BKDR_SERKDES.B
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
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 gathers information and reports it to its servers.
TECHNICAL DETAILS
163,328 bytes
DLL
Yes
30 Nov 2017
Connects to URLs/IPs, Steals information, Executes files, Compromises system security
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:
- V1.0
Autostart Technique
This Backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Classes\
CLSID\{ECD4FC4D-521C-11D0-B792-00A0C90312E1}\InProcServer32
(Default) = {Malware Path and Filename}
Other System Modifications
This Backdoor adds the following registry entries:
HKEY_CURRENT_USER\Software\Classes\
CLSID\{ECD4FC4D-521C-11D0-B792-00A0C90312E1}\InProcServer32
ThreadingModel = Apartment
HKEY_CURRENT_USER\Software\Classes\
Folder\shellex\ContextMenuHandlers\
Microsoft
(Default) = {GUID}
HKEY_CURRENT_USER\Software\Classes\
Folder\shellex\DragDropHandlers\
Microsoft
(Default) = {GUID}
HKEY_CURRENT_USER\Software\Classes\
Folder\shellex\PropertySheetHandlers\
Microsoft
(Default) = {GUID}
HKEY_CURRENT_USER\Software\Classes\
*\shellex\PropertySheetHandlers\
Microsoft
(Default) = {GUID}
HKEY_CURRENT_USER\Software\Classes\
*\shellex\DragDropHandlers\
Microsoft
(Default) = {GUID}
Propagation
This Backdoor does not have any propagation routine.
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Update server config file (%Temp%\sysconf)
- Download/Upload arbitrary files from/to the C&C
- Create/Delete Arbitrary Files
- Take a screenshot
- List Drives, Files and Folders
- Execute arbitrary files/codes
- Terminate Processes
- Move mouse Cursor
- Simulate key presses
(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- public.{BLOCKED}p.net:443
Other Details
This Backdoor does the following:
- The C&C, proxy server, their port numbers, and the credentials for the proxy depend on the config file %Temp%\sysconf. If the said file is not present, it uses the default settings.
- By default, this backdoor may use proxy connections.
(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)
It gathers the following information and reports it to its servers:
- Host name
- User name
- MAC address
- System Default Language
- System Type (32-bit or 64-bit)
SOLUTION
9.850
13.814.04
30 Nov 2017
13.815.00
01 Dec 2017
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 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\Classes\CLSID\{ECD4FC4D-521C-11D0-B792-00A0C90312E1}\InProcServer32
- (Default) = {Malware Path and Filename}
- (Default) = {Malware Path and Filename}
- In HKEY_CURRENT_USER\Software\Classes\CLSID\{ECD4FC4D-521C-11D0-B792-00A0C90312E1}\InProcServer32
- ThreadingModel = Apartment
- ThreadingModel = Apartment
- In HKEY_CURRENT_USER\Software\Classes\Folder\shellex\ContextMenuHandlers\Microsoft
- (Default) = {GUID}
- (Default) = {GUID}
- In HKEY_CURRENT_USER\Software\Classes\Folder\shellex\DragDropHandlers\Microsoft
- (Default) = {GUID}
- (Default) = {GUID}
- In HKEY_CURRENT_USER\Software\Classes\Folder\shellex\PropertySheetHandlers\Microsoft
- (Default) = {GUID}
- (Default) = {GUID}
- In HKEY_CURRENT_USER\Software\Classes\*\shellex\PropertySheetHandlers\Microsoft
- (Default) = {GUID}
- (Default) = {GUID}
- In HKEY_CURRENT_USER\Software\Classes\*\shellex\DragDropHandlers\Microsoft
- (Default) = {GUID}
- (Default) = {GUID}
Step 5
Search and delete these files
- %Temp%\sysconf
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_SERKDES.B. 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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