Discovered: April 19, 2004
Updated: February 13, 2007 12:21:35 PM
Also Known As: I-Worm.Zafi [Kaspersky], W32/Zafi@MM [McAfee], W32/Zafi-A [Sophos], WORM_ZAFI.A [Trend], Win32.Zafi.A [Computer Associa
Type: Worm
Systems Affected: Windows

W32.Erkez.A@mm is a mass-mailing worm that sends itself to the email addresses found on an infected computer.

  • The worm has an MD5 value of 0X3D18BAED7648F91B8528CD4AB57931A4.
  • Symantec Consumer products that support the Worm Blocking functionality automatically detect this threat as it attempts to spread.

Antivirus Protection Dates

  • Initial Rapid Release version April 19, 2004
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version April 19, 2004
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date April 19, 2004

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

Writeup By: Paul Mangan

Discovered: April 19, 2004
Updated: February 13, 2007 12:21:35 PM
Also Known As: I-Worm.Zafi [Kaspersky], W32/Zafi@MM [McAfee], W32/Zafi-A [Sophos], WORM_ZAFI.A [Trend], Win32.Zafi.A [Computer Associa
Type: Worm
Systems Affected: Windows

When W32.Erkez.A@mm runs, it does the following:

  1. If the computer's date is May 1, 2004, it will display the following Hungarian text:

    Emberek! Magyarok szazezrei, millioi elnek naprol - napra, halnak ehen - szomjan,
    s szegenysegben hazankban! Mikozben jonehany felso parlamenti gazember
    millios vagyonokra tesz szert, mitsem torodve velunk.
    Latszat emberek iranyitanak, kik emelik fizetesunk, s ketszer annyi adot vonnak le,
    kik igazsagszolgaltatasrol regelnek, mikor a bunozoket es a novekvo agressziot vedik
    torvenyeikkel, kik inkabb Forma1-re pocsekoljak a penzt, mialatt hajlektalanok
    halnak meg naponta utcainkon, s korhazi betegek szenvednek szukseges muszerek nelkul.
    Hogy - hogy nem latja ezt senki ???? Miert nincs egy igaz magyar, ki vegre
    mar nem sajat erdekeit, hanem az orszag sulyos problemait helyezne eloterbe!!!
    Nem eleg akarni, s beszelni, meg szonoklatni a szepet,s jot,
    tenni-tenni-tenni kell, egyarant mindenkinek - mindenkiert!
    == HAZAFI == /Pecs,2004, (SNAF Team)/

  2. Terminates itself if the month is not April.

  3. Copies itself to the %System% folder as an eight-character, random file name with a .exe extension. It also creates the text files in the same folder with .dll extensions.

  4. Creates the registry key:


    to store the configuration information of the worm.

  5. Adds the value:

    "<random name>"="%system%\<random file name>.exe"

    to the registry key:


    so that the worm runs when you start Windows.

  6. Checks for an active Internet connection by querying http:/ /

  7. Attempts to end the following processes:
    • dfw.exe
    • fsav32.exe
    • fsbwsys.exe
    • fsgk32.exe
    • fsm32.exe
    • fssm32.exe
    • fvprotect.exe
    • mcagent.exe
    • navapw32.exe
    • navdx.exe
    • navstub.exe
    • navw32.exe
    • nc2000.exe
    • ndd32.exe
    • netarmor.exe
    • netinfo.exe
    • netmon.exe
    • nmain.exe
    • nprotect.exe
    • ntvdm.exe
    • ostronet.exe
    • outpost.exe
    • pccguide.exe
    • pcciomon.exe
    • regedit.exe
    • regedit32.exe
    • taskmgr.exe
    • tnbutil.exe
    • vbcons.exe
    • vbsntw.exe
    • vbust.exe
    • vsmain.exe
    • vsmon.exe
    • vsstat.exe
    • winlogon.exe
    • zonalarm.exe

  8. Searches for the email addresses in the files with the following extensions:
    • .htm
    • .wab
    • .txt
    • .dbx
    • .tbb
    • .asp
    • .php
    • .sht
    • .adb
    • .mbx
    • .eml
    • .pmr

      It avoids the email addresses containing the following substrings:
    • microsoft
    • vir
    • trendmicro
    • avp
    • f-prot
    • hotmail
    • gov
    • anti
    • panda
    • norton

      Note: The worm stores these email addresses in randomly named .dll files in the %System% folder.

  9. Generates the email addresses from random characters, to which it also sends itself.

  10. Randomly selects a recently typed URL from Internet Explorer's History folder and opens it in Internet Explorer.

  11. Sends an email that has the following characteristics:

    From: (One of the following)


    Subject: kepeslap erkezett!

    Tisztelt felhasználó!
    Önnek kópeslapja órkezett!
    A kópeslap feladója:  A lapot az alábbi cimen tudja megtekinteni:
    vagy a mellókelt internetlink kattintásával.
    Üdvözlettel: Matav e-card!



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: April 19, 2004
Updated: February 13, 2007 12:21:35 PM
Also Known As: I-Worm.Zafi [Kaspersky], W32/Zafi@MM [McAfee], W32/Zafi-A [Sophos], WORM_ZAFI.A [Trend], Win32.Zafi.A [Computer Associa
Type: Worm
Systems Affected: Windows

Removal using the W32.Erkez@mm Removal Tool
Symantec Security Response has developed a removal tool to clean the infections of W32.Erkez.A@mm. Use this removal tool first, as it is the easiest way to remove this threat.

Manual Removal
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 W32.Erkez.A@mm.
  5. 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:
Note: 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 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. To restart 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. 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.Erkez.A@mm, write down the file name, and then click Delete.

4. To delete the value from 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:


  4. In the right pane, delete the value that refers to any file detected as W32.Erkez.A@mm.

  5. Navigate to and delete the key:


  6. Exit the Registry Editor.

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

Writeup By: Paul Mangan