TrojanSpy.MSIL.REMCOS.A
Windows
Threat Type: Trojan Spy
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan Spy 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 Spy 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 Spy adds the following processes:
- "cmd.exe" /c REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run /f /v console /t REG_SZ /d %System%\pcalua.exe" -a %Application Data%\Microsoft\Windows\Templates\monitorunmgr.exe"
(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 Spy adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
console = "%System%\pcalua.exe -a %Application Data%\Microsoft\Windows\Templates\monitorunmgr.exe"
Other System Modifications
This Trojan Spy deletes the following files:
- %Application Data%\Microsoft\Windows\Templates\monitorunmgr.exe
- {malware file path and name}:Zone.Identifier
(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).)
Dropping Routine
This Trojan Spy drops the following files:
- %Application Data%\Microsoft\Windows\Templates\monitorunmgr.exe
(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).)
This report is generated via an automated analysis system.
SOLUTION
Step 1
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 2
Restart in Safe Mode
Step 3
Identify and terminate files detected as TrojanSpy.MSIL.REMCOS.A
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
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
- console = "%System%\pcalua.exe -a %Application Data%\Microsoft\Windows\Templates\monitorunmgr.exe"
Step 5
Search and delete this file
- %Application Data%\Microsoft\Windows\Templates\monitorunmgr.exe
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TrojanSpy.MSIL.REMCOS.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 this Knowledge Base page for more information.
Step 7
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.
- %Application Data%\Microsoft\Windows\Templates\monitorunmgr.exe
- {malware file path and name}:Zone.Identifier
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