Backdoor.Laphex.Client

Backdoor.Laphex.Client makes it possible to control a computer that is infected with the Backdoor.Laphex server component.

This client program contains the following features:

• It allows its user to define the server address and port on which the client looks for a running Backdoor.Laphex server (the compromised computer).
• It can upload a file to the Windows folder (the location in which the server is installed) of the compromised computer.
• It can download URLs and files from the compromised computer.

This client program can create a small server component, and its user can either use its default values or configure the following values (the program's default values are shown in brackets):

• The file name for the new dropped server component [Institution.exe]
• The port on which it listens [5152].
• The ICQ number for notifications. []
• The Password for the server [Aphex!].

This dropped server component name is Server.exe, and its size is 3,584 bytes. It is detected as Backdoor.Laphex.

When you open the Backdoor.Laphex.Client program, you see this message:

Legal Agreement

Institution is written for personal use only. Institution is provided "AS IS". The author makes no representations or warranties, expressed or implied, including but not limited to, warranties of merchantablity or fitness for any particular purpose. The author of Institution will in no way be held responsible for any damages caused by the negligent use of this software. Once you agree you will be bound to these terms as long as you use this software.
Do you agree to these terms of use?

If you click Yes, Backdoor.Laphex.Client adds the value

institutionlegal 0x00000000 (0)

to the registry key

HKEY_LOCAL_MACHINE\SOFTWARE

This value is later used to check whether the client user has agreed the terms of the Backdoor.Laphex.Client program. If it does not find this value, it displays the message again.

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