Win32:DangerousSig [Trj] (AVAST)
Windows
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.
However, as of this writing, the said sites are inaccessible.
It drops files as ransom note. It avoids encrypting files with the following file extensions.
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:
(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )
It adds the following processes:
It adds the following mutexes to ensure that only one of its copies runs at any one time:
Other System Modifications
This Ransomware adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.{Generated Extension}
(Default) = {Generated Extension}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
{Generated Extension}\DefaultIcon
(Default) = %All Users Profile%\{Generated Extension}.ico
It changes the desktop wallpaper by modifying the following registry entries:
HKEY_USERS\{USER SID}\Control Panel\
Desktop
Wallpaper = %All Users Profile%\{Generated Extension}.BMP
HKEY_USERS\{USER SID}\Control Panel\
Desktop
WallpaperStyle = 10
It sets the system's desktop wallpaper to the following image:
Process Termination
This Ransomware terminates the following services if found on the affected system:
It terminates the following processes if found running in the affected system's memory:
Information Theft
This Ransomware gathers the following data:
Stolen Information
This Ransomware sends the gathered information via HTTP POST to the following URL:
Other Details
This Ransomware adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.{Generated Extension}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
{Generated Extension}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
{Generated Extension}\DefaultIcon
It does the following:
However, as of this writing, the said sites are inaccessible.
Ransomware Routine
This Ransomware avoids encrypting files with the following strings in their file name:
It avoids encrypting files with the following strings in their file path:
It appends the following extension to the file name of the encrypted files:
It drops the following file(s) as ransom note:
It avoids encrypting files with the following file extensions:
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:
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
Step 5
Identify and terminate files detected as Ransom.Win32.DARKSIDE.FAIO
Step 6
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.
Step 7
Search and delete this file
Step 8
Reset your Desktop properties
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.DARKSIDE.FAIO. 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 10
Restore encrypted files from backup.