W32.Nolor@mm

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Discovered: April 28, 2003
Updated: February 13, 2007 12:00:37 PM
Also Known As: W32/Lovelorn@MM [McAfee], WORM_LOVELORN.A [Trend], Win32.Lovelorn.A [CA], I-Worm.Lovelorn [KAV], W32/Cailont-A [Sophos]
Type: Worm, Virus
Systems Affected: Windows


W32.Nolor@mm is a mass-mailing worm that uses its own SMTP engine to spread itself. The email will have a variable subject line and an attachment with the filename, *.Kiss.ok.exe or *.htm.

W32.Nolor@mm is also a file infector that encrypts the host file, and then prepends itself to the host file.

This threat is written in the Borland C++ programming language.

Antivirus Protection Dates

  • Initial Rapid Release version April 28, 2003
  • Latest Rapid Release version March 23, 2017 revision 037
  • Initial Daily Certified version April 28, 2003
  • Latest Daily Certified version March 23, 2017 revision 041
  • Initial Weekly Certified release date April 30, 2003

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

Writeup By: Kaoru Hayashi

Discovered: April 28, 2003
Updated: February 13, 2007 12:00:37 PM
Also Known As: W32/Lovelorn@MM [McAfee], WORM_LOVELORN.A [Trend], Win32.Lovelorn.A [CA], I-Worm.Lovelorn [KAV], W32/Cailont-A [Sophos]
Type: Worm, Virus
Systems Affected: Windows


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

  1. Copies itself to the %System% folder as the following:
    • Explorer.exe
    • Kernel32.exe
    • Netdll.dll
    • Serscg.dll

      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 following files in the %System% folder:
    • Setup.htm, which creates the viral file, %Temp%\Temp.exe, when executed.
    • Bsbk.dll, which is a MIME64-encoded copy of Setup.htm.
    • Netsn.dll, which is a MIME64-encoded copy of the dropped %System%\Explorer.exe.

      NOTE: %Temp% is a variable. The worm locates the Windows temporary folder, and then copies itself to that location. For example, this can be C:\Windows\Temp (Windows 98) or C:\Documents and Settings\<current username>\local settings\Temp (Windows 2000).

  3. Attempts to copy itself as A:\NQH_Kiss_you.exe and %Startup%\Findfast.exe.

  4. Adds the value:

    "explorer"="%System%\explorer.exe"

    to the registry key:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

  5. Searches for a random .htm file on the infected system and creates a copy of itself in the same folder, using the same filename with the extension .Kiss.ok.exe.

    For example, if the worm finds the file, C:\My Documents\Shared Documents\test.htm, it may create a file, C:\My Documents\Shared Documents\test.Kiss.ok.exe, which is a copy of the worm.

  6. Terminates any processes that contain the following strings:

    BKAV
    NAVA

  7. May infect the Portable Executable (PE) files. The worm encrypts and prepends its viral code to the file, increasing its size by 102,400 bytes. The infected file uses the same icon as the original file.

  8. Retrieves the IP address of the SMTP server, current user's username, and email address from the registry.

  9. Searches the IP addresses from the Internet cache, .dbx files, and .htm files. The worm creates the text file, %System%\Mssys.dll, to keep the email addresses it finds.

  10. Uses its own SMTP engine to send itself to all the email addresses it finds.
    The email will be in the following format:

    Subjects: Re:baby!your friend send this file to you !
    Message: Read this file

    Subjects: HELP??-
    Message: Help...

    Subjects: Re:Get Password  mail...
    Message: Enjoy

    Subjects: There're some Passwords here
    Message: Read File attach .

    Subjects:  Re:Binladen_Sexy.jpg
    Message: run File Attach to extract:BinladenSexy.jpg...

    Subjects: The Sexy story and 4 sexy picture of BINLADEN !
    Message: Enjoy! BINLADEN:SEXY..

    Subjects: Re:I Love You...OKE!
    Message: Souvenir for you from file attach...

    Subjects: A Greeting-card for you .
    Message: See the Greeting-card .

    Subjects: Re:Kiss you..^@^
    Message: Read file attach

    Subjects: Guide to <offensive word>...
    Message: I like Sexy with you.

    Subjects: Re:Baby! 2000USD,Win this game...
    Message: Play the game from file attach

    Subjects: Help
    Message: Help.

    Attachment: Attachment is one of the following,

    *.Kiss.ok.exe
    *.HTM

    Where * varies from email to email.

    From: The worm may spoof this field of the email as one of the following:
    • love_lorn@yahoo.com
    • thuyquyen@yahoo.com
    • lovelorn@yahoo.com
    • User's default email address
    • The email addresses it found from the Internet cache, .eml files or .dbx files


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: Kaoru Hayashi

Discovered: April 28, 2003
Updated: February 13, 2007 12:00:37 PM
Also Known As: W32/Lovelorn@MM [McAfee], WORM_LOVELORN.A [Trend], Win32.Lovelorn.A [CA], I-Worm.Lovelorn [KAV], W32/Cailont-A [Sophos]
Type: Worm, Virus
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. Update the virus definitions.
  2. Restart the computer in Safe mode or VGA mode.
  3. Run a full system scan and repair or delete all the files detected as W32.Nolor@mm.
  4. Delete the value that was added to the registry.
For specific details on each of these steps, read the following instructions.

1. 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.

2. 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.

3. Scanning for and repairing 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.Nolor@mm, click Repair. Delete any files that cannot be repaired and replace them from backup copies, if necessary.


4. 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

  4. In the right pane, delete the value:

    "explorer"="%System%\explorer.exe"

  5. Exit the Registry Editor.


Writeup By: Kaoru Hayashi