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Discovered: July 01, 2002
Updated: February 13, 2007 11:57:29 AM
Also Known As: TROJ_DOAL.A, Win32/DlToon [Computer Associa
Type: Trojan Horse
Systems Affected: Windows

This Trojan Horse resembles W32.Whiter.Trojan in that it may pose as a "key generator" for Windows XP. This Trojan is not a "key generator" and may delete files on the local hard drive if it is run.

The most common way that this Trojan is spread is through the use of file-sharing clients such as Kazaa or Morpheus. The filename of this Trojan is
"Windows XP Home Edition Keygen.exe," but the name could be easily changed to something else.

The Trojan's icon looks like:

Antivirus Protection Dates

  • Initial Rapid Release version July 02, 2002
  • Latest Rapid Release version September 28, 2010 revision 054
  • Initial Daily Certified version July 02, 2002
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date July 03, 2002

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

Writeup By: Patrick Nolan

Discovered: July 01, 2002
Updated: February 13, 2007 11:57:29 AM
Also Known As: TROJ_DOAL.A, Win32/DlToon [Computer Associa
Type: Trojan Horse
Systems Affected: Windows

This Trojan was packaged within a software installation program named "Vise."

If this Trojan is run, it does the following:

  1. Creates these folders:
    • C:\Program Files\Windows XP Home Keys
    • C:\Program Files\Common Files\Software

  2. Creates these files:
    • C:\Program Files\Windows XP Home Keys\Windows XP Home Edition Serials.diz (499 Bytes). (This is a text file containing several ASCII strings that resemble the format of Windows registration serial numbers.)
    • C:\Program Files\Common Files\Software\Load.exe (312,606 Bytes)

  3. So that the Trojan runs when you start Windows, it adds the value:

    Microsoft Tasks      C:\Program Files\Common Files\Software\Load.exe

    to the registry key:


    The next time that the computer is restarted, Load.exe will run and delete the key system files, such as Win.com, Autoexec.bat, and numerous .dll files in the Windows\System folder.


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: Patrick Nolan

Discovered: July 01, 2002
Updated: February 13, 2007 11:57:29 AM
Also Known As: TROJ_DOAL.A, Win32/DlToon [Computer Associa
Type: Trojan Horse
Systems Affected: Windows

  1. Update the virus definitions
  2. Run a full system scan and delete all the files that Norton AntiVirus detects as W32.Doal.Trojan.
  3. Remove the value from the Registry: Microsoft Tasks

    from the registry key:

For specific details on how to do this, read the following instructions.

1. Updating 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.

2. Scanning for and deleting 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. Delete all the files that Norton AntiVirus detects as W32.Doal.Trojan. Replace the deleted files from a clean backup or re-install them.

3. Removing the value from the registry

CAUTION : 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, and then click OK. (The Registry Editor opens.)
  3. Navigate to the following key:


  4. In the right pane, delete the following value:

    Microsoft Tasks

  5. Click Registry, and then click Exit.

Writeup By: Patrick Nolan