VBS_DUNIHI.EW

This worm arrives via removable drives. It 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 worm arrives via removable drives.

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

• %User Profile%\{Malware Filename}.vbe

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware Filename} = "wscript.exe //B "%User Profile%\{Malware Filename}.vbe""

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{Malware Filename} = "wscript.exe //B "%User Profile%\{Malware Filename}.vbe""

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

• %User Startup%\{Malware Filename}.vbe

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware Filename}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware Filename}
(Default) = "{true\false} - {date executed}"

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

• {Drive Letter}:\{Malware Filename}.vbs

Backdoor Routine

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

• Execute commands
• Update and uninstall itself
• Upload and download files
• Enumerate files and folders
• Enumerate drivers
• Delete files
• Remote Command Shell
• Terminate process
• Sleep (Idle)

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

• {BLOCKED}ria.zapto.org:1644

NOTES:
It drops shortcut files pointing to the copy of itself in removable drives. These dropped .LNK files use the names of the files located on the said drives for their file names. It then sets the attributes of the original folders to Hidden to trick the user into clicking the .LNK files. When the .LNK has been executed it will trigger execution of the malware VBS_DUNIHI.EW.