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  3. W32.Mibling

W32.Mibling

Risk Level 2: Low

Discovered:
June 4, 2009
Updated:
June 4, 2009 11:49:43 PM
Type:
Worm
Systems Affected:
Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows Server 2008, Windows Vista, Windows XP
The worm may arrive on the computer as the following file with the standard Microsoft Word document icon:
%CurrentFolder%\[ORIGINAL FILE NAME].exe



Once executed, the worm copies itself as the following files:
  • C:\Documents and Settings\Administrator\Start Menu\Programs\Startup\Adobe Gamma Loader.com
  • C:\Program Files\Microsoft Office\OFFICE11\ WINWORD.EXE
  • C:\Program Files\Microsoft Office\OFFICE11\services.exe


The worm then starts Microsoft Word and opens a blank document. It then executes C:\Program Files\Microsoft Office\OFFICE11\ WINWORD.EXE to ensure infection of the compromised computer.

It then drops the following files:
  • C:\Program Files\Microsoft Office\OFFICE11\control.ini
  • C:\Program Files\Microsoft Office\OFFICE11\Drvics32.dll
  • C:\Program Files\Microsoft Office\OFFICE11\hjwgsd.dll
  • C:\Program Files\Microsoft Office\OFFICE11\jwiegh.dll
  • C:\Program Files\Microsoft Office\OFFICE11\PUB60SP.mrc
  • C:\Program Files\Microsoft Office\OFFICE11\remote.ini
  • C:\Program Files\Microsoft Office\OFFICE11\ruimsbbe.dll
  • C:\Program Files\Microsoft Office\OFFICE11\smss.exe
  • C:\Program Files\Microsoft Office\OFFICE11\yofc.dll
  • C:\Program Files\Microsoft Office\OFFICE11\ WINWORD.EXE


The worm modifies the following registry entry, so that it runs every time Windows starts:
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\"Shell" = "Explorer.exe, C:\Program Files\Microsoft Office\OFFICE11\services.exe"

The worm then creates the following registry subkeys:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Acha.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AmyMastura.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\BabyRina.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\cscript.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\csrsz.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\lsasc.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\registry.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\SMSSS.exe
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\wscript.exe


The worm then creates the following registry entries, so that the worm runs instead of the requested applications:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Acha.exe\"Debugger" = "cmd.exe /c del"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AmyMastura.exe\"Debugger" = "cmd.exe /c del"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\BabyRina.exe\"Debugger" = "cmd.exe /c del"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\cscript.exe\"Debugger" = "rundll32.exe"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\csrsz.exe\"Debugger" = "cmd.exe /c del"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\lsasc.exe\"Debugger" = "cmd.exe /c del"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\registry.exe\"Debugger" = "cmd.exe /c del"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\SMSSS.exe\"Debugger" = "cmd.exe /c del"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\wscript.exe\"Debugger" = "rundll32.exe"


The worm attempts to register a service by creating the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinDefend

It also attempts to register the service by creating the following registry entries:
  • HKEY_LOCAL_MACHINE\SYSTEM\ContrelSet\Services\WinDefend\"Start" = "4"
  • HKEY_LOCAL_MACHINE\SYSTEM\ContrelSet\Services\WinDefend\"Type" = "4"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinDefend\"Start" = "4"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinDefend\"Type" = "4"


It then modifies the following registry entries to lower security settings:
  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile\"NeverShowExt" = ""
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\"UacDisableNotify" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc\"AntiVirusDisableNotify" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc\"AntiVirusOverride" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc\FirewallDisableNotify" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc\"FirewallOverride" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc\"FirstRunDisabled" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc\"UpdatesDisableNotify" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc\"UacDisableNotify" = "1"
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system\"EnableLUA" = "0"
  • HKEY_ALL_USERS\Software\Microsoft\Office\Common\"QMSessionCount" = "2"
  • HKEY_ALL_USERS\Software\Microsoft\Office\Common\Assistant\"CurrAsstState" = "26"


It also deletes the following registry entries to prevent the compromised computer from restarting in
safe mode:
  • HKEY_LOCAL_MACHINE\SYSTEM\ContrelSet\Control\SafeBoot
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot


The worm opens a back door on the compromised computer that connects to a predetermined IRC channel allowing a remote attacker unauthorized access.

It then attempts to spread through instant messaging clients by sending any of the following messages containing a link to a file sharing Web site:
  • Mahu tips and trik menarik Adobe Photoshop, dapatkan segera buku elektronik geratis di [LINK TO WEB SITE]
  • Download segera berbagai buku elektronik tips & trik ilmu komputer di >>> [LINK TO WEB SITE]<<<
  • Download buku 1001 cara usaha mendapatkan keuntungan besar berlipat ganda & trik pengusaha sukses [LINK TO WEB SITE]
  • E-Book 1001 cara Merakit komputer ===> [LINK TO WEB SITE] geratis download


Note: At the time of writing, [LINK TO WEB SITE] represented the following remote location:
[http://]bukugeratis.4shared.com

The worm may also contact the following domains:
  • www.putera.com
  • www.tourism.gov.my
  • www.miti.gov.my

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: Nino Fred Gutierrez
Summary| Technical Details| Removal

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