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Discovered: February 24, 2009
Updated: February 25, 2009 6:21:40 AM
Also Known As: W32/AutoIt-GY [Sophos]
Infection Length: Varies
Systems Affected: Windows

W32.Spamuzle.E is a Trojan horse that sends spam email, downloads potentially malicious files and steals information from the compromised computer.

Antivirus Protection Dates

  • Initial Rapid Release version February 24, 2009 revision 002
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version February 24, 2009 revision 024
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date February 25, 2009

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

Writeup By: Kaoru Hayashi

Discovered: February 24, 2009
Updated: February 25, 2009 6:21:40 AM
Also Known As: W32/AutoIt-GY [Sophos]
Infection Length: Varies
Systems Affected: Windows

When the Trojan executes, it infects the following files:

  • %Windir%\explorer.exe
  • %System%\dllcache\explorer.exe

Note: The above files are detected as W32.Spamuzle.E!inf .

The infected explorer.exe files drop the following file when executed:

Note: Multiple files with random file names will be created.

The Trojan then creates a backup copy of %System%\sfc_os.dll in the following location:

It then deletes the following files:
  • %System%\dllcache\sfc.dll
  • %System%\dllcache\sfc_os.dll

It then modifies the following files:
  • %System%\drivers\tcpip.sys
  • %System%\sfc_os.dll

The Trojan then creates the following registry entry so that it runs whenever Windows starts:

It also creates the following registry subkey:

The Trojan then modifies the following registry entries to alter Windows System File Checker settings:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"SFCDisable" = "ffffff9d"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"SFCScan" = "0"

The Trojan also modifies the following registry entry:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"PrivDiscUiShown" = "1"

The Trojan then attempts to end the following process:

The Trojan has rootkit capabilities that enable it to hide its presence.

Next, the Trojan deletes the following DNS cache entries:

The Trojan may then perform the following actions on the compromised computer:
  • Gather email addresses in order to send spam
  • Download files
  • Check for the presence of certain software by searching the registry

The Trojan sends the gathered information to a remote server by connecting to the following URL:

Writeup By: Kaoru Hayashi

Discovered: February 24, 2009
Updated: February 25, 2009 6:21:40 AM
Also Known As: W32/AutoIt-GY [Sophos]
Infection Length: Varies
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.
  4. Delete any values added to the registry.
  5. Extract and restore Windows files.

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, 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.

    If you use Norton AntiVirus 2006, Symantec AntiVirus Corporate Edition 10.0, or newer products, LiveUpdate definitions are updated daily. These products include newer technology.

    If you use Norton AntiVirus 2005, Symantec AntiVirus Corporate Edition 9.0, or earlier products, LiveUpdate definitions are updated weekly. The exception is major outbreaks, when definitions are updated more often.

  • 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.

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 run a full system scan
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.

    For Norton AntiVirus consumer products: Read the document: How to configure Norton AntiVirus to scan all files.

    For Symantec AntiVirus Enterprise products: Read the document: How to verify that a Symantec Corporate antivirus product is set to scan all files.

  2. Run a full system scan.
  3. If any files are detected, follow the instructions displayed by your antivirus program.
Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do 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 the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and 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.

    Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.

  4. Navigate to and delete the following registry entry:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Command Processor\"RunOnce" = "[RANDOM CHARACTERS]"

  5. Navigate to and delete the following registry subkey:


  6. Restore the following registry entries to their previous values, if required:

    • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"SFCDisable" = "ffffff9d"
    • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"SFCScan" = "0"
    • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"PrivDiscUiShown" = "1"

  7. Exit the Registry Editor.

    Note: If the risk creates or modifies registry subkeys or entries under HKEY_CURRENT_USER, it is possible that it created them for every user on the compromised computer. To ensure that all registry subkeys or entries are removed or restored, log on using each user account and check for any HKEY_CURRENT_USER items listed above.
5. To extract and restore Windows files
The following documents provide general instructions on how to extract files. This information is provided for your convenience. The exact steps may vary slightly depending on the configuration of your operation system, the location of the files, and so on. For additional information, read the Help files, contact Microsoft, or refer to the following Windows documentation:

Writeup By: Kaoru Hayashi