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  3. W32.Erkez.D@mm

W32.Erkez.D@mm

Risk Level 2: Low

Discovered:
December 14, 2004
Updated:
February 13, 2007 12:58:59 PM
Also Known As:
Win32.Zafi.D [Computer Associa, Zafi.D [F-Secure], Email-Worm.Win32.Zafi.d [Kaspe, W32/Zafi.d@MM [McAfee], W32/Zafi.D.worm [Panda], W32/Zafi-D [Sophos], WORM_ZAFI.D [Trend Micro]
Type:
Worm
Systems Affected:
Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP

Once W32.Erkez.D@mm is executed, it performs the following actions:
  1. Creates the following files:

    • %System%\Norton Update.exe
    • C:\s.cm (A log file.)

      Note: %System% is a variable that refers to the System folder. 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 multiple copies of itself in the %System% folder as .dll files with eight-character, random file names.

  3. Attempts to create the following files in folders with the string "shar", "upload", or "music" in their name that it finds in the fixed drives C through H:

    • winamp 5.7 new!.exe
    • ICQ 2005a new!.exe


  4. Creates the following mutex named "Wxp4", so that only one copy of the worm is run on the infected computer.

  5. Adds the value:

    "Wxp4" = "%System%\Norton Update.exe"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

    so that the worm executes every time Windows starts.

  6. Creates the following registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Wxp4

    where information about the worm is stored.

  7. Displays the following error message:

    Title: CRC: 04F7Bh
    Message: Error in packed file!

  8. Terminates processes with the following strings in their name:

    • reged
    • msconfig
    • task

  9. Attempts to connect to the microsoft.com domain.

  10. Opens a back door on TCP port 8181 and listens for commands from a remote attacker.

  11. Searches for .exe files in folders containing the following strings:

    • syman
    • viru
    • trend
    • secur
    • panda
    • cafee
    • sopho
    • kasper

      and attempts to terminate the processes for any of the executables found.

  12. Gathers email addresses from the infected computer and stores them in randomly named .dll files in the %System% folder.

  13. Retrieves email addresses from the Windows Address Book and from files with the following extensions:

    • .htm
    • .wab
    • .txt
    • .dbx
    • .tbb
    • .asp
    • .php
    • .sht
    • .adb
    • .mbx
    • .eml
    • .pmr
    • .fpt
    • .inb

      The worm avoids email addresses containing the following strings:

    • yaho
    • google
    • win
    • use
    • info
    • help
    • admi
    • ebm
    • micro
    • msn
    • hotm
    • suppor
    • syman
    • viru
    • trend
    • secur
    • panda
    • cafee
    • sopho
    • kasper

  14. Sends a copy of the worm to email addresses gathered from the computer, using its own SMTP engine.

    The email contains the following characteristics:

    From:
    (Spoofed)

    Subject:
    (One of the following)

    • Merry Christmas!
    • boldog karacsony...
    • Feliz Navidad!
    • ecard.ru
    • Christmas Kort!
    • Christmas Vykort!
    • Christmas Postkort!
    • Christmas postikorti!
    • Christmas - Kartki!
    • Weihnachten card.
    • Prettige Kerstdagen!
    • Christmas pohlednice
    • Joyeux Noel!
    • Buon Natale!

      Message:
      (One of the following)

    • Happy HollyDays!
      :) [Sender]
    • Kellemes Unnepeket!
      :) [Sender]
    • Feliz Navidad!
      :) [Sender]
    • :) [Sender]
    • Glaedelig Jul!
      :) [Sender]
    • God Jul!
      :) [Sender]
    • Iloista Joulua!
      :) [Sender]
      Naujieji Metai!
      :) [Sender]
    • Wesolych Swiat!
      :) [Sender]
    • Fröhliche Weihnachten!
      :) [Sender]
    • Prettige Kerstdagen!
      :) [Sender]
    • Veselé Vánoce!
      :) [Sender]
    • Joyeux Noel!
      :) [Sender]
    • Buon Natale!
      :) [Sender]


      Attachment: (Variable name with one of the following extensions)

    • .bat
    • .cmd
    • .com
    • .pif
    • .zip

      The following is an example of the email that the worm sent:



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: John Canavan
Summary| Technical Details| Removal

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