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JS_DUNIHI.LF

November 14, 2016
 Analysis by: Janus Agcaoili
 ALIASES:

Troj/Dinihou-CJ (Sophos)

 PLATFORM:

Windows

 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:

Propagates via flashdrives, Downloaded from the Internet, Dropped by other malware

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. It connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.

It gathers information and reports it to its servers.

  TECHNICAL DETAILS

File Size:

119,982 bytes

File Type:

JS

Memory Resident:

Yes

Initial Samples Received Date:

10 Nov 2016

Payload:

Collects system information, Connects to URLs/IPs, Drops files, Executes files

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}.js

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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}.js""

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

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}.js <- copy of itself

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Propagation

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

  • {Removable Drive Letter}:\{Malware Filename}.js

Backdoor Routine

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

  • Execute Arbitrary Files
  • Update Itself
  • Uninstall Itself
  • Download Arbitrary Files

It connects to the following websites to send and receive information:

  • http://{BLOCKED}jhoul.noip.me:1199/is-ready

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

Dropping Routine

This worm drops the following files:

  • {Removable Drive Letter}:\{Malware Filename}.lnk <- points to the copy

Other Details

This worm gathers the following information and reports it to its servers:

  • Volume Serial ID
  • Computer Name
  • User Name
  • OS Version
  • Installed AV Softwares

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.890.02

FIRST VSAPI PATTERN DATE:

10 Nov 2016

VSAPI OPR PATTERN File:

12.891.00

VSAPI OPR PATTERN Date:

11 Nov 2016

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

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

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. {Removable Drive Letter}:\{Malware Filename}.lnk 

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as JS_DUNIHI.LF. 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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