Discovered: March 27, 2000
Updated: February 13, 2007 11:34:26 AM
Also Known As: WYX.b
Type: Virus
Systems Affected: Windows


This is an encrypted boot virus, capable of infecting the Master Boot Record and the Boot Sector of hard disks on target computers. It is not destructive.

Antivirus Protection Dates

  • Initial Rapid Release version March 27, 2000
  • Latest Rapid Release version March 27, 2000
  • Initial Daily Certified version March 27, 2000
  • Latest Daily Certified version March 27, 2000
  • Initial Weekly Certified release date March 27, 2000

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


Technical Description


Some systems using boot managers or multiple-OS systems that store information in the first track of the hard disk might be irreparable.

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.


Removal


To repair this virus:

  1. Run LiveUpdate to make sure that you have the most recent virus definitions.
  2. Close all programs, shut down the computer, turn off the power, and wait thirty seconds. You must do this to clear memory.
  3. Do one of the following, depending on your version of Norton AntiVirus (NAV):
    • NAV 2002. Follow these steps to run the DOS scanner:
      1. Restart the computer using a clean DOS boot disk that you created on an uninfected computer.
      2. Run Navdx.exe (the DOS scanner) from the from the Norton AntiVirus program folder using the /boot and /repair switches. For example:

        C:> \progra~1\norton~1\navdx.exe /cfg:a /boot /repair
      3. Press Enter and follow the prompts if any.
    • NAV 2001. Follow these steps to run the DOS scanner:
      1. Restart the computer using a clean DOS boot disk or a NAV 2001 Emergency Disk that you created on an uninfected computer.
      2. Run Navdx.exe (the DOS scanner):
        • If you are using a boot disk, run it from the from the Norton AntiVirus program folder using the /boot and /repair switches. For example:

          C:> \progra~1\norton~1\navdx.exe /cfg:a /boot /repair

        • If using the NAV 2001 Emergency Disk, type the following at the Emergency Disk command line:

          navdx.exe /cfg:a /boot /repair
      3. Press Enter and follow the prompts if any.
    • NAV 2000 and earlier. Versions of the Emergency Disk program that are included in NAV 2000 and earlier may not be able to remove this virus. You need to download the free, updated version of the DOS scanner. See the document How to create Emergency Disks by downloading a program from the Symantec FTP site.

      After you have created the Emergency Disks on an uninfected computer, follow these steps to run the DOS scanner:
      1. Restart the computer using the Emergency Disk.
      2. At the Emergency Disk command line, type:

        navdx.exe /cfg:a /boot /repair
      3. Press Enter, and follow the prompts.


Writeup By: Jimmy Shah