Worm.WSF.DUNIHI.PAT

 Analysis by: Patrick Noel Collado

 ALIASES:

JS/TrojanDropper.Agent.NYR trojan (NOD32), JS:Trojan.Cryxos.27 (Bitdefender)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Via physical/removable drives, Downloaded from the Internet


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 drops copies of itself into all the removable drives connected to an affected system.

It executes commands from a remote malicious user, effectively compromising the affected system.

It logs a user's keystrokes to steal information.

  TECHNICAL DETAILS

File Type:

WSF

Memory Resident:

Yes

Initial Samples Received Date:

06 Feb 2020

Payload:

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

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 and executes them:

  • %Application Data%\{Malware Name}.wsf

(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It drops the following files:

  • %User Temp%\ebgeaegdbdecaedfebace.reg

(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • regedit.exe %User Temp%\ebgeaegdbdecaedfebace.reg

(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

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 Name} = wscript.exe //B "%Application Data%\{Malware Name}.wsf"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware Name} = wscript.exe //B "%Application Data%\{Malware Name}.wsf"

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

  • %User Startup%\{Malware Name}.wsf

(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, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Other System Modifications

This Worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware Name}
(Default) = {true or false} - {Date of Infection}

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\{Malware Name}

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorAdmin = 0

(Note: The default value data of the said registry entry is 3.)

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = 1

(Note: The default value data of the said registry entry is 0.)

Propagation

This Worm drops copies of itself into all the removable drives connected to an affected system.

It creates shortcut files (.LNK) disguised as folders or files located on the affected drives pointing to the malware copy.

Backdoor Routine

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

  • disconnect - Terminate malware process
  • reboot - Reboot the machine
  • shutdown - Shutdown the machine
  • execute - Execute command sent by C&C
  • install-sdk - Install tool used for stealing passwords from web browsers
  • get-pass - Steal passwords from a specific web browser
  • get-pass-offline - Steal passwords from pre-determined web browsers
  • update - Update the malware script
  • uninstall - Uninstall the malware from the machine
  • up-n-exec - Download and execute a file from a pre-determined URL
  • bring-log - Upload WSH logs
  • down-n-exec - Download and execute a file from the given URL
  • filemanager - Download and execute fm-plugin.exe
  • rdp - Download and execute rd-plugin.exe used for keylogging
  • rev-proxy - Drop and execute rprox.exe used for reverse proxy
  • exit-proxy - Terminate rprox.exe
  • exit-hrdp - Terminate hrdp.exe
  • keylogger - Drop and execute kl-plugin.exe used for keylogging
  • offline-keylogger - Drop and execute kl-plugin.exe used for keylogging
  • browse-logs - Upload list of logs
  • cmd-shell - Execute sent shell command
  • get-processes - Sends list of running processes
  • disable-uac - Disable security
  • check-eligible - Check if a file exists
  • rev-rdp - Download and execute rdp
  • force-eligible - Check if a file exists then execute it
  • elevate - Elevate malware administrative rights
  • if-elevate - Check if malware has administrative rights
  • kill-process - Terminate a specific process
  • sleep - The malware sleeps for a given amount of time
  • update - Update the malware script

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

  • danielmasonyachtsale.{BLOCKED}s.org

Information Theft

This Worm gathers the following data:

  • Computer Name
  • User Name
  • Operating System
  • AV Products
  • Machine's Country
  • Disk Volume Serial Number
  • User Credentials

It logs a user's keystrokes to steal information.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.704.04

FIRST VSAPI PATTERN DATE:

24 Feb 2020

VSAPI OPR PATTERN File:

15.705.00

VSAPI OPR PATTERN Date:

25 Feb 2020

Step 1

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 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

Identify and terminate files detected as Worm.WSF.DUNIHI.PAT

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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_LOCAL_MACHINE\SOFTWARE\{Malware Name}
    • (Default) = {true or false} - {Date of infection}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\Currentversion\Run
    • {Malware Name} = wscript.exe //B %Application Data%\{Malware Name}.wsf
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Currentversion\Run
    • {Malware Name} = wscript.exe //B %Application Data%\{Malware Name}.wsf

Step 5

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
    • From: EnableLUA = 0
      To: EnableLUA = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
    • From: ConsentPromptBehaviorAdmin = 0
      To: ConsentPromptBehaviorAdmin = 3
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
    • From: DisableAntiSpyware = 1
      To: DisableAntiSpyware = 0

Step 6

Search and delete these files

[ 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.
  • %User Temp%\ebgeaegdbdecaedfebace.reg
  • %Application Data%\{Malware Name}.wsf
  • %User Startup%\{Malware Name}.wsf
  • {Removable Drive}\{Malware Name}.wsf

Step 7

Scan your computer with your Trend Micro product to delete files detected as Worm.WSF.DUNIHI.PAT. 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 the following Trend Micro Support pages for more information:


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