Ransom.Win64.CRYPTWOFOUR.THGOBBE
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
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.
TECHNICAL DETAILS
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:
- %User Temp%\rmsw.bat
- %User Temp%\msin.bat
(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).)
It adds the following processes:
- cmd.exe /c vssadmin delete shadows /all /quiet
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Global\A0:236:Main
Other System Modifications
This Ransomware adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
MSRuntime
D_th{File Count} = 2_{Path To Found File Name}
Other Details
This Ransomware adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
MSRuntime
It does the following:
- Based on code analysis, it may encrypt the following files\files found in the following paths:
- \anydesk\
- \AppData\Local\
- \AppData\LocalLow\
- \AppData\Roaming\
- \Chrome Remote Desktop\
- \ntuser.dat
- \ntuser.ini
- \Program Files\CloudBerryLab\CloudBerry Backup
- \Public\Documents\iconcache.ini
- \Public\Documents\iconcache.log
- \Public\Pictures\log
- %Program Files%
- %Program Files% (x86)
- %Program Files% (x86)\COMODO
- %Program Files% (x86)\Dropbox
- %Program Files% (x86)\Google
- %Program Files% (x86)\Trend Micro
- %Program Files% (x86)\Windows Defender
- %Program Files%(x86)\Kaspersky Lab
- %Program Files%(x86)\Microsoft
- %Program Files%(x86)\Sophos
- %Program Files%(x86)\Symantec
- %Program Files%\AhnLab
- %Program Files%\CloudBerryLab\CloudBerry Backup
- %Program Files%\COMODO
- %Program Files%\Dropbox
- %Program Files%\ESTsoft
- %Program Files%\Google
- %Program Files%\Kaspersky Lab
- %Program Files%\Microsoft
- %Program Files%\Sophos
- %Program Files%\Symantec
- %Program Files%\Trend Micro
- %Program Files%\VMware
- %Program Files%\Windows Defender
- %Program Files%\Windows Defender Advanced Threat Protection
- %Program Files%\WindowsApps
- %ProgramData%
- %ProgramData%\AhnLab
- %ProgramData%\Comodo
- %ProgramData%\Comodo Downloader
- %ProgramData%\Dropbox
- %ProgramData%\ESTsoft
- %ProgramData%\Kaspersky Lab
- %ProgramData%\Microsoft OneDrive
- %ProgramData%\Sophos
- %ProgramData%\ssh
- %ProgramData%\Symantec
- %ProgramData%\Trend Micro
- %ProgramData%\VMware
- %ProgramData%\Windows
- %System Root%\Users
- %System Root%\Users\.N
- %System Root%\users\All Users
- %Windows%
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
Ransomware Routine
This Ransomware avoids encrypting files with the following strings in their file name:
- adm.exe
- rms.bat
- rmsw.bat
- runtimes.exe
- msruntime.dll
- Msruntimes.dll
- rest.bat
- msin.bat
It appends the following extension to the file name of the encrypted files:
- .crypto24
It drops the following file(s) as ransom note:
- {Encrypted File Path}\Decryption.txt
SOLUTION
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.XXPE50FFF095
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
Delete this registry value
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_LOCAL_MACHINE\SOFTWARE\Microsoft\MSRuntime
- D_th{File Count} = 2_{Path To Found File Name}
- D_th{File Count} = 2_{Path To Found File Name}
Step 4
Delete this registry key
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_LOCAL_MACHINE\SOFTWARE\Microsoft
- MSRuntime
- MSRuntime
Step 5
Search and delete these files
- %User Temp%\rmsw.bat
- %User Temp%\msin.bat
- {Encrypted File Path}\Decryption.txt
Step 6
Scan your computer with your Trend Micro product to delete files detected as Ransom.Win64.CRYPTWOFOUR.THGOBBE. 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 7
Restore encrypted files from backup.
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