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Discovered: April 12, 2005
Updated: February 13, 2007 1:03:54 PM
Also Known As: Backdoor.Win32.IRCBot.ao [Kasp, W32/Sdbot.worm.gen.i [McAfee], WORM_SDBOT.BKW [Trend Micro]
Type: Worm
Systems Affected: Windows

W32.Spybot.NLX is a worm that has distributed denial of service and back door capabilities.

The worm spreads through network shares protected by weak passwords and by exploiting the following vulnerabilities:

Antivirus Protection Dates

  • Initial Rapid Release version April 12, 2005
  • Latest Rapid Release version April 12, 2005
  • Initial Daily Certified version April 12, 2005
  • Latest Daily Certified version April 12, 2005
  • Initial Weekly Certified release date April 13, 2005

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

Writeup By: John Canavan

Discovered: April 12, 2005
Updated: February 13, 2007 1:03:54 PM
Also Known As: Backdoor.Win32.IRCBot.ao [Kasp, W32/Sdbot.worm.gen.i [McAfee], WORM_SDBOT.BKW [Trend Micro]
Type: Worm
Systems Affected: Windows

When W32.Spybot.NLX is executed, it performs the following actions:

  1. Copies itself as %Windir%\iTunesMusic.exe.

    Note: %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows or C:\Winnt.

  2. Drops the file %System%\rdriv.sys, which is detected as Trojan.Cachecachekit. This file operates as a rootkit hiding the presence of the iTunesMusic.exe file and service.

  3. Creates the following registry subkeys to register itself as a service:


    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).

    The service has the following properties:

    Display Name: iTunesMusic
    Path to Executable: %Windir%\iTunesMusic.exe
    Description: W32.Spybot.NLX is executed at startup.

  4. Sets the value:

    "restrictanonymous" = "1"

    in the subkey:


    to modify access to network shares.

  5. Sets the value:

    "EnableDCOM" = "N"

    in the subkey:


    to disable DCOM.

  6. Creates the following registry subkeys:


  7. Modifies several registry subkeys to lower the Internet Explorer Security Zones settings.

  8. Attempts to disable the Windows XP Service Pack 2 Security Center and the Windows firewall by altering multiple registry subkeys.

  9. Adds the value:

    "DoNotAllowXPSP2" = "1"

    to the registry subkey:


    to prevent the installation of Windows XP Service Pack 2 on the compromised computer.

  10. Adds the value:

    "AUOptions" = "1"

    to the registry subkey:


    to prevent the installation of Windows XP Service Pack 2 on the compromised computer.

  11. Attempts to open a back door by connecting to the IRC channel on, through TCP port 4367.

  12. Listens for commands that allow the attacker to perform any of the following actions:

    • Download and execute files
    • List, stop, and start processes and threads
    • Launch ACK, SYN, UDP, and ICMP denial of service attacks
    • Perform port redirection
    • Send files over IRC
    • Send email using its own SMTP engine
    • Start a local HTTP, FTP, or TFTP server
    • Search for files on the compromised computer
    • Log keystrokes
    • Access network shares and copy itself to those network shares
    • Scan the network for vulnerable computers by means of port scanning
    • Capture screenshots, data from the clipboard, and footage from webcams
    • Visit URLs
    • Flush the DNS and ARP caches
    • Open a command shell on the compromised computer
    • Start a SOCKS4 proxy server
    • Add and delete network shares and disable DCOM
    • Reboot the compromised computer
    • Intercept packets on the local area network
    • Retrieve the currently logged on user's Windows password from memory
    • Send net send messages
    • Delete registry loading points from other programs and malware

  13. Scans for computers vulnerable to one or more of the following exploits:

  14. Attempts to propagate through back doors opened by variants of the Beagle, Sasser, and Mydoom worms, and by variants of Backdoor.NetDevil, Backdoor.Subseven, Backdoor.Kuang, and Backdoor.Optix.

  15. Attempts to steal the CD keys associated with a number of computer games.

  16. Attempts to spread to randomly generated IP addresses by copying itself to network shares. The worm attempts to use the following list of passwords to access the network shares:

    • 007
    • 123
    • 1234
    • 12345
    • 123456
    • 1234567
    • 12345678
    • 123456789
    • 1234567890
    • 2000
    • 2001
    • 2002
    • 2003
    • 2004
    • access
    • accounting
    • accounts
    • adm
    • administrador
    • administrat
    • administrateur
    • administrator
    • admins
    • asd
    • backup
    • bill
    • bitch
    • blank
    • bob
    • brian
    • changeme
    • chris
    • cisco
    • compaq
    • computer
    • control
    • data
    • database
    • databasepass
    • databasepassword
    • db1
    • db1234
    • db2
    • dba
    • dbpass
    • dbpassword
    • default
    • dell
    • demo
    • domain
    • domainpass
    • domainpassword
    • eric
    • exchange
    • fred
    • fuck
    • george
    • god
    • guest
    • hell
    • hello
    • home
    • homeuser
    • ian
    • ibm
    • internet
    • intranet
    • jen
    • joe
    • john
    • kate
    • katie
    • lan
    • lee
    • linux
    • loginpass
    • luke
    • mail
    • main
    • mary
    • mike
    • neil
    • nokia
    • none
    • null
    • oem
    • oeminstall
    • oemuser
    • office
    • oracle
    • orainstall
    • outlook
    • owner
    • pass
    • pass1234
    • passwd
    • password
    • password1
    • peter
    • pwd
    • qaz
    • qwe
    • qwerty
    • sam
    • server
    • sex
    • siemens
    • slut
    • sql
    • sqlpassoainstall
    • staff
    • student
    • sue
    • susan
    • teacher
    • technical
    • test
    • unix
    • web
    • win2000
    • win2k
    • win98
    • windows
    • winnt
    • winpass
    • winxp
    • www
    • wwwadmin
    • zxc


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

Discovered: April 12, 2005
Updated: February 13, 2007 1:03:54 PM
Also Known As: Backdoor.Win32.IRCBot.ao [Kasp, W32/Sdbot.worm.gen.i [McAfee], WORM_SDBOT.BKW [Trend Micro]
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.Spybot.NLX.
  4. Delete any values added to the registry.
  5. Restore the Windows Security Center
  6. Reset the Internet Security Zone Settings
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, reenable 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 document: 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 document: Virus Definitions (Intelligent Updater).

    The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

3. To scan for and delete the infected files
  1. The threat cannot be removed in Normal mode so start the computer in Safe Mode. For instructions on starting the computer in Safe mode, please read the document How to start the computer in Safe Mode.
  2. Run a full system scan.
  3. If any files are detected as infected with W32.Spybot.NLX, click Delete.

    After the files are deleted, restart the computer in Normal mode and proceed with section 4.

    Warning messages may be displayed when the computer is restarted, as the threat has not been fully removed at this point. Please ignore these messages and just click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

    Title: [File path]
    Message body: Windows cannot find [file name]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.

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. For instructions refer to the document: How to make a backup of the Windows registry.
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

  4. Navigate to the subkey:


  5. In the right pane, restore the original value if applicable:

    "EnableDCOM" = "Y"

  6. Navigate to the subkey:


  7. In the right pane, restore the original value if applicable:

    "restrictanonymous" = "0"

  8. Navigate to and delete the subkeys:


  9. Exit the Registry Editor.

5. To restore the Windows Security Center
This threat attempts to disable the features in the Windows Security Center, available in Windows XP Service Pack 2. If you are running Windows XP Service Pack 2 and would like to restore the full functionality of the Windows Security Center, please complete the following steps:

    Important: If your computer is connected to a domain, you may not be able to adjust these settings. If so, contact your network administrator for more information.
    1. Click Start > Control Panel.
    2. Double-click the Security Center.
    3. In the right pane, click Windows Firewall. The Windows Firewall appears.
    4. Select On.
    5. Click OK to close the Windows Firewall.
    6. In the left pane of the Security Center, select Change the way Security Center alerts me.
    7. Click Alert Settings.
    8. Select Alert Settings, Firewall, and Virus Protection.
    9. Click OK
    10. Click Automatic Updates.
    11. Select Automatic.
    12. Click OK.
    13. Exit the Security Center.
6. To reset the Internet Security Zone Settings
    1. Start Microsoft Internet Explorer.
    2. Click Tools > Internet Options.
    3. Click on the Security tab.
    4. Click on the Internet Icon on upper pane of the window.
    5. Click on Default Level on lower right corner of the window.
    6. Click on the Local Internet Icon on upper pane of the window.
    7. Click on Default Level on lower right corner of the window.
    8. Click on the Trusted sites Icon on upper pane of the window.
    9. Click on Default Level on lower right corner of the window.
    10. Click on the Restricted sites Icon on upper pane of the window.
    11. Click on Default Level on lower right corner of the window.
    12. Click OK on lower right corner of the window.

Writeup By: John Canavan