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Discovered: September 15, 2004
Updated: February 13, 2007 12:27:36 PM
Type: Worm
Systems Affected: Windows

W32.Mexer.E@mm is a mass-mailing worm that also spreads through several file-sharing networks.

Antivirus Protection Dates

  • Initial Rapid Release version September 15, 2004
  • Latest Rapid Release version December 12, 2016 revision 025
  • Initial Daily Certified version September 15, 2004
  • Latest Daily Certified version December 13, 2016 revision 001
  • Initial Weekly Certified release date September 15, 2004

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

Writeup By: Paul Mangan

Discovered: September 15, 2004
Updated: February 13, 2007 12:27:36 PM
Type: Worm
Systems Affected: Windows

When W32.Mexer.E@mm is executed, it performs the following actions:

  1. Creates the folder %System%\sys32.

    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 the following copies of itself in the %System%\sys32 folder:
    • Ruby13.exe
    • Nero Burning ROM v6.3 Ultra: Enterprise edition key.exe
    • Counter-Strike, Condition Zero: Activation Key.exe
    • icqbomber.exe
    • BurnDvds.exe
    • Dvd Ripper.exe
    • Dvd To Vcd.exe
    • Easy Dvd Ripper.exe
    • EZ Dvd Ripper.exe
    • Nimo Codec Pack Updater.exe
    • Xvid Codec Installer.exe
    • Starcraft + Broodwar 1.10 map hack.exe
    • Starcraft + Broodwar 1.10 no-cd hack.exe
    • Diablo 2 map hack.exe
    • Diablo 2 no-cd hack.exe
    • Jamella's Diablo 2 hero editor.exe
    • Warcraft 3 map hack.exe
    • Warcraft 3 stat hack.exe
    • Warcraft 3 no-cd hack.exe
    • Warcraft 3 Frozen Throne map hack.exe
    • Warcraft 3 Frozen Throne cd-cd hack.exe
    • The Frozen Throne map hack.exe
    • Counterstrike hacks.exe
    • Counterstrike aim hack.exe
    • Crack McAfee 7.exe
    • Crack Norton 3000.exe
    • Borland KeyGens.exe
    • SophosCrackAllVersion.exe
    • PANDA.lusers.exe
    • PANDA.AVers.lusers.exe
    • MP3 encoder decoder V1.8.exe
    • Cisco Certification Test.exe
    • MSCE Certification Test.exe
    • Windows Nt Certification Test.exe
    • XBOX X-Fer Ripper and Transfer.exe
    • Information.exe
    • EBAY.exe
    • VISA.EXE

  3. Creates copies of itself in the %System%\sys32 folder, using the file,names created by appending one of the following substrings:
    • Keygen.exe
    • Serial.exe
    • NoCD.exe
    • Crack.exe

      to each of the following:
    • Norton AntiVirus 2004 Pro Activation Key &
    • Microsoft Windows XP Professional
    • Adobe Photoshop CS and ImageReady CS 8.0
    • Zone Alarm 5.0 pro
    • Harry Potter and the Prisoner of Azkaban KeyGen and
    • Norton Internet Security 2004 Keygen &
    • All Adobe Products
    • All Macromedia Products
    • All Microsoft Products
    • Divx Pro 5.1
    • Dvd Plus
    • Dvd Wizard Pro
    • Dvd Xcopy
    • DvdCopyOne
    • DvdToVcd
    • Easy Dvd creator
    • Nero Burning Rom
    • BitDefender
    • Nod32
    • Ipswich Town Official Management Game -
    • Bridge Baron 13
    • American Conquest -
    • Grom -
    • Slot City 3
    • Command and Conquer Generals
    • Nascar Racing 2003 Season
    • Eonix Realm Of Hepmia -
    • I Was An Atomic Mutant -
    • Fetish Fighters -
    • Battlefield 1942 The Road to Rome -
    • The Campaigns of La Grande Armee -
    • Unreal II The Awakening -
    • The Emperors Mahjong -
    • Sim City 4 -
    • Private Nurse -
    • Impossible Creatures -
    • Test Drive -
    • Shadow of Memories -
    • World Of Outlaws Sprint Car Racing 2002 -
    • Tombstone 1882 -
    • Airport Tycoon II -
    • Apache AH-64 Air Assault -
    • A+ Certification Test.exe
    • Serious Sam - Gold Edition -
    • IGI-2 Covert Strike -
    • Tom Clancys Splinter Cell -
    • Robot Arena Design And Destroy -
    • Freelancer -
    • Battlefield Vietnam -
    • Deus Ex -
    • Forbidden Siren -
    • Doom 3 -
    • WinRAR 3
    • WinACE
    • WinZIP 9
    • Norton AntiVirus 2005
    • Shrek 2
    • Spider-Man 2
    • Spellforce - Breath of Winter
    • Norton Internet Security 2005 Pro
    • Norton Internet Security 2004 Pro
    • Symantec Internet Secutiy 2005
    • Symantec Antivirus 2005
    • Harry Potter und der Gefangene von Askaban
    • Kazaa all
    • Windows Server 2003
    • Office XP Universal

  4. Adds the value:


    to the registry keys:


    so that the worm is executed every time Windows starts.

  5. Adds the value:


    to the registry keys:


    to spread using the iMesh and KaZaA peer-to-peer file-sharing networks.

  6. Gathers the email addresses from the files with the following extensions:
    • .wab
    • .dbx
    • .htm
    • .sht
    • .txt
    • .doc
    • .rtf

      The worm avoids the email addresses that contain the following substrings:
    • supp
    • webm
    • viru
    • newv
    • kasp
    • micr
    • root
    • admi
    • host

  7. Sends itself to the email addresses found, using its own SMTP engine. The email has the following characteristics:

    • EBAY Information
    • VISA Information
    • Provider Information
    • Your Crack
    • Internet Information

      Message body:
    • EBAY Installer...
    • Security Tool...
    • Here is your crack!
    • New account data...

      Attachment: Selected randomly from the files in C:\sysnet and the file is 30,720 bytes long.

  8. The worm also displays a dialog box with the title "Ruby V1.3, (c)BI 16.08.2004" and text "Fight against MICROSOFT and make a virus!"


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: Paul Mangan

Discovered: September 15, 2004
Updated: February 13, 2007 12:27:36 PM
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.

Important: On computers running Norton AntiVirus 2005 or later, the QuickScan tool will automatically search for and remove malicious threats when new virus definitions are downloaded. While every effort has been made to ensure that the QuickScan tool removes all traces of a malicious threat from an infected computer, we advise that you confirm that all the files and registry entries have been removed. We recommend following the manual removal steps and deleting any threat-related files or registry entries remaining on the computer.

  1. Disable System Restore (Windows Me/XP).
  2. Update the virus definitions.
  3. Run a full system scan and delete all the files detected as W32.Mexer.E@mm.
  4. Delete the value that was added to the registry.
For specific details on each of these steps, read the following instructions.

1. To disable 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:

When you are completely finished with the removal procedure and 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. To update 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 daily. 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. To scan for and delete 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.Mexer.E@mm, click Delete.

    If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix this, run the scan in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode." Once you have restarted in Safe mode, run the scan again.

    (After the files are deleted, you can leave the computer in Safe mode and proceed with section 4. When that is done, restart the computer in Normal mode.)

4. To delete the value from the registry

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 > Run.
  2. Type regedit

    Then click OK.

  3. Navigate to the key:


  4. In the right pane, delete the value:


  5. Navigate to the key:


  6. In the right pane, delete the value:


  7. Exit the Registry Editor.

Writeup By: Paul Mangan