Analysis by: Melvin Jhun Palbusa
ALIASES:

Ransom:Win32/IncRansom.YAA!MTB (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Ransomware drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 143,360 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 05 Sep 2023
Payload: Encrypts files, Displays graphics/image, Modifies system registry

Installation

This Ransomware drops the following files:

  • %User Temp%\background-image.jpg
  • %System%\spool\PRINTERS\00002.SPL
  • %System%\spool\PRINTERS\00002.SHD

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

Other System Modifications

This Ransomware modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
(Default) = %System%\imageres.dll,-55

(Note: The default value data of the said registry entry is %System%\imageres.dll,-54.)

It changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_UESR\Control Panel\Desktop
Wallpaper = %User Temp%\background-image.jpg

Other Details

This Ransomware does the following:

  • Empty Recycled Bin
  • It enumerates printers in the network to print the ransom note.
  • It encrypts fixed, removable, and network drives.

It accepts the following parameters:

  • --file {File Path} → Encrypts the specified file.
  • --dir {Directory Path} → Encrypts the specified directory.
  • --ens → Enumerates available network shares to encrypt.
  • --lhd → Encrypt hidden drives.
  • --sup → Uses the Windows Restart Manager API to close processes or shut down Windows services that may be keeping a file open and preventing encryption.
  • --debug → Displays logs within the command prompt

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file path:

  • windows
  • Program files
  • Program files (x86)
  • $RECYCLE.BIN
  • appdata

It appends the following extension to the file name of the encrypted files:

  • {original file name}.{original extension}.INC

It drops the following file(s) as ransom note:

  • {Encrypted Directory}\INC-README.html
  • {Encrypted Directory}\INC-README.txt

It avoids encrypting files with the following file extensions:

  • .exe
  • .msi
  • .dll
  • .inc

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.918.02
FIRST VSAPI PATTERN DATE: 03 Jan 2024
VSAPI OPR PATTERN File: 18.919.00
VSAPI OPR PATTERN Date: 04 Jan 2024

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.XXPE50FFF073

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

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.
  • %User Temp%\background-image.jpg
  • %System%\spool\PRINTERS\00002.SPL
  • %System%\spool\PRINTERS\00002.SHD
  • {Encrypted Directory}\INC-README.html
  • Encrypted Directory}\INC-README.txt

Step 5

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{645FF040-5081-101B-9F08-00AA002F954E}\DefaultIcon
    • (Default) = %System%\imageres.dll,-55

Step 6

Reset your Desktop properties

[ Learn More ]

Step 7

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.RANINC.AC. 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:

Step 8

Restore encrypted files from backup.


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