Backdoor.Win32.TOFSEE.CBT

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.

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 adds the following processes:

• "%System%\cmd.exe" /C mkdir %Windows%\SysWOW64\dzyymwua\
• "%System%\cmd.exe" /C move /Y "%User Temp%\frqepzhb.exe" %Windows%\SysWOW64\dzyymwua\
• "%System%\sc.exe" create dzyymwua binPath= "%Windows%\SysWOW64\dzyymwua\frqepzhb.exe /d\"{malware file path and name}\"" type= own start= auto DisplayName= "wifi support"
• sc create dzyymwua binPath= "%Windows%\SysWOW64\dzyymwua\frqepzhb.exe /d\"{malware file path and name}\"" type= own start= auto DisplayName= "wifi support"
• "%System%\sc.exe" description dzyymwua "wifi internet conection"
• sc description dzyymwua "wifi internet conection"
• "%System%\sc.exe" start dzyymwua
• sc start dzyymwua
• "%System%\netsh.exe" advfirewall firewall add rule name="Host-process for services of Windows" dir=in action=allow program="%Windows%\SysWOW64\svchost.exe" enable=yes>nul
• netsh advfirewall firewall add rule name="Host-process for services of Windows" dir=in action=allow program="%Windows%\SysWOW64\svchost.exe" enable=yes>nul
• %Windows%\SysWOW64\dzyymwua\frqepzhb.exe /d"{malware file path and name}"

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It creates the following folders:

• %Windows%\SysWOW64\dzyymwua

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\dzyymwua
ImagePath = "%Windows%\SysWOW64\dzyymwua\frqepzhb.exe /d{malware file path and name}"

Other System Modifications

This Backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\dzyymwua
DisplayName = "wifi support"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\dzyymwua
Start = "SERVICE_AUTO_START"

Dropping Routine

This Backdoor drops the following files:

• %User Temp%\frqepzhb.exe
• %Windows%\SysWOW64\dzyymwua\frqepzhb.exe

(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

This report is generated via an automated analysis system.