W32.Versie.A

Once executed, the worm copies itself as the following files:

• %ProgramFiles%\Common Files\Microsoft Shared\MSInfo\_[RANDOM NAME1].exe
• %System%\[RANDOM NAME1].exe

It copies itself to the root of fixed and removable drives as the following files:

• [DRIVE LETTER]:\[RANDOM NAME1].exe
• [DRIVE LETTER]:\Autorun.inf

The worm creates the following files:

• %ProgramFiles%\Common Files\Microsoft Shared\MSInfo\Paramstr.txt (log files)
• %System%\RelDelBat.Bat

It creates a service with the following characteristics:

• Service name: LocalSystem
• Display name: Windows Rnljm MingZai
• Description: Foundation network connection
• Image Path: %System%\rnljm.exe
• Startup Type: Automatic

It registers itself to run as a service by creating the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Windows [RANDOM NAME1] [RANDOM NAME2]

The worm sets the following registry key to enable autorun on mapped drives:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\"NoDriveTypeAutoRun" = "0"

It disables Start Page protection for Internet Explorer by setting the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Control Panel\"Homepage" = "1"

The worm modifies the following registry subkey to change the Internet Explorer Start Page:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\Start Page

It also modifies the following registry entries to change the user's desktop wallpaper:
HKEY_CURRENT_USER\Control Panel\Desktop\"TileWallpaper" = "0"
HKEY_CURRENT_USER\Control Panel\Desktop\"Wallpaper" = "[PATH TO DOWNLOADED WALLPAPER]"

It modifies the following registry entry to disable the Windows Remote Assistance facility:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\"fDenyTSConections" = "0"

The worm launches the following two processes then injects itself into the memory space of these processes masquerading as legitimate processes:

• iexplore.exe
• svchost.exe

The worm checks for the presence of %System%\drivers\klick.sys and if found, sets the date to 1981 and pings 127.0.0.1.

The worm opens a back door on the compromised computer that connects to jackie.crwoo.com on TCP port 1986 and awaits further commands that allows a remote attacker to perform some of following actions:

• Log keystrokes typed
• Download and execute additional files
• Shut down the compromised computer

The worm may download the following file:
%ProgramFiles%\Common Files\Microsoft Shared\MSInfo\Beizhu.txt (log files)

It creates custom Internet Favorites by dropping URL links in the following folder:
%UserProfile%\Favourites

The worm disables encryption for Tencent Messenger by deleting the file npkcrypt.sys from the application installation folder.

Note: The default installation folder is usually C:\Program Files\Tencent\QQ\.

The worm sends the following system information to the remote attacker:

• CPU speed
• Memory available
• OS version
• Service Packs installed

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