TROJ_DROPPER.QVA
Windows XP, 2000, 2003, Vista
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan may be dropped by other malware.
TECHNICAL DETAILS
Arrival Details
This Trojan may be dropped by the following malware:
- TROJ_TARODRP.SM
Other System Modifications
This Trojan adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager
PendingFileRenameOperations = \??\C:\WINDOWS\ntshrui.dll
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager
AllowProtectedRenames = 1
Other Details
This Trojan does the following:
- It checks if the current user has admin rights in the system. If the user of the system has no admin rights, it then checks the startup folders of the system by getting the data of the value "Startup" in the following registry entry:
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
- It then checks if the running process on the system is %User Profile%\Start Menu\Programs\Startup\Adobe_u.exe. If yes, it creates the following file:
- %User Profile%\netui0.dll - detected as BKDR_GOLPECO.A
- The dropped file is then injected to explorer.exe.
- If %User Profile%\Start Menu\Programs\Startup\Adobe_u.exe is not the running process, it copies itself in the startup folder as follows:
- %User Profile%\Start Menu\Programs\Startup\Adobe_u.exe
- It then performs the following command to delete the currently running file:
- %User Profile%\Start Menu\Programs\Startup\Adobe_u.exe –s {executed malware file}
- If the user of the system has admin rights, it checks for the existence of the following key:
- HKEY_Local_Machine\Software\Jiangmin
- It then drops the following file:
- %User Profile%\ntshrui.dll - copy of netui0.dll, detected as BKDR_GOLPECO.A
- It then sets the timestamp of the dropped file using the timestamp of the normal %System%\ntshrui.dll.
- It creates the following registry keys so to copy its component file to %Windows% and load it as normal system file once the system starts up:
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\??\C:\Documents and Settings\WinXP\ntshrui.dll
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\??\C:\Documents and Settings\WINDOWS\ntshrui.dll
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
SOLUTION
Step 1
For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 3
Scan your computer with your Trend Micro product and note files detected as TROJ_DROPPER.QVA
Step 4
Restart in Safe Mode
Step 5
Delete this registry value
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.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
- PendingFileRenameOperations = \??\C:\WINDOWS\ntshrui.dll
- PendingFileRenameOperations = \??\C:\WINDOWS\ntshrui.dll
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
- AllowProtectedRenames = 1
- AllowProtectedRenames = 1
Step 6
Delete this registry key
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.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\??\C:\Documents and Settings\WinXP
- ntshrui.dll
- ntshrui.dll
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\??\C:\Documents and Settings\WINDOWS\
- ntshrui.dll
- ntshrui.dll
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DROPPER.QVA 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.
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