BKDR_PLUGX.HEL

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 does not have any propagation routine.

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

It does not have any downloading capability.

It deletes the initially executed copy of itself.

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 a copy of itself in the following folders using different file names:

• %Application Data%\fgjsdft.exe (For Windows Vista and above only)
• %Windows%\fgjsdft.exe (For Windows Vista below only)

(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.. %Windows% is the Windows folder, which is usually C:\Windows.)

It creates the following folders:

• %All Users Profile%\DRM\xs

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• Global\{random}

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
fgjsdft = "%Windows%\fgjsdft.exe" (For Windows Vista below only)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
fgjsdft = "%Application Data%\fgjsdft.exe" (For Windows Vista and above only)

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
User Agent

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
User Agent\Post Platform

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
5.0\User Agent

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
5.0\User Agent\Post Platform

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

• Copy, move, rename, delete files
• Create directories
• Create files
• Enumerate files
• Execute files
• Get drive information
• Get file information
• Open and modify files
• Log keystrokes and active window
• Enumerate TCP and UDP connections
• Enumerate network resources
• Set TCP connection state
• Lock workstation
• Log off user
• Restart/Reboot/Shutdown system
• Display a message box
• Perfrom port mapping
• Enumerate processes
• Get process information
• Terminate processes
• Enumerate registry keys
• Create registry keys
• Delete registry keys
• Copy registry keys
• Enumerate registry entries
• Modify registry entries
• Delete registry values
• Screen capture
• Delete services
• Enumerate services
• Get service information
• Modify services
• Start services
• Perform remote shell
• Host Telnet server
• Connect to a database server and execute SQL statement

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

• http://{BLOCKED}uy.{BLOCKED}dler.com:53/{random generated value}
• http://{BLOCKED}uy.{BLOCKED}dler.com:8080/{random generated value}

Dropping Routine

This backdoor drops the following files:

• %All Users Profile%\DRM\xs\{random characters}

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

Download Routine

This backdoor does not have any downloading capability.

Other Details

This backdoor deletes the initially executed copy of itself

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.