TROJ_DELF.SMV
Backdoor:Win32/Zegost.B (Microsoft); Generic Dropper.kr (McAfee); Suspicious.Graybird.1 (Symantec); Trojan-Dropper.Win32.Binder.rz (Kaspersky); Trojan-Dropper.Win32.Binder.rz (v) (Sunbelt); Trojan.Generic.2099004 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan 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
211,968 bytes
EXE
Yes
25 Apr 2012
Arrival Details
This Trojan 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 Trojan creates the following folders:
- %System Root%\Documents and Settings\Local User
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{21E9C5D3-EBFF-11CD-B6FD-00AA00B4E22A}
StubPath = "%Program Files%\DBS.EXE"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{21E9C5D3-EBFF-11CD-B6FD-00AA00B4E22A}
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4
InstallModule = "%Program Files%\common files\microsoft shared\msinfo\server.exe"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4
Type = "4"
(Note: The default value data of the said registry entry is 20.)
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4
Description = "{random characters}"
(Note: The default value data of the said registry entry is Provides DDNS name registration and automatic IPv6 connectivity over an IPv4 network. If this service is stopped, other computers may not be able to reach it by name and the machine will only have IPv6 connectivity if it is connected to a native IPv6 network. If this service is disabled, any other services that explicitly depend on this service will fail to start..)
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
ServiceDll = "%User Profile%\userdata.dll"
(Note: The default value data of the said registry entry is {random values}.)
It deletes the following registry keys:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Active Setup\Installed Components\{21E9C5D3-EBFF-11CD-B6FD-00AA00B4E22A}
Dropping Routine
This Trojan drops the following files:
- %Program Files%\common files\microsoft shared\msinfo\MyServer.jpg
- %Program Files%\common files\microsoft shared\msinfo\server.jpg
- %Program Files%\common files\microsoft shared\msinfo\δÃüÃû.jpg
- %User Profile%\userdata.dll
- %Program Files%\DBS.EXE
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).. %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.)
This report is generated via an automated analysis system.
SOLUTION
9.200
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
- {21E9C5D3-EBFF-11CD-B6FD-00AA00B4E22A}
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{21E9C5D3-EBFF-11CD-B6FD-00AA00B4E22A}
- StubPath = "%Program Files%\DBS.EXE"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\6to4
- InstallModule = "%Program Files%\common files\microsoft shared\msinfo\server.exe"
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\6to4
- From: Type = "4"
To: Type = ""20""
- From: Type = "4"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\6to4
- From: Description = "{random characters}"
To: Description = ""Provides DDNS name registration and automatic IPv6 connectivity over an IPv4 network. If this service is stopped, other computers may not be able to reach it by name and the machine will only have IPv6 connectivity if it is connected to a native IPv6 network. If this service is disabled, any other services that explicitly depend on this service will fail to start.""
- From: Description = "{random characters}"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\6to4\Parameters
- From: ServiceDll = "%User Profile%\userdata.dll"
To: ServiceDll = ""{random values}""
- From: ServiceDll = "%User Profile%\userdata.dll"
Step 6
Search and delete these components
- %Program Files%\common files\microsoft shared\msinfo\MyServer.jpg
- %Program Files%\common files\microsoft shared\msinfo\server.jpg
- %Program Files%\common files\microsoft shared\msinfo\δÃüÃû.jpg
- %User Profile%\userdata.dll
- %Program Files%\DBS.EXE
Step 7
Search and delete this folder
- %System Root%\Documents and Settings\Local User
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DELF.SMV. 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 9
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Active Setup\Installed Components
- {21E9C5D3-EBFF-11CD-B6FD-00AA00B4E22A}
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