VBS_DUNIHI.SM2

 Analysis by: Rika Joi Gregorio

 ALIASES:

Worm:VBS/Jenxcus.K(Microsoft), VBS.Dunihi(Symantec), VBS/Autorun.worm.aapj(McAfee), VBS/Agent.NDH worm(Eset)

 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: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Via email, Downloaded from the Internet


This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users. 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.

  TECHNICAL DETAILS

File Size:

14,029 bytes

File Type:

VBS

Memory Resident:

Yes

Initial Samples Received Date:

25 Mar 2014

Payload:

Compromises system security, Connects to URLs/IPs, Steals information

Arrival Details

This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

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 and executes them:

  • %User Temp%\{malware file 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, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It drops the following files:

  • {drive letter}:\{folder / file name}.lnk

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 file name} = "wscript.exe //B "%User Temp%\{malware file name}.vbs""

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

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

  • %User Startup%\{malware file name}.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 file name}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{malware file name}
(Default) = "{true or false (if executed from removable drive)} - {date of first execution}"

Propagation

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

  • {drive letter}:\{malware file name}.vbs

Backdoor Routine

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

  • Execute files
  • Update itself
  • Uninstall itself
  • Donwnload files
  • Upload files
  • Enumerate drivers
  • Enumerate files and folders
  • Enumerate processes
  • Perform remote shell
  • Delete files and folders
  • Terminate process
  • Sleep

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

  • http://{BLOCKED}.{BLOCKED}.186.27:288/is-ready
  • http://{BLOCKED}no.no-ip.org:1806/is-ready
  • http://{BLOCKED}ajjar.no-ip.biz:12345/is-ready
  • http://herohero.{BLOCKED}p.org:96/is-ready
  • http://s-mz.{BLOCKED}s.net:30516/is-ready

Information Theft

This worm gathers the following data:

  • Computer name
  • Host name
  • OS Version
  • Installed AV products
  • Volume serial number

NOTES:

This worm creates .LNK (shortcut) files using folder or file names found in removable drives. It then hides the original folder/file tricking users to click .LNK files. This .LNK files point out to a dropped copy of itself in the removable drive.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.300.04

FIRST VSAPI PATTERN DATE:

26 Sep 2013

VSAPI OPR PATTERN File:

10.301.00

VSAPI OPR PATTERN Date:

26 Sep 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • {malware file name}

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {malware file name} = "wscript.exe //B "%User Temp%\{malware file name}.vbs""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {malware file name} = "wscript.exe //B "%User Temp%\{malware file name}.vbs""

Step 5

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • {drive letter}:\{folder / file name}.lnk

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as VBS_DUNIHI.SM2. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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