Ransom.Win64.MEDUSALOCKER.THIBGBD


 ALIASES:

Gen:Variant.Ransom.MedusaLocker.65 (BITDEFENDER)

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

  TECHNICAL DETAILS

File Size:

431,616 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Sep 2023

Payload:

Modifies system registry, Terminates processes, Disables AV, 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 adds the following processes:

  • By using the command line "\?\%Windows%\SysWOW64\cmd.exe /c %Windows%\sysnative\cmd.exe /c {Commands Below}:
    • rem Kill \"SQL\"
    • vssadmin.exe Delete Shadows /All /Quiet
    • wbadmin delete backup -keepVersion:0 -quiet
    • wbadminDELETE SYSTEMSTATEBACKUP
    • wbadmin DELETE SYSTEMSTABACKUP -deleteOldest
    • wmic.exe SHADOWCOPY /nointeractive
    • bcdedit.exe /set {default} recoverynabled No
    • bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures
    • net stop {Target Services}
    • taskkill -f -im {Target Processes}
  • cipher /w:\?\{Drive Letter}
  • %System%\cmd.exe /c pause

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
BabyLockerKZ = {Malware Path}\{Malware File Name}.exe

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\PAIDMEMES
PUBLIC = {Ransomware Public Key}

HKEY_CURRENT_USER\Software\PAIDMEMES
PRIVATE = {Ransomware Private Key}

Process Termination

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

  • Via net stop:
    • MSSQLServerADHelper100
    • MSSQL$ISARS
    • MSSQL$MSFW
    • SQLAgent$ISARS
    • SQLAgent$MSFW
    • SQLBrowser
    • REportServer$ISARS
    • SQLWriter

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

  • Via taskkill -f -im:
    • sqlbrowser.exe
    • sql writer.exe
    • sqlserv.exe
    • msmdsrv.exe
    • MsDtsSrvr.exe
    • sqlceip.exe
    • fdlauncher.exe
    • Ssms.exe
    • SQLAGENT.EXE
    • fdhost.exe
    • ReportingServicesService.exe
    • msftesql.exe
    • pg_ctl.exe
    • postgres.exe

Other Details

This Ransomware adds the following registry keys:

HKEY_CURRENT_USER\Software
PAIDMEMES

It does the following:

  • It encrypts the following drives if found existing on the system:
    • Removable Drive
    • Fixed Drive
    • Remote Drive
    • RAM Disk Drive
  • It attempts to mount unmounted drives before doing encryption.
  • It encrypts data in chunks of 750,016 bytes.
  • It skips encryption of 250,048 bytes of data after every chunks.
  • It encrypts a maximum of 9,633,920 bytes of data for each files.
  • It empties the Recycle Bin.
  • It displays logs using the command line application:

It accepts the following parameters:

  • -network
  • -shares=, -s= {CIDR Notation}
    • Attempts to connect to all the hosts in the network and encrypts all existing drives' files found in each of the hosts.
  • -path=, -p= {Path to Encrypt}
    • Encrypts files found in the given path.

Ransomware Routine

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

  • How_to_back_files.html

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

  • /bin/
  • /etc/
  • /lib/
  • /proc/
  • /sys/
  • /var/
  • /dev/
  • /usr/
  • /tmp/
  • /opt/
  • /etc/
  • \$Recycle.Bin\
  • \Recovery\
  • \Windows\
  • \AppData\
  • \System Volume Information\
  • \Program Files (x86)\
  • \Program Files\
  • \$WinREAgent\
  • \$Windows.~WS\
  • \$WINDOWS.~BT\

It avoids encrypting files found in the following folders:

  • C:\perflogs
  • C:\Intel
  • C:\HP
  • C:\AMD
  • C:\Dell
  • C:\Drivers
  • C:\inetpub
  • B:\Boot
  • A:\Boot
  • B:\EFI
  • A:\EFI
  • C:\ProgramData

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

  • .needhelp266

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

  • {Drive Letter}\How_to_back_files.html
  • %Desktop%\How_to_back_files.html

It avoids encrypting files with the following file extensions:

  • .exe
  • .dll
  • .sys
  • .ini
  • .rdp
  • .lnk
  • .bmp
  • .mov
  • .cab
  • .toml
  • .out
  • .needhelp266

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.616.07

FIRST VSAPI PATTERN DATE:

27 Sep 2024

VSAPI OPR PATTERN File:

19.617.00

VSAPI OPR PATTERN Date:

28 Sep 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.XXPE50FFF085

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

Restart in Safe Mode

[ Learn More ]

Step 5

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
    • BabyLockerKZ = {Malware Path}\{Malware File Name}.exe
  • In HKEY_CURRENT_USER\Software\PAIDMEMES
    • PUBLIC = {Ransomware Public Key}
  • In HKEY_CURRENT_USER\Software\PAIDMEMES
    • PRIVATE = {Ransomware Private Key}

Step 6

Delete this registry key

[ 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\
    • PAIDMEMES

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.
  • {Drive Letter}\How_to_back_files.html
  • %Desktop%\How_to_back_files.html

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win64.MEDUSALOCKER.THIBGBD. 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.

Step 9

Restore encrypted files from backup.


Did this description help? Tell us how we did.