TROJ_TIGGRE.H

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.

It executes then deletes itself afterward.

It modifies the Internet Explorer Zone Settings.

It gathers certain information on the affected computer.

It connects to certain websites to send and receive information.

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 drops the following files:

• %User Temp%\winhelp.dat -> (deleted afterwards)
• %User Temp%\~Update.lnk -> (deleted afterwards) target location: C:\Windows\system32\control.exe C:\PROGRA~1\COMMON~1\services\winhelp.cpl
• %User Startup%\Microsoft.lnk -> renamed "~Update.lnk"
• %ProgramData%\Microsoft\Windows\Start Menu\Programs\Startup\Microsoft.lnk -> if not admin
• %Program Files%\Common Files\Services\winhelp.dat -> (deleted afterwards) MS Cab file
• %Application Data%\microsoft\credentials\winhelp.dat -> alternative location if dropping is not successful
• %Program Files%\Common Files\Services\winhelp.cpl -> extracted from winhelp.dat
• %Application Data%\microsoft\credentials\winhelp.cpl -> alternative location if dropping is not successful

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %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.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following processes:

• control C:\PROGRA~1\COMMON~1\services\winhelp.cpl
• "C:\Windows\system32\rundll32.exe" Shell32.dll,Control_RunDLL C:\PROGRA~1\COMMON~1\services\winhelp.cpl

It executes then deletes itself afterward.

Autostart Technique

This Trojan registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\helpsvc
ImagePath = "%SystemRoot%\System32\svchost.exe -k netsvcs"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\helpsvc
DisplayName = "Windows Multimedia Service"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\helpsvc
Description = "Windows Multimedia Service for media devices"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\helpsvc\Parameters
ServiceDll = "C:\PROGRA~1\COMMON~1\services\winhelp.cpl"

Other System Modifications

This Trojan deletes the following files:

• %User Startup%\Microsoft.lnk
• %ProgramData%\Microsoft\Windows\Start Menu\Programs\Startup\Microsoft.lnk -> if not admin

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Information Theft

This Trojan gathers the following information on the affected computer:

• Computer name
• Volume serial number
• Microsoft Windows version
• CPU speed
• ANSI code page
• OEM code page identifier for the operating system
• Physical and virtual memory information

Other Details

This Trojan connects to the following website to send and receive information:

• www.{BLOCKED}dxp.com