Trojan.Hiween

Risk Level 1: Very Low

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Discovered: September 7, 2006
Updated: February 13, 2007 12:58:48 PM
Type: Trojan Horse
Systems Affected: Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP



When Trojan.Hiween is executed, it performs the following actions:

  1. Copies itself as the following files:

    • C:\mig2.exe
    • C:\mig2\New Folder.exe
    • C:\Untukmu.txt
    • C:\mig2\Folder.htt
    • C:\Data [USERNAME].exe
    • %Windir%\mig2.exe
    • %System%\shell.exe
    • %System%\MrHelloween.scr
    • %System%\IExplorer.exe
    • %CurrentFolder%\Data [USERNAME].exe
    • C:\Document and Settings\All Users\Start Menu\Programs\Startup\Empty.pif
    • C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\WINLOGON.EXE
    • C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\CSRSS.EXE
    • C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\SERVICES.EXE
    • C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\LSASS.EXE
    • C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\SMSS.EXE
    • C:\Document and Settings\All Users\Start Menu\Programs\Startup\Startup.exe
    • C:\Document and Settings\All Users\My Documents\My Documents.exe
    • C:\Document and Settings\All Users\Desktop\Desktop.exe
    • C:\WINDOWS\System32\config\systemprofile\Start Menu\Programs\Startup\Startup.exe
    • C:\WINDOWS\System32\config\systemprofile\My Documents\My Documents.exe
    • C:\WINDOWS\System32\config\systemprofile\Desktop\Desktop.exe

      Note:
    • %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows (Windows 95/98/Me/XP) or C:\Winnt (Windows NT/2000).
    • %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).
    • %CurrentFolder% is a variable that refers to the folder where the risk was originally executed.

  2. Creates the following file:

    C:\Untukmu.txt

  3. Adds the values:

    "mig2" = "%Windir%\mig2.exe"
    "MSMSGS" = "C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\WINLOGON.EXE"
    "Services[USERNAME]" = "C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\SERVICES.EXE"
    "Logon[USERNAME]" = "C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\CSRSS.EXE"
    "System Monitoring" = "C:\Document and Settings\[USERNAME]\Local Settings\Application Data\WINDOWS\LSASS"

    to the registry subkey:

    HKEY_USERS\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    so that it runs every time Windows starts.

  4. Adds the value:

    "AlternateShell" = "%Windir%\mig2.exe"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot

    so that it runs every time Windows starts.

  5. Adds the value:

    "SCRNSAVE.EXE" = "C:\WINDOWS\System32\MRHELL~1.SCR"

    to the registry subkey:

    HKEY_CURRENT_USER\Control Panel\Desktop

    so that it runs every time certain programs are executed.

  6. Adds the value:

    "AlternateShell" = "%Windir%\mig2.exe"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot

    so that it runs every time certain programs are executed.

  7. Adds the values:

    "Userinit" = "%System%userinit.exe,%System%\IExplorer.exe"
    "Shell" = "Explorer.exe "%System%\IExplorer.exe""


    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\Windows NT\CurrentVersion\Winlogon

    so that it runs every time certain programs are executed.

  8. Adds the value:

    "Debugger" = "%System%\Shell.exe"

    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug

    so that it runs every time certain programs are executed.

  9. Adds the value:

    "(Default)" = ""%System%\shell.exe" "%1" %*"

    to the registry subkeys:

    HKEY_CLASSES_ROOT\batfile\shell\open\command
    HKEY_CLASSES_ROOT\piffile\shell\open\command
    HKEY_CLASSES_ROOT\exefile\shell\open\command
    HKEY_CLASSES_ROOT\lnkfile\shell\open\command

    HKEY_CLASSES_ROOT\comfile\shell\open\command

    so that it runs every time certain programs are executed.

  10. Adds the values:

    "DisableCMD" = "1"
    "DisableTaskMgr" = "1"
    "DiableRegistryTools" = "1"
    "DisableTaskMgr" = "1"


    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System

    to limit the user's privileges.

  11. Adds the value:

    "NoFolderOptions" = "1"

    to the registry subkeys:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer

    to limit the user's privileges.

  12. Adds the values:

    "DisableCMD" = "1"
    "DisableTaskMgr" = "1"
    "DiableRegistryTools" = "1"
    "DisableTaskMgr" = "1"


    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System

    to limit the user's privileges.

  13. Adds the values:

    "DisableConfig" = "1"
    "DisableSR" = "1"


    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\SystemRestore

    to limit the user's privileges.

  14. Adds the values:

    "DisableConfig" = "1"
    "DisableSR" = "1"


    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\SystemRestore

    to limit the user's privileges.

  15. Adds the values:

    "LimitSystemRestoreCHeckpointing" = "1"
    "DisableMSI" = "1"


    to the registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer

    to limit the user's privileges.

  16. Adds the value:

    "FullPathAddress" = "1"

    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CabinetState

    to limit the user's privileges.

  17. Adds the values:

    "HideFileExt" = "1"
    "Hidden" = "0"
    "ShowSuperHidden" = "0"


    to the registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced

    to limit the user's privileges.

  18. Disables and/or stops the following system and security-related programs:

    • AVG
    • SYMANTEC
    • PANDA
    • MCAFEE
    • PC-CILLIN
    • F-PROT
    • KASPERSKY
    • VAKSIN
    • regedit.exe
    • AVP.exe
    • rtvscan.exe
    • NAV.exe
    • VSHWIN32.exe
    • ProcessManager.exe
    • RegistryEditor.exe
    • Msiexec.exe
    • avgemc.exe
    • nvcoas.exe
    • mcvsescn.exe
    • firefox.exe
    • TASKMGR.EXE
    • setup.exe
    • Opera.exe
    • avguad.exe
    • avgnt.exe
    • killvb.exe
    • Msi.exe

  19. May use the names of files with the following extensions:

    • MDB
    • ASX
    • WMA
    • JPEG
    • PNG
    • GIF
    • C
    • WMV
    • JPG
    • MP3
    • MP4
    • MPG
    • MPEG
    • AVI
    • DAT
    • HTML
    • DOC
    • XML
    • ZIP
    • RM
    • 3GP
    • RAR
    • WSF
    • TXT
    • VBS
    • RTF
    • REG
    • PPT
    • ACF
    • JS
    • ULS
    • ASPINI
    • KEY
    • PDF
    • ASA
    • INF
    • CPP
    • DLL
    • MSI
    • bat
    • PPL

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.

Writeup By: Jeong Mun
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