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Worm.Win32.DUNGCOI.A

December 16, 2024
 Analysis by: Thea Patrice Tajonera
 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via removable drives, Propagates via instant messaging applications


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 drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

57,344 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Jan 2021

Payload:

Connects to URLs/IPs, Downloads files

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:

  • %Windows%\system\Fun.exe
  • %Windows%\system\dc.exe
  • %Windows%\SVIQ.EXE
  • %Windows%\inf\Other.exe
  • %System%2\WinSit.exe
  • %System%\config\Win.exe
  • %Windows%\Help\Other.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following files:

  • %Windows%\wininit.ini
  • %System%\Xpen.dat
  • %System%\Penx.dat

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It adds the following processes:

  • %Windows%\system\Fun.exe
  • %Windows%\dc.exe
  • %Windows%\SVIQ.EXE

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Autostart Technique

This Worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
run = %System%\config\Win.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = %Windows%\inf\Other.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
dc2k5 = %Windows%\SVIQ.EXE

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Fun = %Windows%\system\Fun.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
dc = %Windows%\dc.exe

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = %Windows%\inf\Other.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = Explorer.exe %System%\WinSit.exe

(Note: The default value data of the said registry entry is explorer.exe.)

Propagation

This Worm drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

Download Routine

This Worm accesses the following websites to download files:

  • http://{BLOCKED}vb.googlepages.com/ND.txt
  • http://{BLOCKED}ivb.googlepages.com/NWB.txt

As of this writing, the said sites are inaccessible.

Other Details

This Worm does the following:

  • It also has the capability to propagate using the Instant Messaging application Yahoo! Messenger. Where it may use any of the following text in the instant message along with the aforementioned links where a copy of itself can be downloaded:
    • Chuc mung, ban da tam thoi thoat khoi Worm DungCoi {LINK}
    • Olalala, may tinh cua ban da dinh Worm DungCoi........... {LINK}

    However since the Yahoo Messenger application is no longer active, it will not be able to perform this routine.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

16.476.06

FIRST VSAPI PATTERN DATE:

14 Jan 2021

VSAPI OPR PATTERN File:

16.477.00

VSAPI OPR PATTERN Date:

15 Jan 2021

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     
    • Troj.Win32.TRX.XXPE50FFF039

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

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 NT\CurrentVersion\Windows
    • run = %System%\config\Win.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • load = %Windows%\inf\Other.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • dc2k5 = %Windows%\SVIQ.EXE
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Fun= %Windows%\system\Fun.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • dc = %Windows%\dc.exe

Step 6

Restore this modified 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "Explorer.exe %System%\WinSit.exe"
      To: Shell = "Explorer.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • From: load = "%Windows%\inf\Other.exe"
      To: load = ""

Step 7

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.
  • %Windows%\system\Fun.exe
  • %Windows%\system\dc.exe
  • %Windows%\SVIQ.EXE
  • %Windows%\inf\Other.exe
  • %System%2\WinSit.exe
  • %System%\config\Win.exe
  • %Windows%\Help\Other.exe
  • {Removable Drive}\{Pre-existing Folder}\{Pre-existing Folder Number}.exe
  • %Windows%\wininit.ini
  • %System%\Xpen.dat
  • %System%\Penx.dat

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.DUNGCOI.A. 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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