Analysis by: John Rainier Navato

ALIASES:

Trojan.Win32.Crypt

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Trojan 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: 463,872 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 01 Nov 2023
Payload: Drops files, Modifies system registry, Creates files

Arrival Details

This Trojan 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 Trojan adds the following processes:

  • cmd.exe /c ping 0 -n 20 & schtasks /create /sc minute /mo 2 /tn "Proxifier" /tr "%All Users Profile%\Proxifier\IncrediBuild\SysSettings64.exe"
  • cmd.exe /c ping 0 -n 4 & del %System%\rundll32.exe SolidPDFCreator.dll /f

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). . %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It creates the following folders:

  • %All Users Profile%\Profixier
  • %All Users Profile%\Profixier\IncrediBuild
  • %All Users Profile%\Downloads

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

Autostart Technique

This Trojan creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Profixier = %All Users Profile%\Profixier\IncrediBuild\SysSettings64.exe

Dropping Routine

This Trojan drops the following files:

  • %All Users Profile%\Profixier\IncrediBuild\Solid PDF Creator.dll
  • %All Users Profile%\Profixier\IncrediBuild\SysSettings64.exe

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

Other Details

This Trojan does the following:

  • It sets the following folders' attribute to Hidden:
    • %All Users Profile%\Profixier
    • %All Users Profile%\Profixier\IncrediBuild
  • It adds the following event to ensure that only one of its copies run at any one time:
    • gasdfsdf
  • It loads and decrypts the following files:
    • {Malware File Path}\~$陳彥齊.docx → decrypted and dropped as %All Users Profile%\Profixier\IncrediBuild\SysSettings64.exe
    • {Malware File Path}\~$簡歷_短版.docx→ decrypted and dropped as %All Users Profile%\Profixier\IncrediBuild\Solid PDF Creator.dll
  • It creates the following scheduled task:
    • Name: Profixier
    • Action: %All Users Profile%\Proxifier\IncrediBuild\SysSettings64.exe
    • Trigger: At {Scheduled Task Create Time} - After triggered, repeat every 00:02:00 indefinitely.
  • It deletes itself and the file used to execute the trojan after execution.

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.814.03
FIRST VSAPI PATTERN DATE: 12 Nov 2023
VSAPI OPR PATTERN File: 18.815.00
VSAPI OPR PATTERN Date: 13 Nov 2023

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.XXPE50FFF074

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

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

Deleting Scheduled Tasks while in Safe Mode

  1. Still in safe mode, the following {Task Name}-{Task to be run} listed should be used in the steps identified below:
    • Task Name: Profixier
    • Task to be run:%All Users Profile%\Proxifier\IncrediBuild\SysSettings64.exe
  2. For Windows 7 and Server 2008 (R2) users, click Start>Computer.
    • For Windows 8, 8.1, 10, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
  3. In the Search Computer/This PC input box, type:
    • %System%\Tasks\{Task Name}
  4. Once located, select the file then press SHIFT+DELETE to delete it.
  5. Open Registry Editor. To do this:
    • For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field, and press Enter.
    • For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box
  6. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  7. Locate the created entry and take note of the registry value's data:
    • ID={Task Data}
  8. After taking note of the data, delete the registry key:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  9. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tasks
  10. Still in the left panel, locate and delete the registry key with the same name as the located Task Data in step #6:
    • ={Task Data}
  11. Close Registry Editor.

Step 6

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
    • Profixier = %All Users Profile%\Profixier\IncrediBuild\SysSettings64.exe

Step 7

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.
  • {Malware File Path}\$陳彥齊.docx
  • {Malware File Path}\~$簡歷_短版.docx
  • %All Users Profile%\Profixier\IncrediBuild\SysSettings64.exe
  • %All Users Profile%\Profixier\IncrediBuild\Solid PDF Creator.dll

Step 8

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden folders in the search result.
  • %All Users Profile%\Profixier
  • %All Users Profile%\Profixier\IncrediBuild
  • %All Users Profile%\Downloads

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.Win32.TONEINS.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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