W32.Tzet.Worm

1. Inserts the following files in the System% folder:
   • Authexec.bat
   • Iglmtray.exe
   • Iglxtray.exe
   • Lrss.ini
   • Mdde32.exe
   • Net.bat
   • Nna.exe
   • Printf_core.exe
   • Vidriv.exe
   • Wmpt.exe
   • Wsubsys.wav
   • Xcopy.dll
     
     NOTE: Other file names are possible.
     
     
2. Creates the value:
   
   "WUPD"="%system%\iglmtray.exe"
   
   under the registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   
3. Attempts to infect a random system on the Internet (attacking weak administrator or default account passwords), by using a batch file and a utility from Sysinternals, which W32.Tzet.Worm uses to copy itself to and execute on that system.
   
   The accounts that are attacked are:
   
   admin
   Administrador
   Administrateur
   Administrator
   cs
   database
   guest
   network
   root
   sql
   sqladmin
   sqlagent
   student
   teacher
   test
   user
   wwwadmin
   wwwroot
   
   The passwords that it attempts to use include, among others:
   
   <no password>
   123[4][5][6],
   <account name>
   password.
   
   Note: Due to the way the worm attacks remote computers, the spreading cababilities of this worm will not work against or on Windows 95/98/Me systems.
   
   
4. Logs into IRC and announces its presence to the creator(s) of the worm. The IRC connection is attempted on the following servers:
   
   lms.tmclan.net:7648
   rms.tmclan.net:7648
   cms.tmclan.net:7648
   
   Once a connection is established, the worm will log into an IRC channel, where the attacker can now remotely control it. The current version logs by default into the channel #º-scan-º# with the password !(sc4n)!.

• Remote control (backdoor capability)
• Re-routing HTTP network traffic through the host computer
• Stealing key information of various popular games
• Launching a Denial of Service (DoS) attack against a single computer

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.