RANSOM_CRYPSHED.THDAH
Ransom.Troldesh(Malwarebytes)
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 connects to certain websites to send and receive information.
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:
- %Application Data%{random filename}.bmp - set as desktop wallpaper
- {Drive Letter}:\README{1-9}.txt - ransom note
- %Desktop%\README{1-9}.txt - ransom note
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This Ransomware modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Client Server Runtime Subsytem = %All Users Profile%Windows\csrss.exe
Other System Modifications
This Ransomware adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
shsnt = 1
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
shst = 1
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xcnt = {number of encrypted files}
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xi = {ID}
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xmode = 0
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xpk = {Public Key}
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xstate = 4
HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xVersion = 4.0.0.1
It adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\Software\System32\
Configuration
It sets the system's desktop wallpaper to the following image:
Other Details
This Ransomware connects to the following URL(s) to get the affected system's IP address:
- whatismyipaddress.com
- whatsmyip.net
It connects to the following website to send and receive information:
- http://{BLOCKED}p2xzclh6fd.onion/sys.php
- http://{BLOCKED}p2xzclh6fd.onion/reg.php
- http://{BLOCKED}p2xzclh6fd.onion/prog.php
- http://{BLOCKED}p2xzclh6fd.onion/err.php
- http://{BLOCKED}p2xzclh6fd.onion/cmd.php
It renames encrypted files using the following names:
- {unique_id}.{identifier}.no_more_ransom
It sets the attributes of the following file(s) to Hidden and System:
- %ProgramData%\Windows
(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It does the following:
- Installs TOR browser
- This ransomware deletes all shadow copies by executing the following command:
- vssadmin Delete Shadows /All /Quiet
NOTES:
The ransom note contains the following:
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_LOCAL_MACHINE\Software\System32
- Configuration
- Configuration
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\Run
- Client Server Runtime Subsytem = %All Users Profile%Windows\csrss.exe
- Client Server Runtime Subsytem = %All Users Profile%Windows\csrss.exe
Step 6
Search and delete this file
- %Application Data%{random filename}.bmp
- {Drive Letter}:\README{1-9}.txt
- %Desktop%\README{1-9}.txt
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_CRYPSHED.THDAH. 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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