W32.HLLC.Happylow

When W32.HLLC.Happylow runs, it copies itself as %windir%\Shine.exe.

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

The virus adds the value

Shine    %windir%\shine.exe /Trigger

to the registry key

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

so that the virus runs each time that you start Windows.

Next, it encrypts all .exe files that reside in the same folder as the virus and renames them with a .wal extension. It then makes a copy of itself as the original file name. The virus also uses the same method to infect %windir%\notepad.exe.

This method of infection is called companion. The virus simply renames the original file to a different extension and copies itself as the same name of the original file. For example, the virus encrypts Calc.exe and renames it to Calc.wal. Then the virus copies itself as Calc.exe, so that when the infected Calc.exe is executed, the virus execute its routine. Finally, it decrypts the Calc.wal file and executes it to make it appear as if Calc.exe has run normally.

The virus has a harmless payload. If the virus is executed with the /Trigger option or if the infected system is booted and the virus is running, the virus checks whether the following words are typed:

• sex
• help
• porn
• shine
• walrus
• finished
• help

If you type any of these words, then the virus payload is triggered. The payload displays a graphic of colorful happy flowers on the screen.

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