Trojan.Win32.ZARLOADR.A
Windows
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Threat Type: Trojan
Destructiveness: No
Encrypted:
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.
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 drops the following files:
- %System%\oci.dll → malicious oci.dll detected as Trojan.Win32.ZARLOADR.B
- %User Temp%\win_oci_41aa0d5.dll → If the service msdtc failed to stop. Delete after being executed.
- %User Temp%\xz330ksdfg.bat → batch file to delete itself and this batch file
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %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).)
It adds the following processes:
- cmd /c %User Temp%\xz330ksdfg.bat
- rundll32.exe %User Temp%\win_oci_41aa0d5.dll MainEntry → if failed to stop msdtc service
(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).)
Other Details
This Trojan does the following:
- Checks if the msdtc service is present:
- If not present:
- Adds the following process:
- msdtc -install
- If present:
- Stop the service then start it again to load the malicious oci.dll
- If the service is present but failed to stop:
- Drops the file:
- %Temp%\win_oci_41aa0d5.dll --> Delete after execution
(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)
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.XXPE50FFF078
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
- %System%\oci.dll → Malicious oci.dll
Step 5
Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.ZARLOADR.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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