Backdoor.Win32.REMCOS.USMANEAGFM

March 24, 2020
 Modified by: Paul Steven Nadera
 ALIASES:

Trojan:Win32/Occamy.C [non_writable_container] (Microsoft); a variant of Generik.BAMURYZ trojan (NOD32)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • 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

File Size:

996,903 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Mar 2020

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:

  • C:\h0592a4209

It drops the following files:

  • %System Root%\h0592a4209\tfngic.vbe
  • %System Root%\h0592a4209\bcinm.exe
  • %System Root%\h0592a4209\wohu.docx
  • %System Root%\h0592a4209\tunmjt.exe
  • %System Root%\h0592a4209\xuiap.msc
  • %System Root%\h0592a4209\sqmmkc.msc
  • %System Root%\h0592a4209\hwjakk.nls
  • %System Root%\h0592a4209\stxiddoto.dat
  • %System Root%\h0592a4209\cdtqu.bin
  • %System Root%\h0592a4209\fwmpdwvjhl.ppt
  • %System Root%\h0592a4209\uxqqafdp.xls
  • %System Root%\h0592a4209\nqenuo.txt
  • %System Root%\h0592a4209\ewgdiofgcw.exe
  • %System Root%\h0592a4209\olfbxdfii.pdf
  • %System Root%\h0592a4209\fpiie.jpg
  • %System Root%\h0592a4209\halqjt.txt
  • %System Root%\h0592a4209\amfqwhfvux.msc
  • %System Root%\h0592a4209\iaiwr.dll
  • %System Root%\h0592a4209\wojqxv.ppt
  • %System Root%\h0592a4209\trmogsjkkf.txt
  • %System Root%\h0592a4209\qjgp.dat
  • %System Root%\h0592a4209\gawiwnati.msc
  • %System Root%\h0592a4209\atgkmdtqdp.icm
  • %System Root%\h0592a4209\qbggwcdx.log
  • %System Root%\h0592a4209\ojbkpmtwd.exe
  • %System Root%\h0592a4209\kcxong.bin
  • %System Root%\h0592a4209\rrqgrvbskx.ico
  • %System Root%\h0592a4209\run.vbs
  • %User Temp%\RegSvcs.exe
  • %User Profile%\temp\xhnneaglln.cpl
  • %Appplication Data%\{GUID}\task.dat
  • %Appplication Data%\{GUID}\catalog.dat
  • %Appplication Data%\{GUID}\storage.dat
  • %Appplication Data%\{GUID}\settings.bin
  • %User Temp%\vggvszg1.gu3
  • %User Temp%\pyunns0r.pas
  • %User Temp%\hn43doze.kpj
  • %User Temp%\asweb2x5.izf

(Note: %System Root% is the Windows root folder, where it usually is C:\ 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).. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %User Temp%\RegSvcs.exe
  • "%System%\WScript.exe" "%System Root%\h0592a4209\run.vbs"
  • "%System Root%\h0592a4209\bcinm.exe" bfktrftlnk.ccs
  • "schtasks.exe" /create /f /tn "PCI Service" /xml "%User Temp%\tmp4C14.tmp"
  • "%Windows%\microsoft.net\framework\{version}\vbc.exe" /shtml "%User Temp%\vggvszg1.gu3"
  • "%Windows%\microsoft.net\framework\{version}\vbc.exe" /shtml "%User Temp%\pyunns0r.pas"
  • "%Windows%\microsoft.net\framework\{version}\vbc.exe" /shtml "%User Temp%\hn43doze.kpj"
  • "%Windows%\microsoft.net\framework\{version}\vbc.exe" /shtml "%User Temp%\asweb2x5.izf"

(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).. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Autostart Technique

This Backdoor modifies the following registry entries to ensure it automatic execution at every system startup:

HKLM\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows Update = "%System Root%\h0592a4209\bcinm.exe %System Root%\h0592a4209\bfktrftlnk.ccs"

Other Details

This Backdoor connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.24.183:54985
  • {BLOCKED}.{BLOCKED}.53.136:54985

It adds the following scheduled tasks:

  • Task Name: PCI Service
  • Action: Start Program "%User Temp%\RegSvcs.exe $(Arg0)"

(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).)

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.736.02

FIRST VSAPI PATTERN DATE:

11 Mar 2020

VSAPI OPR PATTERN File:

15.737.00

VSAPI OPR PATTERN Date:

12 Mar 2020

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.XXPE50FFF034

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

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry value

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Windows Update = "%System Root%\h0592a4209\bcinm.exe %System Root%\h0592a4209\bfktrftlnk.ccs"

Step 6

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:

  • PCI Service - "%User Temp%\RegSvcs.exe $(Arg0)"

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. If the strings match the list above, delete the task.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

Step 7

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\h0592a4209\

Step 8

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\RegSvcs.exe
  • %User Profile%\temp\xhnneaglln.cpl
  • %Appplication Data%\{GUID}\task.dat
  • %Appplication Data%\{GUID}\catalog.dat
  • %Appplication Data%\{GUID}\storage.dat
  • %Appplication Data%\{GUID}\settings.bin
  • %User Temp%\vggvszg1.gu3
  • %User Temp%\pyunns0r.pas
  • %User Temp%\hn43doze.kpj
  • %User Temp%\asweb2x5.izf

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.REMCOS.USMANEAGFM. 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.


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