Backdoor.MSIL.REMCOS.JCASJZ
Win32:Malware-gen (AVAST); W32/Remcos.ESOV!tr.bdr (FORTINET)
Windows

Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Backdoor 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
39,845,888 bytes
EXE
No
15 Jan 2021
Arrival Details
This Backdoor 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 Backdoor adds the following folders:
- %Application Data%\remcos
(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 drops the following files:
- %Application Data%\remcos\logs.dat
(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:
- "{malware file path and name}"
Other System Modifications
This Backdoor adds the following registry entries:
HKEY_CURRENT_USER\Software\Remcos-ZHDGID
exepath = {Hex values}
HKEY_CURRENT_USER\Software\Remcos-ZHDGID
licence = 415CD5ADD079B4D70514510C06065D6B
Other Details
This Backdoor adds the following registry keys:
HKEY_CURRENT_USER\Software\Remcos-ZHDGID
It connects to the following possibly malicious URL:
- {BLOCKED}.{BLOCKED}.97.155:2556
SOLUTION
9.800
16.490.05
21 Jan 2021
16.491.00
22 Jan 2021
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.XXPE50FFF040
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
Identify and terminate files detected as Backdoor.MSIL.REMCOS.JCASJZ
- 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 5
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\Remcos-ZHDGID
- exepath = {Hex value}
- exepath = {Hex value}
- In HKEY_CURRENT_USER\Software\Remcos-ZHDGID
- licence = 415CD5ADD079B4D70514510C06065D6B
- licence = 415CD5ADD079B4D70514510C06065D6B
Step 6
Delete this registry key
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
- Remcos-ZHDGID
- Remcos-ZHDGID
Step 7
Search and delete this file
- %Application Data%\remcos\logs.dat
Step 8
Search and delete this folder
- %Application Data%\remcos
Step 9
Scan your computer with your Trend Micro product to delete files detected as Backdoor.MSIL.REMCOS.JCASJZ. 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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