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Ransom.Win64.FUNKSEC.THAOFBE

February 11, 2025
 Analysis by: Raighen Sanchez
 ALIASES:

Ransom:Win64/FunkSec!rfn (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It downloads a file from a certain URL then renames it before storing it in the affected system.

However, as of this writing, the said sites are inaccessible.

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

5,482,496 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

06 Jan 2025

Payload:

Connects to URLs/IPs, Drops files, Modifies system registry, Terminates processes, Encrypts files

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • {malware filepath}\downloaded_wallpaper.jpg → desktop wallpaper after encryption

It adds the following processes:

  • %System%\net.exe
  • %System%\tasklist.exe /fi "IMAGENAME eq vmware"
  • powershell -Command Set-MpPreference -DisableRealtimeMonitoring $true
  • powershell -Command wevtutil sl Security /e:false
  • powershell -Command Set-ExecutionPolicy Bypass -Scope Process -Force
  • vssadmin delete shadows /all /quiet

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

Other System Modifications

This Ransomware sets the system's desktop wallpaper to the following image:

Process Termination

This Ransomware terminates the following services if found on the affected system:

  • wuauserv
  • bits
  • Spooler
  • DockApp
  • MpsSvc
  • XblGameSave
  • DiagTrack
  • SysMain
  • lfsvc
  • seclogon
  • wscsvc
  • trkwks
  • RemoteRegistry
  • netprofm
  • Netsh
  • twinapi.appcore
  • TimeBrokerSvc
  • RasMan
  • sshd
  • LanmanWorkstation
  • CryptSvc
  • EventLog
  • WinDefend

It terminates the following processes if found running in the affected system's memory:

  • chrome.exe
  • firefox.exe
  • explorer.exe
  • outlook.exe
  • spotify.exe
  • vlc.exe
  • skype.exe
  • teams.exe
  • discord.exe
  • java.exe
  • python.exe
  • node.exe
  • javaw.exe
  • winword.exe
  • excel.exe
  • powerpnt.exe
  • cmd.exe
  • powershell.exe
  • notepad++.exe
  • gimp-2.10.exe
  • photoshop.exe
  • iTunes.exe
  • system32.exe

Download Routine

This Ransomware downloads files from the following URLs then renames them before storage in the affected system:

  • https://{BLOCKED}r.com/HCYQoVR.jpeg → desktop wallpaper after encryption

Other Details

This Ransomware does the following:

  • It checks for the presence of the following virtual environment-related strings in the system:
    • vboxservice
    • qemu
    • hyperv
    • vmware

However, as of this writing, the said sites are inaccessible.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • txt
  • csv
  • docx
  • xlsx
  • pdf
  • json
  • xml
  • sql
  • log
  • html
  • css
  • js
  • php
  • py
  • java
  • c
  • cpp
  • sh
  • bat
  • ini
  • yaml
  • md
  • rtf
  • ts
  • jsx
  • tsx
  • pptx
  • odt
  • ods
  • odp
  • msg
  • eml
  • apk
  • ipa
  • exe
  • dll
  • dmg
  • iso
  • vmdk
  • vhd
  • tgz
  • 7z
  • zip
  • tar
  • rar
  • bak
  • db
  • mdb
  • sqlite
  • hdf5
  • parquet
  • avro
  • etl
  • pfx
  • cer
  • pem
  • csr
  • key
  • pgp
  • kdbx
  • gpg
  • tar.gz
  • xz
  • dbf
  • tiff
  • raw
  • ai
  • psd
  • indd
  • eps
  • svg
  • dwg
  • dxf
  • fla
  • flv
  • mov
  • mp4
  • avi
  • mkv
  • mp3
  • wav
  • flac
  • aac
  • ogg
  • wma
  • webm
  • m3u
  • cue
  • midi
  • ps
  • tex
  • bib
  • chm
  • epub
  • azw3
  • fb2
  • djvu
  • opf
  • xps
  • jar
  • war
  • ear
  • pdb
  • msi
  • deb
  • rpm
  • vcs
  • git
  • svn
  • nfs
  • bin
  • bkp
  • lst
  • dat
  • png

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

  • {original filename}.{original extension}.funksec

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

  • {malware filepath}\README-{10 random alphanumeric}.md

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.830.05

FIRST VSAPI PATTERN DATE:

10 Jan 2025

VSAPI OPR PATTERN File:

19.831.00

VSAPI OPR PATTERN Date:

11 Jan 2025

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:

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.
  • {malware filepath}\downloaded_wallpaper.jpg
  • {malware filepath}\README-{10 random alphanumeric}.md

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win64.FUNKSEC.THAOFBE. 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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