Discovered: January 24, 2001
Updated: February 13, 2007 11:50:33 AM
Type: Trojan Horse


PHP.Sysbat is a Trojan horse, not a virus. Trojan horses do not replicate. PHP.Sysbat only executes on computers with PHP interpreters. (PHP is a server-side, cross-platform, HTML-embedded scripting language.) It cannot be contracted by simply visiting an infected Web page.

PHP.Sysbat modifies the Autoexec.bat file so that the next time the computer is restarted, the command to format the hard drive is executed. The Trojan will also append text to C:\Config.sys and to other files with the .sys extension that are located in the C:\Windows\Command folder. Finally, the Trojan tries to delete C:\Windows\System\Wsock32.dll.

Antivirus Protection Dates

  • Initial Rapid Release version January 25, 2001
  • Latest Rapid Release version August 08, 2016 revision 023
  • Initial Daily Certified version January 25, 2001
  • Latest Daily Certified version August 09, 2016 revision 001

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

Writeup By: Eric Chien

Discovered: January 24, 2001
Updated: February 13, 2007 11:50:33 AM
Type: Trojan Horse


When executed, the PHP.Sysbat Trojan does the following:

  1. It checks to see if the Config.sys file has been modified. If it has not been modified, the text

    47hGHRHjkliliurpIOIPOIporipOOPOirujkJKLLJj<Xmorfic>HKGJD
    Xmorfic, www.xxxxxxxx.com/xxxx, Second PHP VIRUS

    is added to the end of the file. (The x's represent a specific Web address).
  2. It checks to see if the Autoexec.bat file has been modified. If it has not been modified, the text

    ctty nul
    format c: /autotest /q /u

    is added to the Autoexec.bat file. This will format the drive C the next time the computer is restarted.
  3. It appends the following text to all .sys files that are located in the C:\Windows\Command folder:

    Xmorfic_VX_System_PHP_Infector!!
  4. It then attempts to delete the C:\Windows\System\Wsock32.dll file.
  5. Finally, the Trojan displays the text

    This program performed an illegal operation


Recommendations

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: Eric Chien

Discovered: January 24, 2001
Updated: February 13, 2007 11:50:33 AM
Type: Trojan Horse


To remove this Trojan:

  1. Run LiveUpdate to make sure that you have the most recent virus definitions.
  2. Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
  3. If any files are detected as infected by PHP.Sysbat, you need to delete them.
  4. Remove the following text from the Autoexec.bat file:

    ctty nul
    format c: /autotest /q /u

    CAUTION: Do not restart the computer until you have removed this text.
  5. Restore from backup or reinstall all .sys files that were infected by the Trojan.
  6. Replace the Wsock32.dll file, if necessary.


Writeup By: Eric Chien