A VB application detected as Backdoor.Trojan.
   • %System%GigaByte.exe: A remote administration tool detected as Remacc.Radmin.
   • %System%AdmDll.dll: A .dll component of Remacc.Radmin.
   • %Windir%_server.exe: Another copy of GigaByte.exe.
   • %Windir%start.exe: Another copy of Cheatle.exe.
     
     

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     Notes:
   • Some variants of this virus create %System%oobb.exe as a zero-byte file. In this case, the other files will not be present.
   • %Windir% is a variable. The virus locates the Windows installation folder (by default, this is C:Windows or C:Winnt) and copies itself to that location.
   • %System% is a variable. The virus 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).

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     If these files are successfully dropped, they will add the following entries
     
     "Cheatle"="%System%GigaByte.exe /port:6351 /pass:hellomine"
     "GigaByte"="%System%Cheatle.exe"
     
     to the registry key:
     
     HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
     
     so that the backdoor runs when Windows starts.
     
     The backdoor is configured to listen on TCP ports 6351 and 6352.
     
     
3. Searches for the files that have the .exe extensions on all the hard drives, starting with drive C. The worm searches all the folders on the hard drive, except those with the following names:
   
   • Windows
   • System
   • System32
     
     It does not infect the files that have the following names:
     
   • IEXPLORE.EXE
   • ccApp.exe
   • ccRegVfy.exe
     
     
4. Prepends itself to some of the files that it finds.
   
   The virus infects Portable Executable (PE) files that have a resource directory. Such files often contain a custom icon in the .rsrc section of the file. This icon is displayed instead of the default Windows icon.
   
   When the virus infects such a file, it modifies its own icon to resemble the icon of the host file.
   
   
5. Makes a temporary copy of itself as %System%ShohdiWithPrograms.ams.
   
   
6. If the worm is executed on May 5, 2005, the virus will display a message box containing the text:
   
   Important !!!
   Please read this
   The Next is in Arabic
   
   followed by Arabic text.

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. Re-install your Symantec antivirus program.
3. Update the virus definitions.
4. Run a full system scan and repair all the files detected as W32.HLLP.Shodi.B.
5. Delete the values that were 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:

• "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. To reinstall your Symantec antivirus program
As this virus attempts to remove the files and registry keys that your Symantec antivirus program uses, you may need to re-install the program. If your Symantec antivirus program is not properly working, uninstall, and then re-install 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 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.

4. To scan for and repair the infected files

1. Start your Symantec antivirus software and make sure that it is configured to scan all 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.HLLP.Shodi.B, click Repair.
4. If any files are detected as Backdoor.Trojan or Remacc.Radmin, click Delete.

5. To delete the values 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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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 these values if they are present:
   
   "Cheatle"="%System%GigaByte.exe /port:6351 /pass:hellomine"
   "GigaByte"="%System%Cheatle.exe"
   
   
5. Exit the Registry Editor.