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Discovered: March 12, 2003
Updated: February 13, 2007 11:44:20 AM
Type: Trojan Horse
Systems Affected: Windows

Hacktool.PWS.QQPass is a Trojan creation tool. The Trojans created with this tool can be programmed to steal dial-up networking telephone numbers and passwords, as well as the passwords of OICQ, which is a popular Chinese chat program. The filename of the file detected as Hacktool.PWS.QQPass consists of five random letters with the .exe extension.

Then, the Trojan sends this information to a specified set of email addresses.

Antivirus Protection Dates

  • Initial Rapid Release version March 13, 2003
  • Latest Rapid Release version November 16, 2018 revision 021
  • Initial Daily Certified version March 13, 2003 revision 002
  • Latest Daily Certified version November 17, 2018 revision 002
  • Initial Weekly Certified release date March 19, 2003

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

Writeup By: Yana Liu

Discovered: March 12, 2003
Updated: February 13, 2007 11:44:20 AM
Type: Trojan Horse
Systems Affected: Windows

Hacktool.PWS.QQPass can be used to create the server part of a backdoor Trojan. The Trojan that it creates is approximately 46 K in length and is compressed using ASPack. The created Trojan runs on Windows 95/98/Me systems only, and it may be detected as Backdoor.Trojan.

When the Trojan that Hacktool.PWS.QQPass created is run, it does the following:

  1. Copies itself to the Windows installation folder and Windows system folder, using randomly generated filenames. The filename has five random letters as the name and .exe as the extension.
  2. Adds the value:

    msgserv_ %System%\<the Trojan file>

    to the registry key:


    so that the Trojan runs when you start Windows.
  3. Adds the values:

    system_ %System%\<the Trojan file>
    userfile_ %System%\<*.dll>
    windows32_ <the Trojan file>

    to the registry key:


    For example, if the Trojan file is Moqsu.exe.exe, the .dll filename will be Moqsu.dll. The Trojan uses this .dll file to store the stolen information.
  4. Inserts the following line in the [boot] section of the System.ini file:

    shell=explorer.exe %System%\<the Trojan file>

    so that the Trojan runs when you start Windows.
  5. Registers its process as a service. Because it uses the RegisterServiceProcess API, the Trojan can only run under Windows 98. The Hacktool itself can run on all Windows-based operating systems.
  6. Steals information from your computer and sends the information to a predefined email address. The stolen information includes:
    • Dial-up networking telephone numbers
    • User name and passwords
    • OICQ UID number and password


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: Yana Liu

Discovered: March 12, 2003
Updated: February 13, 2007 11:44:20 AM
Type: Trojan Horse
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. Update the virus definitions.
  2. Run a full system scan and delete all the files detected as Hacktool.PWS.QQPass or Backdoor.Trojan.
  3. Delete the value that was added to the registry.
  4. Remove the text that was added to the System.ini file.

For specific details on each of these steps, 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 here. For detailed instructions on how to download and install the Intelligent Updater virus definitions from the Symantec Security Response Web site, click here.

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. If any files are detected as infected with Hacktool.PWS.QQPass or Backdoor.Trojan, click Delete.

3. Deleting the value from the registry

CAUTION : Symantec strongly recommends that you back up the registry before you make 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:

    msgserv_ %System%\<the Trojan file>
  5. Exit the Registry Editor.

4. Removing the text from the System.ini file
  1. The function you perform depends on your operating system:
    • Windows 95/98: Go to step b.
    • Windows Me: If you are running Windows Me, the Windows Me file-protection process may have made a backup copy of the System.ini file that you need to edit. If this backup copy exists, it will be in the C:\Windows\Recent folder. Symantec recommends that you delete this file before continuing with the steps in this section. To do this:
      1. Start Windows Explorer.
      2. Browse to and select the C:\Windows\Recent folder.
      3. In the right pane, select the System.ini file and delete it. The System.ini file will be regenerated when you save your changes to it in step f.
  2. Click Start, and then click Run.
  3. Type the following:

    edit c:\windows\system.ini

    and then click OK. (The MS-DOS Editor opens.)

    NOTE: If Windows is installed in a different location, make the appropriate path substitution.
  4. In the [boot] section of the file, look for a line similar to:

    shell = Explorer.exe %System%\<the Trojan file>
  5. If this line exists, delete everything to the right of Explorer.exe.

    When you are done, it should look like:

    shell = Explorer.exe
  6. Click File, and then click Save.
  7. Click File, and then click Exit.

Writeup By: Yana Liu