Ransom.Win32.SODINOKIBI.AUWSV
Trojan:Win32/Tiggre!rfn(Microsoft); Trojan.Win32.DelShad.cu(Kaspersky)
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 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%\{random characters}.bmp
- {encrypted folder}\{random characters}.lock
- {encrypted folder}\{appended ransom extension}-readme.txt
(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:
- vssadmin.exe Delete Shadows /All /Quiet
- bcdedit /set {default} recoveryenabled No
- bcdedit /set {default} bootstatuspolicy ignoreallfailures
Other System Modifications
This Ransomware adds the following registry keys:
HKEY_CURRENT_USER\Software\recfg
pk_key = {hex value}
HKEY_CURRENT_USER\Software\recfg
sk_key = {hex value}
HKEY_CURRENT_USER\Software\recfg
0_key = {hex value}
HKEY_CURRENT_USER\Software\recfg
rnd_ext = {random characters}
HKEY_CURRENT_USER\Software\recfg
stat = {hex value}
It changes the desktop wallpaper by modifying the following registry entries:
HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\{random characters}.bmp
Ransomware Routine
This Ransomware appends the following extension to the file name of the encrypted files:
- .{random characters}
It drops the following file(s) as ransom note:
- {encrypted folder}\{appended ransom extension}-readme.txt
SOLUTION
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
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.
- HKEY_CURRENT_USER\Software\recfg
Step 5
Search and delete this file
- {encrypted folder}\{random characters}.lock
- {encrypted folder}\{appended ransom extension}-readme.txt
- %User Temp%\{random characters}.bmp
Step 6
Reset your Desktop properties
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.SODINOKIBI.AUWSV. 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.
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