TROJ_MSIL.BLM
Windows
![](/vinfo/imgFiles/legend.jpg)
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
728,576 bytes
EXE
No
11 Oct 2015
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:
- %User Profile%\Windows\dnsmon.exe
(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.)
It creates the following folders:
- %System Root%\Documents and Settings\Wilbert
- %User Profile%\Microsoft\CLR Security Config
- %User Profile%\CLR Security Config\v2.0.50727.42
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.)
Other System Modifications
This Trojan deletes the following files:
- {malware path and file name}a
- %User Profile%\Windows\natsv.exeA
- %User Profile%\Windows\dnsmon.exeA
- %User Profile%\Windows\dnsmon.exe
(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.)
Dropping Routine
This Trojan drops the following files:
- %User Profile%\Windows\natsv.exe
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.new
- %User Profile%\v2.0.50727.42\security.config.cch.new
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.new
(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.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
This report is generated via an automated analysis system.
SOLUTION
9.750
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
Search and delete these components
- %User Profile%\Windows\natsv.exe
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.new
- %User Profile%\v2.0.50727.42\security.config.cch.new
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.new
Step 3
Search and delete these folders
- %System Root%\Documents and Settings\Wilbert
- %User Profile%\Microsoft\CLR Security Config
- %User Profile%\CLR Security Config\v2.0.50727.42
Step 4
Scan your computer with your Trend Micro product to delete files detected as TROJ_MSIL.BLM. 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.
Step 5
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- {malware path and file name}a
- %User Profile%\Windows\natsv.exeA
- %User Profile%\Windows\dnsmon.exeA
- %User Profile%\Windows\dnsmon.exe
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