BKDR_PLUGX.BIN
W32/Plugx.AP!tr (Fortinet); Troj/Plugx-AP (Sophos); Win32.Trojan.Korplug.Pikp (Tencent); TR/Korplug.8704.5 (Avira); Trojan.Win32.Korplug.ET (Baidu-International)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
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.
It does not have any propagation routine.
It executes commands from a remote malicious user, effectively compromising the affected system.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
8,704 bytes
DLL
Yes
21 Jul 2015
Connects to URLs/IPs, Compromises system security, Drops files
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 files:
- %All Users Profile%\DRM\vncutil\vncutil.exe - normal file used to load vncutilLOC.dll
- %All Users Profile%\DRM\vncutil\vncutilLOC.dll - copy of itself, detected as BKDR_PLUGX.BIN
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 adds the following processes:
- svchost.exe
It creates the following folders:
- %All Users Profile%\DRM\vncutil
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 adds the following mutexes to ensure that only one of its copies runs at any one time:
- My_Name1
It injects codes into the following process(es):
- created svchost.exe
Autostart Technique
This backdoor 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\vncutil
It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\vncutil
ImagePath = "%All Users Profile%\DRM\vncutil\vncutil.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\vncutil
DisplayName = "vncutil"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\vncutil
Description = "Noise Canceling Program"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\vncutil
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\vncutil
Type = "272"
Other System Modifications
This backdoor adds the following registry entries:
HKEY_CURRENT_USER\Software\BINARY
vncutil = "{hex values}" - config data
HKEY_LOCAL_MACHINE\SOFTWARE\BINARY
vncutil = "{hex values}" - config data
Propagation
This backdoor does not have any propagation routine.
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Copy, move, rename, delete files
- Create directories
- Create files
- Enumerate files
- Execute files
- Get drive information
- Get file information
- Open and modify files
- Log keystrokes and active window
- Enumerate TCP and UDP connections
- Enumerate network resources
- Set TCP connection state
- Lock workstation
- Log off user
- Restart/Reboot/Shutdown system
- Display a message box
- Perfrom port mapping
- Enumerate processes
- Get process information
- Terminate processes
- Enumerate registry keys
- Create registry keys
- Delete registry keys
- Copy registry keys
- Enumerate registry entries
- Modify registry entries
- Delete registry values
- Screen capture
- Delete services
- Enumerate services
- Get service information
- Modify services
- Start services
- Perform remote shell
- Host Telnet server
- Connect to a database server and execute SQL statement
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- http://{BLOCKED}l.naengmyeon.net:443/{random values}
As of this writing, the said sites are inaccessible.
Dropping Routine
This backdoor drops the following files:
- %All Users Profile%\DRM\vncutil\{random file name 1} - encrypted data
- %All Users Profile%\DRM\vncutil\{random file name 2} - encrypted data
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)
Other Details
This backdoor deletes the initially executed copy of itself
NOTES:
If the “%All Users Profile%\DRM” folder is not present in the affected machine, it will drop its files in:
- “%All Users Profile%\vncutil\” (for Windows XP and below)
- “%Program Data%\vncutil” (for Windows Vista and above)
SOLUTION
9.750
11.822.05
30 Jul 2015
11.823.00
31 Jul 2015
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
Restart in Safe Mode
Step 4
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_CURRENT_USER\Software
- BINARY
- BINARY
- In HKEY_LOCAL_MACHINE\Software
- BINARY
- BINARY
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- vncutil
- vncutil
Step 5
Search and delete these folders
- %All Users Profile%\DRM\vncutil
Step 6
Scan your computer with your Trend Micro product to delete files detected as BKDR_PLUGX.BIN. 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.
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_PLUGX.BIN. 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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