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K2PS.EXE Trojan

K2PS.EXE Trojan

12 May 1999
13 February 2007
Also Known As:
Trojan Horse, TX-500

K2PS.EXE is a Trojan Horse that was distributed as an email attachment with the filename of "K2PS.EXE" to users of Fujitsu's InfoWeb Internet account users in Japan.

1) K2PS.EXE is a 32-bit Windows executable and designed to work under Windows 95/98. It will not work under Windows NT because of specific API it uses to retrieve the password information.

2) When the file is executed, it will copy itself to the "WINDOWS\SYSTEM" directory.

3) The following registry key will be modified to execute K2PS.EXE program automatically every time Windows is launched: \\HKEY_LOCAL_MACHINE\Software\Microsoft\Window\CurrentVersion\Run

4) When Windows is re-launched, the K2PS.EXE program will automatically execute and a hidden file called K2PS.CFG will be created in the \WINDOWS\SYSTEM directory.

5) If you are connected to the Internet, the trojan will automatically connect to an email server in Brazil and try to send the dialup information from the computer including login name and password. It is not possible to see this script with in the executable since it has been encrypted with a simple "ROR" algorithm.

6) The information is sent to a "free mail" email user account in Japan with the email address of "", so it is difficult to trace the owner of the email account.

Antivirus Protection Dates

  • Initial Rapid Release version 20 December 2000
  • Latest Rapid Release version 20 August 2008 revision 017
  • Initial Daily Certified version 20 December 2000
  • Latest Daily Certified version 20 August 2008 revision 016
  • Initial Weekly Certified release date pending
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

The email stated that a new virus called TX-500 has recently been discovered and the attachment was an antivirus program to eradicate the TX-500 virus and users should execute this on their systems. The attachment was not an antivirus program of any sort. K2PS.EXE was a malicious Trojan Horse program designed to steal your dial up network password information and secretly send them to an email account in Japan. Once the creator of this trojan has received this information, it is possible to take over the users Internet account, access the users email, run up the Internet access bill and even change the password to the Internet account. If you received this file and have executed this file, it is important to change all your passwords on your dialup network accounts.


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.

If you have not executed K2PS.EXE, simply delete the file. If you have executed the file, follow the following steps to clean up your system.

1) Delete K2PS.EXE

2) Delete K2PS.EXE from \WINDOWS\SYSTEM directory.

3) Delete a hidden file called K2PS.CFG from \WINDOWS\SYSTEM directory. You will have to change the "hidden" attribute to delete the file by using a command such as "attrib -hr k2ps.cfg".

4) Use regedit.exe and delete the following registry key: HKEY_LOCAL_MACHINE\Software\Microsoft\Window\CurrentVersion\Run\K2ps.tasks C:\WINDOWS\SYSTEM\K2PS.EXE

5) Lastly and most importantly, change your password for all of the dialup network accounts you have registered on your computer. If you do not know how to change your password for the dialup network accounts, you should contact the support center of your Internet provider.

Norton AntiVirus users can protect themselves from this trojan by downloading the current virus definitions either through LiveUpdate of from the following web page:

Writeup By: Motoaki Yamamura