BKDR_POISON.BSH
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
56,320 bytes
EXE, DLL
Yes
29 May 2013
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):
- %User Temp%\~DF82{random numbers 1}.tmp
- %User Temp%\~DF82{random numbers 2}.tmp
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
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\{GUID}
StubPath = "%Windows%:msvbkernel.exe"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{GUID}
HKEY_CLASSES_ROOT\My20130401.Document
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document
Other Details
This backdoor connects to the following possibly malicious URL:
- https://premium.{BLOCKED}linux.com
SOLUTION
9.300
9.948.02
29 May 2013
9.949.00
30 May 2013
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
- My20130401.Document
- My20130401.Document
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
- My20130401.Document
- My20130401.Document
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
- {GUID}
- {GUID}
Step 4
Search and delete these files
- %User Temp%\~DF82{random numbers 1}.tmp
- %User Temp%\~DF82{random numbers 2}.tmp
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_POISON.BSH. 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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