Arrival Details
This malware may be dropped by the following malware:
Installation
This malware adds the following mutexes to ensure that only one of its copies runs at any one time:
Autostart Technique
This malware registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MSNDSRV
Options = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MSNDSRV
Config = "MSCFG32.EXE"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\MSNDSRV
Type = "1" --> this entry classifies the file as a kernel device driver
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\MSNDSRV
Start = "2" --> this entry allows the driver to be loaded or started automatically for all startups regardless of of type
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\MSNDSRV
2 = "F|\??\C:\Windows\system32\mscfg32.dll|F|\SystemRoot\system32\SPOOL2|F|\SystemRoot\system32\mslog32.dat|F|\??\C:\Windows\system32\mscfg32.dll"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MSNDSRV
ErrorControl = "0" --> no error is displayed if the driver can't be loaded or started
It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MSNDSRV
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\MSNDSRV
Other System Modifications
This malware adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
{42E14DD3-F07A-78F1-7659-26AE141569AC-E0B3EE89} = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
{A0CCDC61-7623-A425-7002-DB81F353945F-5A8ECFAD} = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
1 = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
I4 = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
I1 = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
I2 = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
I3 = "{hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager\MemSubSys
I5 = "{hex values}"
Rootkit Capabilities
This malware also has rootkit capabilities, which enables it to hide its processes and files from the user.
Other Details
This malware drops the following file(s)/component(s):
- %System%\MSDIRECTX.exe
- %System%\MSCFG32.DLL
- %System%\MSCFG32.EXE
- %System%\drivers\MSNDSRV.SYS
- %User Temp%\INSTV4.BAT
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It creates the following event(s):
- EE334FEA
- BCAf8489
- 95238543
- D0385CB7-B834-45D1-1A1700E6C34E
NOTES:
The file %System%\MSDIRECTX.EXE opens the following events created by the main file:
- EE334FEA
- BCAf8489
- 95238543
It also downloads a Certificate Revocation List (CRL) file from the following:
- http://crl.microsoft.com/pki/crl/products/WinIntPCA.crl
This file is deleted by a batch file it creates. It also deletes itself.
The malware loads the driver (%System%\drivers\MSNDSRV.SYS) it created.This file is the one responsible for hooking System Service Dispatch Table (SSDT).
The file %User Temp%\INSTV4.BAT deletes the main file, and deletes itself afterwards.
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Identify and delete files detected as RTKT_DOTTUN.VTH using either the Startup Disk or Recovery Console
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To identify and delete the malware/grayware file:
• On Windows XP and Server 2003 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Click Start>Run. In the Open input box, type secpol.msc and press Enter.
- In the left panel, double-click Local Policies>Security Options.
- In the right panel, double-click Recovery Console: Allow floppy copy and access to all drives and folders.
- Select Enabled and click OK.
- Insert the Windows Installation CD into the CD drive, then restart your computer.
- When prompted, press any key to boot from the CD.
- On the main menu, type r to go to the Recovery Console.
- Type the number that corresponds to the drive and directory that contains Windows (usually C:\WINDOWS) and press Enter.
- Type the Administrator password and press Enter.
- In the input box, type the following then press Enter:
SET AllowAllPaths = TRUE
del "{malware/grayware path and file name}" - Type exit and press Enter to restart the system normally.
• On Windows Vista, 7, and Server 2008 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Insert your Windows Installation DVD in the DVD drive, then Press the restart button.
- When prompted, press any key to boot from the CD.
- Depending on your Windows Installation DVD, you might be required to select the installation language. Then on the Install Windows window, choose your language, locale, and keyboard layout or input method. Click Next, then click Repair your computer.
- Select Use recovery tools that can help fix problems starting Windows. Select your installation of Windows. Click Next.
- If the Startup Repair window appears, click Cancel, Yes, then Finish.
- In the System Recovery Options window, click Command Prompt.
- In the Command Prompt window, type the following then press Enter:
BootRec.exe /fixmbr
del "{malware/grayware path and file name}" - Type exit and press Enter to close the Command Prompt window.
- Click Restart to restart the system normally.
• On Windows 8, 8.1, and Server 2012 systems:
- Scan your computer with your Trend Micro product and then take note of the names of the malware/grayware files detected.
- Insert your Windows Installation DVD in the DVD drive, then restart your computer.
- When prompted, press any key to boot from the DVD.
- Depending on your Windows Installation DVD, you might be required to select the keyboard layout. Then on the Windows Setup window, choose your language, locale, and input method. Click Next, then click Repair your computer.
- Click Troubleshoot>Advanced Options>Command Prompt.
- In the Command Prompt window, type the following then press Enter:
BootRec.exe /fixmbr
del "{malware/grayware path and file name}" - Type exit and press Enter to close the Command Prompt window.
- Click Continue to restart the system normally.
Step 4
Restart in Safe Mode
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista, Windows 7, and Windows Server 2008 users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
• For Windows 8, Windows 8.1, and Windows Server 2012 users
- Access the Charms bar by moving your mouse pointer to the upper right corner of the screen.
- Move your mouse pointer down and click Settings>Change your PC Settings.
- In the left panel, click General.
- In the right panel, scroll down to the bottom to find the Advanced startup section, then click the Restart now button and wait for the system to restart.
- In the Advanced Startup menu, click Troubleshoot>Advanced Options>Startup Settings>Restart and wait for the system to restart.
- In the Startup Settings menu, press 4 to enable safe mode.
Step 5
Delete this registry key
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Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSNDSRV
- HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\MSNDSRV
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\MemSubSys
To delete registry keys this malware/grayware created:
- Open Registry Editor. To do this:
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type regedit in the text box provided, and then press Enter.
» For Windows Vista, Windows 7, and Windows Server 2008 users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter. - HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\MSNDSRV
- HKEY_LOCAL_MACHINE\\SYSTEM\\ControlSet001\\Services\\MSNDSRV
- HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\Session Manager\\MemSubSys
- Close Registry Editor.
Step 6
Search and delete these files
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There may be some files that are hidden. Please make sure you check the
Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
- %System%\MSDIRECTX.exe
- %System%\MSCFG32.DLL
- %System%\MSCFG32.EXE
- %System%\drivers\MSNDSRV.SYS
- %User Temp%\INSTV4.BAT
To delete malware/grayware files:
For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the File name* input box, type
- %System%\MSDIRECTX.exe
- %System%\MSCFG32.DLL
- %System%\MSCFG32.EXE
- %System%\drivers\MSNDSRV.SYS
- %User Temp%\INSTV4.BAT
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
- Repeat the said steps for all files listed.
*Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).
For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:
- Open a Windows Explorer window.
- For Windows Vista, 7, and Server 2008 users, click Start>Computer.
- For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
- In the Search Computer/This PC input box, type:
- %System%\MSDIRECTX.exe
- %System%\MSCFG32.DLL
- %System%\MSCFG32.EXE
- %System%\drivers\MSNDSRV.SYS
- %User Temp%\INSTV4.BAT
- Once located, select the file then press SHIFT+DELETE to delete it.
- Repeat the said steps for all files listed.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RTKT_DOTTUN.VTH. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
