Trojan.JS.EMANSREPO.A
Trojan:JS/MalScript!MSR (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.
As of this writing, the said sites are inaccessible.
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:
- powershell -NoProfile -WindowStyle Hidden -ExecutionPolicy Bypass -File "%User Temp%\script.ps1"
(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).)
Download Routine
This Trojan connects to the following website(s) to download and execute a malicious file:
- http://{BLOCKED}.{BLOCKED}.{BLOCKED}.185/script.ps1
It saves the files it downloads using the following names:
- %User Temp%\script.ps1 → detected as Trojan.PS1.EMANSREPO.A
As of this writing, the said sites are inaccessible.
Other Details
This Trojan does the following:
- It checks if %User Temp%\script.ps1 exists.
- If not, it connects to http://{BLCOKED}.{BLOCKED}.{BLOCKED}.185/script.ps1 to download a malicious script, save it as %User Temp%\script.ps1, and execute it.
- If it exists, it terminates itself
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:
- Downloader.JS.TRX.XXJSE9EFF062
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
Search and delete this file
- %User Temp%\script.ps1
Step 5
Scan your computer with your Trend Micro product to delete files detected as Trojan.JS.EMANSREPO.A. 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 the following Trend Micro Support pages for more information:
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