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Discovered: February 10, 2005
Updated: February 13, 2007 12:33:18 PM
Also Known As: Email-Worm.Win32.Mydoom.ak [Ka, W32/Mydoom.ba@MM [McAfee]
Type: Worm
Systems Affected: Windows

W32.Mydoom.AU@mm is a mass-mailing worm that uses its own SMTP engine to send itself to email addresses that it gathers from a compromised computer. This worm is a minor variant of W32.Mydoom.AM@mm .

Removing entries from the Hosts file
If this threat has modified the Windows Hosts file, there are two ways to remove these entries:

  • Install and run the current version of LiveUpdate. This will remove only the entries that refer to Symantec domains.
  • Manually edit the Hosts file and remove all the entries that the worm added.

To run the current version of LiveUpdate
  1. Click download LiveUpdate.

    If you are not reading this Web page on the computer that is getting the error notice, the address for downloading the file is:


    If necessary, you can type this address into the address bar of the problem computer. Changes to the Hosts file will not stop you from getting to this site.

  2. Save the file to the Windows desktop.
  3. Double-click the lusetup.exe icon on the desktop to install LiveUpdate.
  4. Run LiveUpdate.
  5. Did you see the message "LU1860: LiveUpdate has detected a potential security compromise on your computer"?
    • If you did, let LiveUpdate "Remove these entries from the hosts files" (Recommended).
      This should allow LiveUpdate to run.
    • If you did not, that was not the cause of the problem. Return to the Removal section.

To manually edit the Hosts file and remove all the entries that the worm added

Note: The location of the Hosts file may vary and some computers may not have this file. For example, if the file exists in Windows 98, it will usually be in C:\Windows; and it is located in the C:\WINNT\system32\drivers\etc folder in Windows 2000. There may also be multiple copies of this file in different locations.

Follow the instructions for your operating system:
  • Windows 95/98/Me/NT/2000
    1. Click Start, point to Find or Search, and then click Files or Folders.
    2. Make sure that "Look in" is set to (C:) and that "Include subfolders" is checked.
    3. In the "Named" or "Search for..." box, type:


    4. Click Find Now or Search Now.
    5. For each Hosts file that you find, right-click the file, and then click Open With.
    6. Deselect the "Always use this program to open this program" check box.
    7. Scroll through the list of programs and double-click Notepad.
    8. When the file opens, delete all the entries in step 10 of the "Technical Details" section.
    9. Close Notepad and save your changes when prompted.

  • Windows XP
    1. Click Start > Search.
    2. Click All files and folders.
    3. In the "All or part of the file name" box, type:


    4. Verify that "Look in" is set to "Local Hard Drives" or to (C:).
    5. Click More advanced options.
    6. Check Search system folders.
    7. Check Search subfolders.
    8. Click Search.
    9. Click Find Now or Search Now.
    10. For each Hosts file that you find, right-click the file, and then click Open With.
    11. Deselect the Always use this program to open this program check box.
    12. Scroll through the list of programs and double-click Notepad.
    13. When the file opens, delete all the entries in step 10 of the "Technical Details" section.
    14. Close Notepad and save your changes when prompted.

Antivirus Protection Dates

  • Initial Rapid Release version February 10, 2005
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version February 10, 2005
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date February 16, 2005

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

Writeup By: Kaoru Hayashi

Discovered: February 10, 2005
Updated: February 13, 2007 12:33:18 PM
Also Known As: Email-Worm.Win32.Mydoom.ak [Ka, W32/Mydoom.ba@MM [McAfee]
Type: Worm
Systems Affected: Windows

Once executed, W32.Mydoom.AU@mm performs the following actions:

  1. Creates the files:

    • %System%\lsasrv.exe
    • %System%\version.ini
    • [path of execution]\hserv.sys

      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 mutex -=RTSW.Smash 0a2a0=-, so that only one instance of the worm runs on the compromised computer.

  3. Adds the value:

    "lsass" = "%System%\lsasrv.exe"

    to the registry subkey:


    so that it is executed every time Windows starts.

  4. Modifies the value:

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

    in the registry subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon

    so that it is executed every time Windows starts.

  5. Creates a text file named %Temp%\Mes#wtelw.txt, which contains only garbage data. The worm uses Notepad to open the file and display the garbage data.

    Note: %Temp% is a variable that refers to the Windows temporary folder. By default, this is C:\Windows\TEMP (Windows 95/98/Me/XP) or C:\WINNT\Temp (Windows NT/2000).

  6. Gathers email addresses from the Windows Address Book and from files with the following extensions:

    • .wab
    • .pl
    • .adb
    • .tbb
    • .dbx
    • .asp
    • .php
    • .sht
    • .htm
    • .txt

      avoids sending itself to an email address that contains one of the following strings:

    • accoun
    • certific
    • listserv
    • ntivi
    • support
    • icrosoft
    • admin
    • page
    • the.bat
    • gold-certs
    • feste
    • submit
    • not
    • help
    • service
    • privacy
    • somebody
    • soft
    • contact
    • site
    • rating
    • bugs
    • you
    • your
    • someone
    • anyone
    • nothing
    • nobody
    • noone
    • webmaster
    • postmaster
    • samples
    • info
    • root
    • mozilla
    • utgers.ed
    • tanford.e
    • pgp
    • acketst
    • secur
    • isc.o
    • isi.e
    • ripe.
    • arin.
    • sendmail
    • rfc-ed
    • ietf
    • iana
    • usenet
    • fido
    • linux
    • kernel
    • google
    • ibm.com
    • fsf.
    • gnu
    • mit.e
    • bsd
    • math
    • unix
    • berkeley
    • foo.
    • .mil
    • gov.
    • .gov
    • ruslis
    • nodomai
    • mydomai
    • example
    • inpris
    • borlan
    • sopho
    • panda
    • hotmail
    • msn.
    • icrosof
    • syma
    • avp
    • .edu
    • abuse
    • www
    • fcnz
    • spm

  7. Uses its own SMTP engine to send itself to the email addresses that it finds. The email will have the following characteristics:

    From: Composes a fake address in the format [First name][Random last name]@[Domain]

    Where [First name] is one of the following:

    • Joseph
    • Ronald
    • Hannah
    • Kimberly
    • Maria
    • George
    • Charles
    • Len
    • Cissi
    • Sandra
    • Jennifer
    • Hans
    • Richard
    • Lee
    • Emily
    • Helen
    • Elizabeth
    • Donald
    • David
    • Harris
    • Nicholas
    • Betty
    • Barbara
    • Mark
    • William
    • Martin
    • Ethan
    • Karen
    • Linda
    • Paul
    • Michael
    • Edward
    • Cynthia
    • Nancy
    • Patricia
    • Daniel
    • Robert
    • Olivia
    • Angela
    • Dorothy
    • Kevin
    • Christopher
    • John
    • Josefine
    • Melissa
    • Susan
    • Anthony
    • Thomas
    • James

      and [Domain] is one of the following:

    • compuserve.com
    • juno.com
    • earthlink.net
    • yahoo.co.uk
    • hotmail.com
    • yahoo.com
    • msn.com
    • aol.com

      One of the following:

    • Attention!!!
    • Do not reply to this email
    • Error
    • Good day
    • hello
    • Mail Delivery System
    • Mail Transaction Failed
    • Server Report
    • Status

      One of the following filenames:

    • body
    • message
    • docs
    • data
    • file
    • rules
    • doc
    • readme
    • document

      with one of the following extensions:

    • .bat
    • .cmd
    • .exe
    • .scr
    • .pif
    • .zip

      Message Body:
      One of the following:

    • Mail transaction failed. Partial message is available
    • The message contains Unicode characters and has been sent as a binary attachment.
    • The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
    • Mail transaction failed. Partial message is available.
    • Thank you for registering at WORLDXXXPASS.COM
      All your payment info, login and password you can find in the attachment file.
      It's a real good choise to go to WORLDXXXPASS.COM
    • Attention! New self-spreading virus!
      Be careful, a new self-spreading virus called "RTSW.Smash" spreading very fast via e-mail and P2P networks. It's about two million people infected and it will be more.
      To avoid your infection by this virus and to stop it we provide you with full information how to protect yourself against it and also including free remover. Your can find it in the attachment.
      c 2004 Networks Associates Technology, Inc. All Rights Reserved
    • New terms and conditions for credit card holders
      Here a new terms and conditions for credit card holders using a credit cards for making purchase in the Internet in the attachment. Please, read it carefully. If you are not agree with new terms and conditions do not use your credit card in the World Wide Web.
      Thank you,
      The World Bank Group
      c 2004 The World Bank Group, All Rights Reserved
    • Attention! Your IP was logged by The Internet Fraud Complaint Center
      Your IP was logged by The Internet Fraud Complaint Center. There was a fraud attempt logged by The Internet Fraud Complaint Center from your IP. This is a serious crime, so all records was sent to the FBI. All information you can find in the attachment. Your IP was flagged and if there will be anover attemption you will be busted.
      This message is brought to you by the Federal Bureau of Investigation and the National White Collar Crime Center
    • You have visited illegal websites
      I have a big list of the websites you surfed
    • You think it's funny? You are stupid idiot!!! I'll sendthe attachment to your ISP and then I'll be watchinghow you will go to jail, punk!!!
    • Your credit card was charged for $500 USD. For additional information see the attachment
    • ESMTP [Secure Mail System #334]: Secure message is attached
    • Encrypted message is available
    • Delivered message is attached
    • Can you confirm it?
    • Binary message is available
    • am shocked about your document!
    • Are you a spammer? (I found your email on a spammer website!?!
    • Bad Gateway: The message has been attached
    • Here is your documents you are requested

  8. Copies itself to shared folders of Kazaa, Morpheus, iMesh, eDonkey, or LimeWire. The file has one of the following names with either a bat, pif, scr, or exe extension:

    • porno
    • NeroBROM6.3.1.27
    • avpprokey
    • Ad-awareref01R349
    • winxp_patch
    • adultpasswds
    • dcom_patches
    • K-LiteCodecPack2.34a
    • activation_crack
    • icq2004-final
    • winamp5

  9. Attempts to disable the following processes, including firewall and antivirus applications:

    • i11r54n4.exe
    • irun4.exe
    • d3dupdate.exe
    • rate.exe
    • ssate.exe
    • winsys.exe
    • winupd.exe
    • SysMonXP.exe
    • bbeagle.exe
    • Penis32.exe
    • teekids.exe
    • MSBLAST.exe
    • mscvb32.exe
    • sysinfo.exe
    • PandaAVEngine.exe
    • taskmon.exe
    • wincfg32.exe
    • outpost.exe
    • zonealarm.exe
    • navapw32.exe
    • navw32.exe
    • zapro.exe
    • msblast.exe
    • netstat.exe

  10. Appends the following lines to the Hosts file to prevent access to antivirus-related Web sites: www.symantec.com securityresponse.symantec.com symantec.com www.sophos.com sophos.com www.mcafee.com mcafee.com liveupdate.symantecliveupdate.com www.viruslist.com viruslist.com www.f-secure.com f-secure.com kaspersky.com kaspersky-labs.com www.avp.com avp.com www.kaspersky.com www.networkassociates.com networkassociates.com www.ca.com ca.com mast.mcafee.com www.my-etrust.com my-etrust.com download.mcafee.com dispatch.mcafee.com secure.nai.com www.nai.com nai.com update.symantec.com updates.symantec.com us.mcafee.com liveupdate.symantec.com customer.symantec.com rads.mcafee.com www.trendmicro.com trendmicro.com www.grisoft.com grisoft.com


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: February 10, 2005
Updated: February 13, 2007 12:33:18 PM
Also Known As: Email-Worm.Win32.Mydoom.ak [Ka, W32/Mydoom.ba@MM [McAfee]
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.

  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.Mydoom.AU@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.

    Note: If you see an error, such as LU1418, when you try to run LiveUpdate and you cannot get the Web site hosting the Intelligent Updater, it is likely that the worm has modified the Hosts file. You can either download and install LiveUpdate 2.5, which can remove Symantec entries from that file, or you can edit it yourself. See the instructions for both in the "Additional Information" section below.

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.Mydoom.AU@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, restart the computer in Normal mode and proceed with section 4.

4. To delete the value from the registry
Important: 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 subkeys 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 subkey:


  4. In the right pane, delete the value:

    "lsass" = "%System%\lsasrv.exe"

  5. Navigate to the subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon

  6. In the right pane, delete the value:

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

  7. Exit the Registry Editor.

Writeup By: Kaoru Hayashi