W32.Kwbot.B.Worm

When the W32.Kwbot.B.Worm runs, it does the following:

1. Copies itself as C:\%System%\MSInstall61.exe.
   
   NOTE: %System% is a variable. The worm locates the Windows System folder and copies itself to that particular location. By default, the location is C:\Windows\System (Windows 95/98/Me), C:\Windows\System32 (Windows XP), or C:\Winnt\System32 (Windows NT/2000).
   
2. Adds the value
   
   Internet Loader1  C:\%SYSTEM%\MSInstall61.exe
   
   to the following registry keys:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
   CurrentVersion\RunServices
   HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
   HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\
   CurrentVersion\RunServices
   
   This causes the worm to run when you start Windows.
   
3. Opens a randomly chosen TCP/UDP port to connect to the hacker.
   
4. Copies itself to the default KaZaA shared folder using many different names randomly chosen from a list that the worm carries. Some examples are:
   • Howtouseashell.exe
   • Visio.exe
   • Worldbook.exe
   • HotGirls.exe
   • Linux.exe
   • Gta3.exe
   • Driver.exe
   • Hack_aim.exe
   • How_to_hack.exe
   • Divx_pro.exe
   • Pamela_anderson.scr
   • Wc3_keygen.exe
   • Hotmail_hack.exe

NOTE: The W32.Kwbot.B.Worm requires that the KaZaA software be installed on the computer for it to spread.

The W32.Kwbot.B.Worm contains its own Internet Relay Chat (IRC) client, allowing the worm to connect to an IRC channel, which was coded into the Trojan. Using the IRC channel, the Trojan listens for commands from the hacker. The commands allow the hacker to perform any of the following actions:

• Manage the installation of the backdoor.
• Control the IRC client on the compromised computer.
• Dynamically update the installed Trojan.
• Send the Trojan to other IRC channels to attempt to compromise more computers.
• Download and execute files.
• Deliver system and network information to the hacker.
• Perform Denial of Service (DoS) attacks against a target defined by the hacker.
• Completely uninstall itself by removing the relevant registry entries.

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