BKDR_PLUGX.BS
Backdoor:Win32/Plugx.B (Microsoft), a variant of Win32/Korplug.AG trojan (NOD32)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
Arrival Details
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This backdoor drops the following file(s)/component(s):
- %All Users Profile%\NVIDIA MAX\Nv.exe
- %All Users Profile%\NVIDIA MAX\NvSmart.hlp
- %All Users Profile%\NVIDIA MAX\NvSmartMax.cpu
- %All Users Profile%\NVIDIA MAX\NvSmartMax.dll
(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)
It creates the following folders:
- %All Users Profile%\NVIDIA MAX
(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)
Autostart Technique
This backdoor 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\NVIDIA Smart Maximise Helper Host
Type = "110"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NVIDIA Smart Maximise Helper Host
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NVIDIA Smart Maximise Helper Host
ErrorControl = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NVIDIA Smart Maximise Helper Host
ImagePath = "%All Users Profile%%\NVIDIA MAX\Nv.exe" 200 0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NVIDIA Smart Maximise Helper Host
DisplayName = "NVIDIA Smart Maximise Helper Host"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NVIDIA Smart Maximise Helper Host
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NVIDIA Smart Maximise Helper Host
Description = "NVIDIA Smart Maximise Helper Host"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_CLASSES_ROOT\FAST
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
User Agent
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
User Agent\Post Platform
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
5.0\User Agent
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
5.0\User Agent\Post Platform
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
FAST
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NVIDIA Smart Maximise Helper Host
It adds the following registry entries as part of its installation routine:
HKEY_CLASSES_ROOT\FAST
CLSID = "{Hex Values}"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
FAST
CLSID = "{Hex Values}"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = "0"
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_CONFIG\Software\Microsoft\
windows\CurrentVersion\Internet Settings
ProxyEnable = "0"
(Note: The default value data of the said registry entry is 1.)
SOLUTION
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
Restart in Safe Mode
Step 3
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_CLASSES_ROOT
- FAST
- FAST
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- User Agent
- User Agent
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\User Agent
- Post Platform
- Post Platform
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\5.0
- User Agent
- User Agent
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\5.0\User Agent
- Post Platform
- Post Platform
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
- FAST
- FAST
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- NVIDIA Smart Maximise Helper Host
- NVIDIA Smart Maximise Helper Host
Step 4
Restore this modified 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- From: ProxyEnable = "0"
To: ProxyEnable = "1"
- From: ProxyEnable = "0"
- In HKEY_CURRENT_CONFIG\Software\Microsoft\windows\CurrentVersion\Internet Settings
- From: ProxyEnable = "0"
To: ProxyEnable = "1"
- From: ProxyEnable = "0"
Step 5
Search and delete this folder
- %All Users Profile%\NVIDIA MAX
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_PLUGX.BS. 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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