Analysis by: Leidryn Saludez
ALIASES:

HEUR:Trojan-Ransom.MSIL.Blocker.gen (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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: 89,475,072 bytes
File Type: EXE
Initial Samples Received Date: 18 Mar 2025
Payload: Drops files, Modifies system registry

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 drops the following files:

  • %Application Data%\apps .dat → Deleted afterwards
  • %Application Data%\apps.exe
  • %Application Data%\SoundCloud .dat → Deleted afterwards
  • %Application Data%\SoundCloud.exe
  • %User Temp%\{Malware Name} .docx → Deleted afterwards
  • {Malware Path}\{Malware Name}.docx
  • %Application Data%\Microsoft\Office\MSO1033.acl
  • %Application Data%\Microsoft\Document Building Blocks\1033\Building Blocks.dotx
  • %User Temp%\mso8BDD.tmp
  • %Application Data%\Microsoft\Office\Recent\{Malware Name}.docx.LNK
  • %Application Data%\Microsoft\Office\Recent\{Malware Path}.LNK

(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).. %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:

  • "C:\Windows\system32\cmd.exe" /C ping 1.1.1.1 -w 500 -n 2 > nul & attrib -r -a -s -h "{Malware Path}\{Malware Name}.exe" & del "{Malware Path}\{Malware Name}.exe" & certutil -f -decode "%User Temp%\{Malware Name}.docx" "{Malware Path}\{Malware Name}.docx" & del "%User Temp%\{Malware Name}.docx" & "{Malware Path}\{Malware Name}.docx"
  • ping 1.1.1.1 -w 500 -n 2
  • attrib -r -a -s -h "{Malware Path}\{Malware Name}.exe"
  • certutil -f -decode "%User Temp%\{Malware Name} .docx" "{Malware Path}\{Malware Name} .docx"
  • "%Program Files%\Microsoft Office\Office12\WINWORD.EXE" /n /dde

(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).. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Apps = "%Application Data%\apps.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
SoundCloud = "%Application Data%\SoundCloud.exe"

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.936.54
FIRST VSAPI PATTERN DATE: 04 Mar 2025
VSAPI OPR PATTERN File: 19.937.00
VSAPI OPR PATTERN Date: 05 Mar 2025

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

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.  
  • %Application Data%\apps.exe
  • %Application Data%\SoundCloud.exe
  • {Malware Path}\{Malware Name}.docx
  • %Application Data%\Microsoft\Office\MSO1033.acl
  • %Application Data%\Microsoft\Document Building Blocks\1033\Building Blocks.dotx
  • %User Temp%\mso8BDD.tmp
  • %Application Data%\Microsoft\Office\Recent\{Malware Name}.docx.LNK
  • %Application Data%\Microsoft\Office\Recent\{Malware Path}.LNK

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
    • Apps = %Application Data%\apps.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • SoundCloud = %Application Data%\SoundCloud.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.MSIL.BUBLIK.C. 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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