Ransom_SCARAB.G
Ransom:Win32/Kitoles.A (Microsoft)
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted:
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 is capable of encrypting files in the affected system.
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 copies of itself into the affected system:
- %Application Data%\osk.exe
(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)
It adds the following processes:
- "C:\Windows\system32\cmd.exe" /c copy /y "C:\Users\dyituser_732\Downloads\{Malware File Name}.exe" "%Application Data%\osk.exe";
- mshta.exe "javascript:o=new ActiveXObject('Scripting.FileSystemObject');setInterval(function(){try{o.DeleteFile('{Malware File Name}.exe');close()}catch(e){}},10);"
- mshta.exe "javascript:o=new ActiveXObject('WScript.Shell');x=new ActiveXObject('Scripting.FileSystemObject');setInterval(function(){try{i=x.GetFile('osk.exe').Path;o.RegWrite('HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce\{Random Name}',i);}catch(e){}},10);"
- mshta.exe "javascript:eval(new ActiveXObject('WScript.Shell').RegRead('HKCU\Software\{Random Name}\E[XTS'));close();"
- "C:\Windows\System32\cmd.exe" /c wbadmin DELETE SYSTEMSTATEBACKUP -keepVersions:0
- "C:\Windows\System32\cmd.exe" /c wmic SHADOWCOPY DELETE
- "C:\Windows\System32\cmd.exe" /c vssadmin Delete Shadows /All /Quiet
- "C:\Windows\System32\cmd.exe" /c bcdedit /set {default} recoveryenabled No
- "C:\Windows\System32\cmd.exe" /c bcdedit /set {default} bootstatuspolicy ignoreallfailures
- wbadmin DELETE SYSTEMSTATEBACKUP -keepVersions:0
- C:\Windows\System32\cmd.exe;new process;vssadmin Delete Shadows /All /Quiet
- C:\Windows\System32\cmd.exe;new process;wmic SHADOWCOPY DELETE
- C:\Windows\System32\cmd.exe;new process;bcdedit /set {default} recoveryenabled No
- C:\Windows\System32\cmd.exe;new process;bcdedit /set {default} bootstatuspolicy ignoreallfailures
(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)
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\RunOnce
TScZfk = %Application Data%\osk.exe
Other System Modifications
This Ransomware adds the following registry keys:
HKEY_CURRENT_USER\Software\{Random Letters}
HKEY_CURRENT_USER\Software\TScZfk
Other Details
This Ransomware is capable of encrypting files in the affected system.
Ransomware Routine
This Ransomware renames encrypted files using the following names:
- {Location of Encrypted File}\{Encrypted Filename}.amnesia
It drops the following file(s) as ransom note:
- {Location of Encrypted File}\??? ???????????? ?? ?? ?????? ?????.TXT
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 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
Restart in Safe Mode
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_CURRENT_USER\Software
- TScZfk
- TScZfk
- In HKEY_CURRENT_USER\Software
- {Random Letters}
- {Random Letters}
Step 5
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
- TScZfk = %Application Data%\osk.exe
- TScZfk = %Application Data%\osk.exe
Step 6
Search and delete these files
- {Location of encrypted file}\??? ???????????? ?? ?? ?????? ?????.TXT
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom_SCARAB.G. 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 8
Restore encrypted files from backup.
NOTES:
Enable Windows Recovery Option:
- Run cmd.exe as administrator.
- Type bcdedit /set {default} recoveryenabled yes then press Enter.
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