Trojan.Win64.DOWNLOADER.NLJ
Trojan:Win32/Casdet!rfn (MICROSOFT)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
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 does not have any propagation routine.
It does not have any backdoor routine.
It does not have any information-stealing capability.
It connects to certain websites to send and receive information.
TECHNICAL DETAILS
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 adds the following processes:
- %User Profile%\Pictures\{24 Random Alphanumeric Characters}.exe {Arguments} → executes the downloaded files.
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It stays resident in memory by creating the following process(es):
- %Windows%\{Microsoft .NET Directory}\AddInProcess32.exe
- %Windows%\{Microsoft .NET Directory}\CasPol.exe
- %Windows%\{Microsoft .NET Directory}\jsc.exe
- %Windows%\{Microsoft .NET Directory}\MSBuild.exe
- %Windows%\{Microsoft .NET Directory}\RegAsm.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
Autostart Technique
This Trojan drops the following files:
- %User Startup%\{24 Random Alphanumeric Characters}.bat → drops multiple times based on the number of downloaded files.
- which contains the following code:
- start "" "%AppDataLocal%\{24 Random Alphanumeric Characters}.exe {Arguments}
- which contains the following code:
(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
Propagation
This Trojan does not have any propagation routine.
Backdoor Routine
This Trojan does not have any backdoor routine.
Rootkit Capabilities
This Trojan does not have rootkit capabilities.
Download Routine
This Trojan connects to the following website(s) to download and execute a malicious file:
- https://{BLOCKED}p.su/RNWPd.exe → as of this writing, the site is already inaccessible.
- https://{BLOCKED}bin.com/raw/E0rY26ni
- which contains the following URLs used to download other malicious files:
- http://{BLOCKED}.{BLOCKED}.{BLOCKED}.59/ISetup5.exe → detected as TrojanSpy.Win32.STEALC.E
- http://{BLOCKED}.{BLOCKED}.{BLOCKED}.175/server/ww12/AppGate2103v01.exe
- http://{BLOCKED}.{BLOCKED}.{BLOCKED}.17/files/001MX.exe
- http://{BLOCKED}.{BLOCKED}.{BLOCKED}.17/files/setup.exe
- http://{BLOCKED}.{BLOCKED}.{BLOCKED}.17/files/InstallCharityEngine_7.14.2_S16-01.exe
- http://{BLOCKED}era.com/opera/stable/windows/?utm_medium=apb&utm_source=mkt&utm_campaign=767__456
- https://{BLOCKED}epai.org/6779d89b7a368f4f3f340b50a9d18d71.exe
- https://{BLOCKED}irls.org/baf14778c246e15550645e30ba78ce1c.exe → as of this writing, the site is already inaccessible.
- which contains the following URLs used to download other malicious files:
It saves the files it downloads using the following names:
- %AppDataLocal%\{24 Random Alphanumeric Characters}.exe
- %User Profile%\Pictures\{24 Random Alphanumeric Characters}.exe
(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
Information Theft
This Trojan does not have any information-stealing capability.
Other Details
This Trojan connects to the following website to send and receive information:
- https://{BLOCKED}ger.com/1lyxz
SOLUTION
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:
- Troj.Win32.TRX.XXPE50FFF079
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
Search and delete these files
- %AppDataLocal%\{24 Random Alphanumeric Characters}.exe
- %User Profile%\Pictures\{24 Random Alphanumeric Characters}.exe
- %User Startup%\{24 Random Alphanumeric Characters}.bat
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.Win64.DOWNLOADER.NLJ. 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.
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