TROJ_DLOADER.XII
TrojanDownloader:Win32/Delf.ZXG (Microsoft); Generic Downloader.x!g2s (McAfee); Trojan.Malcol (Symantec); PAK:UPX, Trojan-Downloader.Win32.Genome.cvdd (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.KD.388388 (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.
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
windows manager = "%System%\plugin.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\LSA Shell
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\advapi32.dll[MofResourceName] = "{random characters}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\ACPI.sys[ACPIMOFResource] = "{random characters}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\mssmbios.sys[MofResource] = "{random characters}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\intelppm.sys[PROCESSORWMI] = "{random characters}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\DRIVERS\ipnat.sys[IPNATMofResource] = "{random characters}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WDM
%System%\Drivers\HTTP.sys[UlMofResource] = "{random characters}"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
Name = "iexplore.exe"
(Note: The default value data of the said registry entry is iexplore.exe.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DirectDraw\MostRecentApplication
ID = "4117b81"
(Note: The default value data of the said registry entry is 41107b81.)
Dropping Routine
This Trojan drops the following files:
- %System%\config\recurso.exe
- %System%\config\csrsss.exe
- %System%\plugin.exe
(Note: %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.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://demalasprontas2014.{BLOCKED}b.com/csrsss.jpg
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_CURRENT_USER
- LSA Shell
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\Windows\CurrentVersion\Run
- windows manager = "%System%\plugin.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
- %System%\advapi32.dll[MofResourceName] = "{random characters}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
- %System%\DRIVERS\ACPI.sys[ACPIMOFResource] = "{random characters}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
- %System%\DRIVERS\mssmbios.sys[MofResource] = "{random characters}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
- %System%\DRIVERS\intelppm.sys[PROCESSORWMI] = "{random characters}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
- %System%\DRIVERS\ipnat.sys[IPNATMofResource] = "{random characters}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM
- %System%\Drivers\HTTP.sys[UlMofResource] = "{random characters}"
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\DirectDraw\MostRecentApplication
- From: Name = "iexplore.exe"
To: Name = ""iexplore.exe""
- From: Name = "iexplore.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw\MostRecentApplication
- From: ID = "4117b81"
To: ID = ""41107b81""
- From: ID = "4117b81"
Step 6
Search and delete these files
- %System%\config\recurso.exe
- %System%\config\csrsss.exe
- %System%\plugin.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLOADER.XII. 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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