W32.HLLW.Warpigs.C

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Discovered: December 19, 2003
Updated: February 13, 2007 12:15:22 PM
Also Known As: Backdoor.Spyboter.gen [KAV]
Type: Worm
Systems Affected: Windows


W32.HLLW.Warpigs.C is a variant of W32.HLLW.Warpigs worm that contains backdoor Trojan functionality. It attempts to copy itself to computers that have weak administrator passwords.

The backdoor functionality is accomplished by connecting to a specific mIRC server and joining a specific channel to receive instructions. The default ports are 6666 and 6667.

Antivirus Protection Dates

  • Initial Rapid Release version December 20, 2003
  • Latest Rapid Release version March 03, 2008 revision 035
  • Initial Daily Certified version December 20, 2003
  • Latest Daily Certified version March 03, 2008 revision 037
  • Initial Weekly Certified release date December 23, 2003

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

Writeup By: Kevin Ha

Discovered: December 19, 2003
Updated: February 13, 2007 12:15:22 PM
Also Known As: Backdoor.Spyboter.gen [KAV]
Type: Worm
Systems Affected: Windows


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

  1. Copies itself as %System%\tskmg.exe.


    Note: %System% is a variable. The worm locates the System folder and copies itself to that location. By default, this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).

  2. Creates the file, %System%\pgonwe.exe, which is a copy of the SysInternals psexec utility. The worm uses this file to attempt to copy and run itself on computers that have weak administrator passwords.

  3. Attempts to connect to computers that have weak administrator passwords. Some of the passwords it attempts to use are:

    <null>
    000
    administrateur
    test123
    abc123
    passwd
    pass
    edu
    Owner
    PASSWORD
    ADMIN
    root
    ROOT
    GUEST
    administrator
    Administrator
    ADMINISTRATOR

  4. Adds the value:

    "winsockdriver"="tskmg.exe"

    to the registry keys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce

    so that the worm runs when you start Windows.

  5. Adds the value:

    "bla"=<current month multiplied by 30, plus the current day of the month>

    to the registry key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSconfig

    so that the worm keeps track of when it last updated itself.

    .
  6. Modifies the System.ini file by changing the line:

    "shell"="explorer.exe"

    to:

    "shell"="explorer.exe tskmg.exe"

  7. Modifies the Value data of:

    Shell

    in the registry key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon

    from:

    "explorer.exe"

    to:

    "explorer.exe tskmg.exe"

    so that the worm runs when you start Windows.

  8. Connects to a specific mIRC server to receive instructions. Some of the instructions allow for:
    • Listing/terminating currently active processes
    • Performing a Denial of Service (DoS) attack
    • Deleting or creating files and folders
    • Restarting the computer
    • Executing programs

    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: Kevin Ha

    Discovered: December 19, 2003
    Updated: February 13, 2007 12:15:22 PM
    Also Known As: Backdoor.Spyboter.gen [KAV]
    Type: Worm
    Systems Affected: Windows


    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. Restart the computer in Safe mode with command prompt.
    4. Delete the values that were added to the registry. Restart the computer.
    5. Run a full system scan and delete all the files detected as W32.HLLW.Warpigs.C.
    6. Edit the modified System.ini file. (Windows 95/98/Me).
    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:
    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 with command prompt
    1. Shut down the computer and turn off the power.
    2. Wait at least 30 seconds.
    3. Follow the instructions for your operating system:
      • Windows XP: Restart the computer. The computer begins processing a set of instructions known as the Basic Input/Output System (BIOS). The information displayed depends on the BIOS manufacturer. Some computers display a progress bar that refers to the word BIOS, while others may not display any indication that this process is occurring. As soon as the BIOS has finished loading, begin tapping the F8 key on your keyboard. Continue to do so until the Windows XP Advanced Options menu appears.
      • Windows 2000: Restart the computer. When you see the black and white Starting Windows bar at the bottom of the screen, start tapping the F8 key. The Windows 2000 Advanced Options Menu appears.

    4. Using the up and down arrow keys, select Safe mode with command prompt, and then press Enter. After some time, the words Safe Mode will appear in all four corners of the screen. Continue to wait until a command prompt appears. When it does, proceed to the next section.

    4. Deleting the value from the registry

    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. At the command prompt, type the following, and then press Enter:

      Regedit

    2. Navigate to the key:

      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    3. In the right pane, delete the value:

      "winsockdriver"="tskmg.exe"

    4. Navigate to the key:

      HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce

    5. In the right pane, delete the value:

      "winsockdriver"="tskmg.exe"

    6. Navigate to the key:

      HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon

    7. In the right pane, double-click:

      Shell

    8. Change:

      "explorer.exe tskmg.exe"

      to:

      "explorer.exe"

    9. Exit the Registry Editor.
    10. Restart the computer and allow it to start normally.

    5. 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.
    2. Run a full system scan.
    3. If any files are detected as infected with W32.HLLW.Warpigs.C, click Delete.

    6. Editing the modified 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 Win.ini file that you need to edit. If this backup copy exists, it will be in the C:\Windows\Recent 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:\Windows\Recent 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:\windows\system.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 tskmg.exe

    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.


    Writeup By: Kevin Ha