VBS_AGENT.YJF

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.

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 Temp%\{Malware Filename}.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, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp 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 Temp%\{Malware Filename}.vbs""

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

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

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

(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

Other Details

This worm connects to the following possibly malicious URL:

• http://{BLOCKED}-search.{BLOCKED}ttp.com:3313/is-ready
• http://{BLOCKED}-search.{BLOCKED}ttp.com:3313/is-enum-driver
• http://{BLOCKED}-search.{BLOCKED}ttp.com:3313/is-enum-faf
• http://{BLOCKED}-search.servehttp.com:3313/is-enum-process
• http://{BLOCKED}-search.servehttp.com:3313/is-cmd-shell
• http://{BLOCKED}-search.servehttp.com:3313/is-sending
• http://{BLOCKED}-search.servehttp.com:3313/is-recving

NOTES:

This worm drops shortcut files pointing to the copy of itself in removable drives. These dropped .LNK files use the names of the folders and files located on the said drives for their file names. It then sets the attributes of the original folders to System and Hidden to trick the user into clicking the .LNK files.