TROJ_INJECT.BHU
Trojan:Win32/Inject.AL (Microsoft); Generic.dx!bbr4 (McAfee); Trojan.Gen (Symantec); Trojan-Dropper.Win32.Agent.gcsg (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.6723427 (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
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:
- %User Profile%\Application Data\VMware
- %User Profile%\Microsoft\Dr Watson
- %Windows%\SoftwareDistribution\DataStore\Logs\
- %Windows%\SoftwareDistribution\DataStore
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
System Canvas = "RunDll32 "%System%\CatRoot2\hostsrv.dll",Init"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
System Canvas = "RunDll32 "%Windows%\loghost.dll",Init"
Other System Modifications
This Trojan deletes the following files:
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Active Setup External
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Active Setup External
IdIdIdPermissionIdSec = {random values}
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
Shell = "explorer.exe,RunDll32 "%Program Files%\Common Files\Services\lsaetet.dll",Init"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
Shell = "explorer.exe,RunDll32 "%System%\mui\0408\mssvcup.dll",Init"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
AppInit_Dlls = "%Windows%\lsaperf.dll"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DrWatson
NumberOfCrashes = 1
(Note: The default value data of the said registry entry is 0.)
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting\DW
Dropping Routine
This Trojan drops the following files:
- %User Temp%\1.tmp
- %User Profile%\Application Data\Microsoft
- %User Profile%\Microsoft\Crypto
- %User Profile%\Crypto\RSA
- %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
- %User Profile%\RSA\S-1-5-18
- %User Profile%\Dr Watson\drwtsn32.log
- %User Profile%\Dr Watson\user.dmp
- %System%\CatRoot2\hostsrv.dll
- %Program Files%\Common Files\Services\lsaetet.dll
- %Windows%\lsaperf.dll
- %Windows%\loghost.dll
- %System%\mui\0408\mssvcup.dll
(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.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Program Files% is the default Program Files folder, usually C:\Program Files.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
This report is generated via an automated analysis system.
SOLUTION
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
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
- Active Setup External
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
- System
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\Microsoft\Windows\CurrentVersion\Run
- System Canvas="RunDll32 "%System%\CatRoot2\hostsrv.dll",Init"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- System Canvas="RunDll32 "%Windows%\loghost.dll",Init"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Active Setup External
- IdIdIdPermissionIdSec={random values}
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
- Shell="explorer.exe,RunDll32 "%Program Files%\Common Files\Services\lsaetet.dll",Init"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
- Shell="explorer.exe,RunDll32 "%System%\mui\0408\mssvcup.dll",Init"
Step 5
Restore this modified 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\Windows NT\CurrentVersion\Windows
- AppInit_Dlls="%Windows%\lsaperf.dll"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DrWatson
- From: NumberOfCrashes=1
To: NumberOfCrashes=0
- From: NumberOfCrashes=1
Step 6
Search and delete these folders
- %User Profile%\Application Data\VMware
- %User Profile%\Microsoft\Dr Watson
- %Windows%\SoftwareDistribution\DataStore\Logs\
- %Windows%\SoftwareDistribution\DataStore
Step 7
Search and delete these files
- %User Temp%\1.tmp
- %User Profile%\Application Data\Microsoft
- %User Profile%\Microsoft\Crypto
- %User Profile%\Crypto\RSA
- %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
- %User Profile%\RSA\S-1-5-18
- %User Profile%\Dr Watson\drwtsn32.log
- %User Profile%\Dr Watson\user.dmp
- %System%\CatRoot2\hostsrv.dll
- %Program Files%\Common Files\Services\lsaetet.dll
- %Windows%\lsaperf.dll
- %Windows%\loghost.dll
- %System%\mui\0408\mssvcup.dll
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_INJECT.BHU. 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 this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again. %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
Step 10
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_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
- DW
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