BKDR_FAKEDOBE.JB

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.

It executes commands from a remote malicious user, effectively compromising the affected system.

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 drops the following copies of itself into the affected system and executes them:

• %Application Data%\Win\WinUpdate.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It drops the following files:

• %Application Data%\log - log file of activities

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It drops and executes the following files:

• %User Temp%\{RANDOM}.bat

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It drops the following copies of itself into the affected system:

• %Application Data%\S6TD4WUQZL.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It creates the following folders:

• %Application Data%\Win

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Update = "%Application Data%\Win\WinUpdate.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL\DATE

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID\ID

It adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL\DATE
98UJ1H0LYI = "{date of first execution}"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID\ID
98UJ1H0LYI = "PM"

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\AuthorizedApplications\List
%Application Data%\Win\WinUpdate.exe = "%Application Data%\Win\WinUpdate.exe:*:Enabled:Windows Messanger"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\AuthorizedApplications\List
%Application Data%\S6TD4WUQZL.exe = "%Application Data%\S6TD4WUQZL.exe:*:Enabled:Windows Messanger"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

• Open/Close CD-Rom
• On/Off Monitor
• Shutdown/Restart machine
• Increase/Decrease/Mute Volume
• Set Screensaver
• Key logger
• Capture screenshot/video/sound
• Disable clipboard
• Set Cursor
• Swap Mouse Button
• Start/Terminate Browser
• Download File
• Get Logical Drives information
• Perform Remote Shell

It connects to the following URL(s) to send and receive commands from a remote malicious user:

• {BLOCKED}.{BLOCKED}.212.110
• {BLOCKED}.{BLOCKED}.77.13