Ransom:Win32/Tescrypt.A (Microsoft), RDN/TeslaCrypt (McAfee), Trojan.Cryptolocker.N (Symantec)
Windows
This Trojan 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. It deletes the initially executed copy of itself.
Arrival Details
This Trojan 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 Trojan drops the following copies of itself into the affected system and executes them:
(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.)
It drops the following files:
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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 Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
ms-helper = "%Application Data%\vcw{random letters}.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
ms-helper = "%Application Data%\vcw{random letters}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\msys
HKEY_CURRENT_USER\Software\{installation ID}
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnabledLinkConnections = 1
HKEY_CURRENT_USER\Software\{installation ID}
data = {encryption information}
HKEY_CURRENT_USER\Software\msys
ID = {installation ID}
Process Termination
This Trojan terminates processes or services that contain any of the following strings if found running in the affected system's memory:
Information Theft
This Trojan gathers the following data:
Other Details
This Trojan connects to the following URL(s) to get the affected system's IP address:
It connects to the following website to send and receive information:
It encrypts files with the following extensions:
It deletes the initially executed copy of itself
NOTES:
It appends the extension .abc to the filename of the encrypted files.
It drops restore_files_{random 5 letters 2}.html and restore_files_{random 5 letters 2}.txt to all directories it traversed in searching for files to encrypt.
Here are the screenshot of its ransom note (in HTML and TXT) showing instructions on how to restore the encrypted files by paying in Bitcoin via their onion payment sites.
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
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.
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.
Step 5
Search and delete these files
Step 6
Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYPTESLA.JE. 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.
NOTES:
Restore the encrypted files from backup.