Trojan.JS.DUNIHI.AMX
TrojanDownloader:JS/Obfuse.PRWA (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.
TECHNICAL DETAILS
357,402 bytes
JS
No
04 Jun 2023
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 files:
- %Application Data%\[Random characters].txt
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It adds the following processes:
- {JRE Directory}\bin\javaw.exe -jar %Application Data%\[Random characters].txt → if JRE is installed
- %Application Data%\jre7\bin\javaw.exe -jar %Application Data%\[Random characters].txt → if JRE is NOT installed
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ntfsmgr = %Application Data%\jre7\bin\javaw.exe -jar %Application Data%\[Random characters].txt → if JRE is NOT installed
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.
Information Theft
This Trojan does not have any information-stealing capability.
Other Details
This Trojan does the following:
- checks if system has Java Runtime Environment (JRE) installed so it could run dropped malicious file (%Application Data%\ntfsmgr.jar) by reading the following registries:
- HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\JavaSoft\Java Runtime Environment\{JRE Version}\JavaHome
- HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment\{JRE Version}\JavaHome
- if JRE is not yet installed, it does the following:
- downloads JRE archive from URL:
- http://{BLOCKED}t.company/jv/jree.zip
- saves file as:
- %Application Data%\jre.zip
- decompresses it to:
- %Application Data%\jre7
SOLUTION
9.800
18.490.04
05 Jun 2023
18.491.00
06 Jun 2023
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.XXJSE9EFF047
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
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
- ntfsmgr = "%Application Data%\jre7\bin\javaw.exe" -jar "%Application Data%\[Random characters].txt"
- ntfsmgr = "%Application Data%\jre7\bin\javaw.exe" -jar "%Application Data%\[Random characters].txt"
Step 5
Search and delete this folder
- %Application Data%\jre7
Step 6
Search and delete these files
- %Application Data%\jre.zip
- %Application Data%\[Random characters].txt
Step 7
Scan your computer with your Trend Micro product to delete files detected as Trojan.JS.DUNIHI.AMX. 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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