BKDR_DASERF.BO
Backdoor.Daserf.B (Norton), a variant of Win32/Daserf.B trojan (ESET-NOD32)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
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 does not have any propagation routine.
It executes commands from a remote malicious user, effectively compromising the affected system. It does not have any backdoor routine.
It steals certain information from the system and/or the user.
It connects to certain websites to send and receive information. It deletes the initially executed copy of itself.
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):
- %Program Files%\Common Files\System\Library\msid.dat - If administrator
- %User Profile%\System\Library\msid.dat - If non-administrator
(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It drops the following copies of itself into the affected system:
- %Program Files%\Common Files\System\Library\dialpro.exe - If administrator
- %User Profile%\System\Library\dialpro.exe - If non-administrator
(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- qdfetqew
It injects itself into the following processes as part of its memory residency routine:
- explorer.exe
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\ControlSet001\
Services\qdfetqew
DisplayName = "Local Resource Storage Service"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\qdfetqew
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\qdfetqew
ImagePath = "%Program Files%\Common Files\System\Library\dialpro.exe"
It adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
qdfetqew = "%User Profile%\System\Library\dialpro.exe" - If non-administrator
Propagation
This backdoor does not have any propagation routine.
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Create or terminate processes
- Perform Remote Shell
- Install Services
- Start Services
- Delete Services
- Enumerate all drives with corresponding drive types
- Enumerate files and directories
- Open, Create, or Delete Files
It does not have any backdoor routine.
Information Theft
This backdoor steals the following information:
- Computer Name
- System Default Language ID
- OS Version
- Is administrator
- Is 64-bit
Other Details
This backdoor connects to the following website to send and receive information:
- http://start.{BLOCKED}otorisetsu.com/images/start.gif
- http://start.{BLOCKED}notorisetsu.com/asp/{Hard Coded String}
It deletes the initially executed copy of itself
NOTES:
Where the {Hard Coded String} can be any of the following:
- tsdhj.asp
- fhesd.asp
- vswys.asp
- zcnmw.asp
- wcfgz.asp
- sbzgt.asp
- aghet.asp
- qdjxb.asp
- jkdtx.asp
- xbedh.asp
- dxahr.asp
- ehheq.asp
- chjet.asp
- rjnhx.asp
It does not have rootkit capabilities.
It does not exploit any vulnerability.
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\ControlSet001\Services
- qdfetqew
- qdfetqew
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- qdfetqew = "%User Profile%\System\Library\dialpro.exe"
- qdfetqew = "%User Profile%\System\Library\dialpro.exe"
Step 6
Search and delete this file
- %User Profile%\System\Library\msid.dat - If non-administrator
- %Program Files%\Common Files\System\Library\msid.dat - If administrator
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_DASERF.BO. 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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