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Discovered: December 11, 2001
Updated: February 13, 2007 11:38:04 AM
Type: Trojan Horse

Backdoor.Optix is a backdoor Trojan program that was written in the Delphi language.

If a backdoor Trojan was successfully installed on the computer, it is possible that your system has been accessed remotely by an unauthorized user. For this reason it is impossible to guarantee the integrity of a system that has had such an infection. The remote user could have made changes to the system, including but not limited to the following:

  • Stealing or changing passwords or password files
  • Installing remote-connectivity host software, also known as backdoors
  • Installing keystroke logging software
  • Configuring firewall rules
  • Stealing credit card numbers, banking information, personal data, and so on
  • Deleting or modifying files
  • Sending inappropriate or even incriminating material from a customer's email account
  • Modifying access rights on user accounts or files
  • Deleting information from log files to hide such activities

To be certain that your organization is secure, you must reinstall the operating system, restore files from a backup that was made before the infection took place, and change all passwords that may have been on the infected computers or that were accessible from it. This is the only way to ensure that your systems are safe. For more information regarding security in your organization, contact your system administrator.

Antivirus Protection Dates

  • Initial Rapid Release version December 26, 2001
  • Latest Rapid Release version September 14, 2018 revision 021
  • Initial Daily Certified version December 26, 2001 revision 003
  • Latest Daily Certified version September 15, 2018 revision 002
  • Initial Weekly Certified release date December 26, 2002

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

Writeup By: Neal Hindocha

Discovered: December 11, 2001
Updated: February 13, 2007 11:38:04 AM
Type: Trojan Horse

Several variants of Backdoor.Optix have been discovered. All of them, when executed, open a port on the computer. This allows a hacker to connect to the computer and perform any desired actions. All variants discovered will also attempt to terminate the process for several antivirus and security products.

Some of the variants may execute additional files when the file containing Backdoor.Optix is executed. Variants that send messages using the ICQ network have also been discovered. The messages are sent to the author of the Trojan to tell them that an infected computer is online.

Many, but not all variants of Backdoor.Optix create a Winstart.bat file that can contain various commands. These commands could include recreating the Trojan if it is deleted.


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: Neal Hindocha

Discovered: December 11, 2001
Updated: February 13, 2007 11:38:04 AM
Type: Trojan Horse

Run LiveUpdate to make sure that you have the most recent virus definitions.

  1. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
  2. Run a full system scan.
  3. Delete all files that are detected as Backdoor.Optix. If any files are detected as Backdoor.Optix, delete the Winstart.bat file before you restart the computer. For detailed information, read the section that follows.

Delete the Winstart.bat file
This is necessary only if Backdoor.Optix was detected on your computer.

Most variants of Backdoor.Optix will create a batch file named Winstart.bat in the %Windows% folder. Winstart.bat is a standard Windows file that can be created and used by programs when you install software. If the Winstart.bat file exists, it will run when you start Windows, and any commands in it will be executed.

NOTE: %Windows% is a variable. The worm locates the \Windows folder (by default this is C:\Windows or C:\Winnt) and copies itself to that location.

Backdoor.Optix keeps a second copy of itself on the hard drive. It also may add commands to the Winstart.bat, so that if you delete the Trojan from its original location, when Winstart.bat is run, it will recreate the Trojan file. Norton AntiVirus does not detect the Winstart.bat file, because it is not by itself viral.

Therefore, if Backdoor.Optix is found on the computer, we strongly recommend that you use Windows Explorer to locate and delete the \Windows\Winstart.bat file before you restart the computer. To do this:
  1. Start Windows Explorer.
  2. Browse to the folder where Windows is installed. By default this is C:\Windows or C:\Winnt.
  3. Locate and delete the Winstart.bat file.

Writeup By: Neal Hindocha