W32.Dumaru.Y@mm

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Discovered: January 23, 2004
Updated: February 13, 2007 12:16:37 PM
Also Known As: W32/Dumaru.y@MM [McAfee], I-Worm.Dumaru.j [Kaspersky], Win32.Dumaru.Y [Computer Assoc, W32/Dumaru-Y [Sophos], WORM_DUMARU.Y [Trend]
Type: Worm
Systems Affected: Windows



W32.Dumaru.Y@mm is a multi-threaded, mass-mailing worm that opens a backdoor, runs a keylogger, and attempts to steal personal information. It is similar to the W32.Dumaru.M@mm worm

This worm uses its own SMTP engine to spread to the email addresses it finds in the files on the infected system.

The email has the following characteristics:

From:  "Elene" <F**KENSUICIDE@HOTMAIL.COM>  (censored)
Subject: Important information for you. Read it immediately !
Message:
Hi !
Here is my photo, that you asked for yesterday.
Attachment: Myphoto.zip

The attachment is a zip file that contains the worm executable as Myphoto.jpg   <spaces>  .exe. (There are 56 spaces between ".jpg" and ".exe".)

This worm is packed with FSG.


Antivirus Protection Dates

  • Initial Rapid Release version January 26, 2004
  • Latest Rapid Release version January 26, 2018 revision 004
  • Initial Daily Certified version January 26, 2004
  • Latest Daily Certified version January 26, 2018 revision 009
  • Initial Weekly Certified release date January 26, 2004

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

Writeup By: Heather Shannon

Discovered: January 23, 2004
Updated: February 13, 2007 12:16:37 PM
Also Known As: W32/Dumaru.y@MM [McAfee], I-Worm.Dumaru.j [Kaspersky], Win32.Dumaru.Y [Computer Assoc, W32/Dumaru-Y [Sophos], WORM_DUMARU.Y [Trend]
Type: Worm
Systems Affected: Windows


When W32.Dumaru.Y@mm is executed, it does the following:

  1. Copies itself as these files:
    • %System%\l32x.exe
    • %System%\vxd32v.exe
    • %Startup%\dllxw.exe


      NOTES:
      • %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).
      • %Startup% is a variable: The worm locates the Windows startup folder and copies itself to that location. For example, this is C:\Windows\Start Menu\Programs\Startup in the Windows 98 system.

  2. Adds the value:

    "load32"="%System%\l32x.exe"

    to the registry key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    so that the worm runs when you start Windows.

  3. May create the registry key:

    HKEY_LOCAL_MACHINE\SOFTWARE\SARS

  4. Modifies the [boot] section of the system.ini file (Windows 95/98/Me only) as follows:

    [boot]
    shell=explorer.exe %System%\vxd32v.exe

    so that the worm runs when you start Windows 95/98/Me.

  5. 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 %Windir%\system32\vxd32v.exe"

    so that the worm runs when you start Windows NT/2000/XP.

  6. Retrieves email addresses from the files with the following extensions:
    • .htm
    • .wab
    • .html
    • .dbx
    • .tbb
    • .abd

      The email addresses will be saved in the file, %Windir%\winload.log.

  7. Creates the file, %Windir%\Temp\Zip.tmp, which contains the worm. Then, it uses its own SMTP engine to email the .zip file to the addresses it previously found.

    The email has the following characteristics:

    From: "Elene" <F**KENSUICIDE@HOTMAIL.COM> (censored)
    Subject: Important information for you. Read it immediately !
    Message:
    Hi !
    Here is my photo, that you asked for yesterday.
    Attachment: My photo.zip

  8. Launches multiple new threads, and each thread is designed for a specific purpose. The threads will do the following:
  • The first thread creates a WindowsHook, so that the worm gains control when certain actions occur on the system. This thread is designed to steal passwords, and it will log passwords as they are typed into Web forms and programs. They will be saved in the file, Vxdload.log.

    The worm may harvest passwords for a variety of programs; however, it specifically targets those for www.e-gold.com/. For any Web form on this site, the worm will begin logging all the keystrokes, which seems to be an attempt by the author of this worm to steal e-gold accounts.

  • Another thread, which this worm launches, is responsible for copying certain information from the clipboard into the file, Rundllx.sys.

  • If the worm does not find an Internet connection, only the first two threads are created. Then, the worm will go into an infinite loop, checking for an active Internet connection every 0.5 seconds. If it does find an active Internet connection, it will launch several more threads.

  • The next two threads that this worm launches will open ports on the system and wait for incoming connections. One thread will listen on TCP port 10000, and the other one on TCP port 2283.

  • The worm will periodically check the size of the files it uses for logging stolen information, and when sufficient in size, the log files will be emailed to a hard-coded email address.

  • As this worm runs two backdoor threads, an attacker could access the system and gain full control, as well as use an infected computer as a relay.


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: Heather Shannon

Discovered: January 23, 2004
Updated: February 13, 2007 12:16:37 PM
Also Known As: W32/Dumaru.y@MM [McAfee], I-Worm.Dumaru.j [Kaspersky], Win32.Dumaru.Y [Computer Assoc, W32/Dumaru-Y [Sophos], WORM_DUMARU.Y [Trend]
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. Do one of the following:
    • Windows 95/98/Me: Restart the computer in Safe mode.
    • Windows NT/2000/XP: End the malicious process.
  4. Run a full system scan and delete all the files detected as W32.Dumaru.Y@mm.
  5. Reverse the changes made to the registry.
  6. Edit the System.ini file (Windows 95/98/Me).
For 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:
Note: When you are completely finished with the removal procedure and you are satisfied that the threat has been removed, re-enable 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. 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 ending the malicious process
    Windows 95/98/Me
    Shut down the computer and turn off the power. Wait for at least 30 seconds, and then restart the computer in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."

    Windows NT/2000/XP
    To end the malicious process:
    1. Press Ctrl+Alt+Delete once.
    2. Click Task Manager.
    3. Click the Processes tab.
    4. Double-click the Image Name column header to alphabetically sort the processes.
    5. Scroll through the list and look for "vxd32v.exe," "l32x.exe," or "dllxw.exe."
    6. If you find one of these files, click it, and then click End Process.
    7. Exit the Task Manager.
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.
  2. Run a full system scan.
  3. If any files are detected as infected with W32.Dumaru.Y@mm, click Delete.

5. Reversing the changes made to 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. 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_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

  4. In the right pane, delete the value:

    "load32"="%System%\l32x.exe""

  5. Do one of the following:
    • If you are using Windows 95/98/Me, proceed to step i.
    • If you are using Windows NT/2000/Xp, proceed to step f.

  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 %Windir%\system32\vxd32v.exe"

    to:

    "explorer.exe"

  9. Exit the Registry Editor.

  10. Restart the computer back into Normal mode. For instructions, read the section on returning to Normal mode in the document, "How to start the computer in Safe Mode."


6. 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:\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 C:\WINDOWS\SYSTEM\vxd32v.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: Heather Shannon