Backdoor.OptixPro.13b

Backdoor.OptixPro.13b is a minor variant of Backdoor.OptixPro.13, with additional features designed to complicate detection and removal.

Backdoor.OptixPro.13b can be configured to perform any or all of the following actions:

Files
Backdoor.OptixPro.13b copies itself to either the %Windir% or %System% folder as <name of original Trojan file> and <name of shell hook file>. This action varies and depends on the configuration settings in the Trojan.

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Note:

• %Windir% is a variable: The Trojan locates the Windows installation folder (by default, this is C:\Windows or C:\Winnt) and copies itself to that location.
• %System% is a variable: The Trojan locates the System folder and copies itself to that location. By default, this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
• <name of original Trojan file> represents the file name of the Trojan. The attacker selects this.
• <name of shell hook file> represents the file name of the Trojan when handling the execution of the .exe files. The attacker also selects this.

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Registry autostart

Backdoor.OptixPro.13b creates a string value under the registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices

so that Backdoor.OptixPro.13b is executed each time you start Windows.

This registry value is of the form:

"<registry value name>"="<path to trojan file>"

The attacker chooses the <registry value name>.

Registry shell hook
Backdoor.OptixPro.13b hooks the execution of the executable files, by changing the (Default) value of the registry key:

HKEY_CLASSES_ROOT\exefile\shell\open\command

to:

<path to shell hook file as>


Registry RAS settings
Backdoor.OptixPro.13b modifies the behavior of the computer when connected to a modem, by changing the registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles\Current\Software\Microsoft\Windows\CurrentVersion\Internet Settings\EnableAutoDial

to:

0

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Internet Settings\EnableAutoDial

to:

0

HKEY_LOCAL_MACHINE\Software\Microsoft\RAS Autodial\Control\DisableConnectionQuery

to:

1

HKEY_LOCAL_MACHINE\Software\Microsoft\RAS Autodial\Control\LoginSessionDisable

to:

1


System files
Backdoor.OptixPro.13b modifies the Run= line of the Win.ini file to:

Run=<path to trojan file>

as well as the Shell= line of the System.ini file to:

Shell=Explorer.exe <path to trojan file>


Ports
Backdoor.OptixPro.13b opens a listening port on port 3410. (This is the default port, but the attacker can configure the Backdoor Trojan to any other port.)


Functionality
Backdoor.OptixPro.13b allows the attacker to do the following:


Evasion options

• Hide files from the user
• Hide registry keys from the user
  
  

Notification options
An attacker can be notified that the backdoor has been installed by a number of different methods.

• SMTP email
• HTTP request
• Instant messaging notification (IRC, MSN, or ICQ)
  
  

Power options

• Log off the current user
• Restart the system
• Shut down the system
• Suspend the system
• Crash the system, causing a blue screen to appear

Backdoor information
Obtain information about the running Trojan


File system

• Upload and download files
• Execute files
• Create folders
• Delete files and folders
• Rename files and folders

Processes

• List running processes
• Stop running process

Windows tasks

• Minimize windows
• Maximize windows
• Change the title of windows
• Close windows
• Send keystrokes to specific windows

Registry

• Create new values and keys
• Edit values
• Delete values and keys

FTP server
Launch an FTP server on a specified port.


IP scanner
Launch a <IP range>:port scan from a compromised system for the open ports.


Port redirection
Redirect connections to a compromised system on a specific port to another computer and port.


System information

• Acquire system information, such as the owner, OS version, and key and CPU type and speed
• Steal cached passwords
• Steal AIM passwords
• Steal RAS passwords

System monitoring

• Provide a live feed of the system screen
• Provide a live feed through the system Webcam
• Launch a keylogger

Other

• Open and close the CD-ROM drive
• Show and hide the clock
• Turn the monitor on and off
• Start and stop the screensaver
• Enable and disable the mouse and keyboard
• Produce beeping sounds from the computer's speaker

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.

Summary