Worm.VBS.DUNIHI.AAYSYT

This Worm 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. However, as of this writing, the said sites are inaccessible.

It gathers certain information on the affected computer.

Arrival Details

This Worm 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 Temp%\{Malware Name}.vbs
• %User Startup%\{Malware Name}.vbs
• {Infected Removable Drive}:\{Malware Name}.vbs → attributes set to System & Hidden

(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).. %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, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

It adds the following processes:

• "%System%\wscript.exe" //B "%User Temp%\{Malware Name}.vbs"

(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).)

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 Name} = wscript.exe //B "%User Temp%\{Malware Name}.vbs"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware Name} = wscript.exe //B "%User Temp%\{Malware Name}.vbs"

Other System Modifications

This Worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware Name}.vbs
(Default) = {true/false} - {Date that the malware run}

Propagation

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

• {Infected Drive}:\{Malware Name}.vbs → attributes set to System & Hidden

It creates shortcut files (.LNK) disguised as folders or files located on the affected drives pointing to the malware copy.

Backdoor Routine

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

• "execute" - Executes arbitrary command from the C&C server
• "update" - Updates malware code and restart the malware
• "uninstall" - Uninstalls the malware
• "send" - Downloads a file from the C&C server, saves it in a specified directory and run it
• "site-send" - Downloads a file from the C&C server and run it
• "recv" - Sends a file from a specified URL to the C&C server
• "enum-driver " - Retrieves list of drives
• "enum-faf" - Retrieves information about files and folders in a specified directory
• "enum-process" - Retrieves information about running processes
• "cmd-shell" - Executes a command using Command Prompt and retrieves its output
• "delete" - Deletes a file or folder
• "exit-process" - Forcefully terminates a process and all its children
• "sleep" - Running script sleeps for a specified amount of time

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

• http://{BLOCKED}ny0501.no-ip.biz:50007/

However, as of this writing, the said sites are inaccessible.

Information Theft

This Worm gathers the following information on the affected computer:

• Computer Name
• Username
• OS Name
• Volume Serial Number
• Every Antivirus Installed in System

Other Details

This Worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware Name}

It does the following:

• It sets the attributes of non-LNK files and folders in the infected drive to System & Hidden