Backdoor.IRC.Flood.E

When Backdoor.IRC.Flood.E is executed, it will do the following:

1. Inserts the following files in the C:\Winnt\Inf folder:
   • Bootnt.dll: This file is not viral itself, and Norton AntiVirus will not detect it.
   • Mcop.dll: This is an IRC script.
   • Msvs32.bat: This is a batch file that will attempt to launch the IRC client over network shares.
   • Ntlib32.exe: This file is not viral itself, and Norton AntiVirus will not detect it.
   • Ntnwsys.ocx: This is an IRC script.
   • Ntzm32.dll: This is an IRC script.
   • Nwbt32.bat: This is a batch file that will attempt to remove certain shares from the system.
   • Pcc32.exe: This file is not viral itself, and Norton AntiVirus will not detect it.
   • Smc32.exe: This file is not viral itself, and Norton AntiVirus will not detect it.
   • Tskdbg.exe: This is an IRC client that will connect to a server on port 6667.
     
     
2. Adds the value:
   
   "taskdebug" = "C:\Winnt\Inf\tskdbg.exe"
   
   to the registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   so that the Trojan runs when you start Windows.

Once the files have been inserted on the system, Backdoor.IRC.Flood.E will attempt to perform the following actions:

1. Attempts to connect to an IRC server on port 6667. Once connected, it will await commands from the Trojan's creator.
   
   
2. Attempts to remotely launch Tskdgb.exe using network shares. The process will be launched by using the tool, Pcc32.exe.
   
   NOTE: Pcc32.exe is a legitimate tool called PsExec from sysinternals, and therefore, Norton AntiVirus will not detect the process.
   
   
3. Before the process is launched, the file, Tskdbg.exe, will be copied over to the remote computer.
   
   
4. The Backdoor will attempt the following username/password combinations to gain access on the remote machine.
   
   1. With the username "Administrator", it will try the following passwords.
      • [Blank]
      • Administrator
      • administrator
      • Admin
      • admin
      • changeme
      • abc
      • abc123
      • 123
      • 1234
      • 12345
      • 123456
      • 321
      • 4321
      • 54321
      • 654321
      • Pass
      • pass
      • Password
      • password
        
        The Backdoor Twill also attempt to connect as administrator without a password.
        
        
   2. With username "Admin", it will try the following passwords.
      • admin
      • 123
      • 1234
      • 12345
      • 123456
      • 321
      • 4321
      • 54321
      • 654321
        
        The Trojan will also attempt to connect as admin with password "admin."
        
        
   3. With username "Root," it will try the following passwords.
      • [Blank]
      • root
        
        
   4. Also attempts to connect using the followingusername/password combinations.
      • Student/Student
      • student/student
      • Teacher/Teacher
      • teacher/teacher
      • Test/Test
      • test/test
      • User/User
      • user/user
      • Guest/guest
        
        
5. Attempts to remove the following shares from the system (The shares will be removed using the batch file nwbt32.bat):
   • i$
   • j$
   • k$
   • l$
   • r$
   • ipc$
   • admin$
   • print$
   • g$
   • c$
   • m$
   • n$
   • o$
   • p$
   • h$
   • d$
   • e$
   • f$
   • s$
   • My Documents
   • Shared Docs
   • t$
   • u$
   • z$
   • v$
   • w$
   • x$
   • y$

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