Backdoor.Haxdoor.D

1. Create the following files:
   
   • %System%\w32tm.exe
   • %System%\drct16.dll
   • %System%\cz.dll
   • %System%\vdmt16.sys
   • %System%\hz.dll
   • %System%\winlow.sys
   • %System%\wz.dll
   • %System%\p2.ini
     
     Notes:
   • %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
   • Some of the above files and registry key entries may not be visible under normal Windows restart since the Trojan hides files from showing up in Windows Explorer.
     
     
2. Runs %System%\w32tm.exe as a hidden process and will not be visible from Task Manager.
   
   
3. Adds the value:
   
   "Secboot" = "w32tm.exe"
   
   to the following registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
   
   so that it is executed every time Windows starts.
   
   
4. Creates the following registry keys:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\vdmt16
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ENUM\ROOT\LEGACY_VDMT16
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\memlow
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ENUM\ROOT\LEGACY_MEMLOW
   
   
5. Adds the value:
   
   "Disable TrayIcon" = "1"
   
   to the following registry key:
   
   HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
   
   in an attempt to disable the kernel from checking for abnormal memory overwrites and allows the Trojan to overwrite parts of the memory.
   
   
6. Adds the values:
   
   "StackSize" = "21:10"
   "Impersonate" = "[TIMESTAMP]"
   
   to the following registry key:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
   
   in an attempt to disable the kernel from checking for abnormal memory overwrites and allows the Trojan to overwrite parts of the memory.
   
   
7. Adds the value:
   
   "hws" = "[0xRandom]"
   
   to the following registry key:
   
   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion
   
   in an attempt to disable the kernel from checking for abnormal memory overwrites and allows the Trojan to overwrite parts of the memory.
   
   
8. Adds the values:
   
   "EnforceWriteProtect" = "0"
   
   to the following registry key:
   
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Session Manager\Memory Management
   
   in an attempt to disable the kernel from checking for abnormal memory overwrites and allows the Trojan to overwrite parts of the memory.
   
   
9. Modifies the values on Windows 95/98/Me computers:
   
   "DllName" = "draw32.dll"
   "EntryPoint" = "MedManager"
   "StackSize" = "0"
   
   to the following registry key:
   
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\MPRServices\
   TestService
   
   
10. Modifies the values on Windows 2000/NT/XP computers:
    
    "DllName" = "drct16.dll"
    "Startup" = "MedManager"
    "Impersonate" = "dword:00000001"
    "Asynchronous" = "dword:00000001"
    "MaxWait" = "dword:00000001"
    
    to the following registry key:
    
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\drct16
    
    
11. Opens the following TCP ports 16661, and two additional high random ports and waits for commands from a remote attacker. On connection it responds with the message "A-311 Death welcome".
    
    
12. Attempts to make a copy of the system password file SAM as a file called SLL. It also logs key strokes that match certain keywords.
    
    
13. Sends out an email to the remote attacker containing the information stolen from the compromised system.

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.