VBS_DUNIHI.E

 Analysis by: Ardin Christopher Maglalang

 ALIASES:

VBS/Agent.NDH(ESET), VBS/Agent.ooo(ANTIVIR)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

1,283,575 bytes

File Type:

VBS

Initial Samples Received Date:

16 Dec 2013

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:

  • %Application Data%\{Malware Filename}.vbe

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

HKEY_CURRENT_USER\software\microsoft\
windows\currentversion\runOnce
{Malware Filename} = "wscript.exe //B "%Application Data%\{Malware Filename}.vbe""

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}.vbe

Backdoor Routine

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

  • http://search.{BLOCKED}ttp.com:358/{Command\Status}

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.