BKDR_POISON.TUHC
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
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.
It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.
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 adds the following mutexes to ensure that only one of its copies runs at any one time:
- hfdkoream
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{random GUID}
StubPath = "{malware path and file name}"
It is a .DLL file that adds the following services:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SymantecAuthdService
ImagePath = "{Malware Path}\mcods.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SymantecAuthdService
Display Name = Symantec Authorization Service
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SymantecAuthdService
Description = Symantec Authorization and authentication service for starting and accessing secure machines
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Capture screen shots, webcam, audio
- Delete, search, and upload files
- Download and inject remote codes to legitimate processes
- Log keystrokes and active window
- Manage processes and services
- Modify and search the registry entries
- Perform a shell command
- Send system information (IP address, computer name, user name, operating system)
- Update/Uninstall the malware
- View and terminate active windows and ports
It connects to the following websites to send and receive information:
- musiconline.{BLOCKED}e.com:443
- {BLOCKED}.{BLOCKED}.160.216:443
However, as of this writing, the said sites are inaccessible.
Other Details
This backdoor requires the existence of the following files to properly run:
- {Malware Path}\mcods.exe <- non-malicious, used by the malware to load the malicious dll
It does the following:
- It queries the default web browser by accessing the following registry entry:
- HKEY_CLASSES_ROOT\http\shell\open\command
- It then launches a hidden Web browser process (e.g. iexplore.exe) and then injects its code to the said process.
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
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.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- SymantecAuthdService
- SymantecAuthdService
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\SOFTWARE\Microsoft\Active Setup\Installed Components\{random GUID}
- StubPath = {malware path and file name}
- StubPath = {malware path and file name}
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_POISON.TUHC. 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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