Analysis by: Rheniel Rhay Ramos
ALIASES:

Win32/CoinMiner.BFC (ESET-NOD32); Trojan.Win32.Miner.tukr (Kaspersky);

 PLATFORM:

Windows

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

  • Threat Type: Coinminer

  • Destructiveness: No

  • Encrypted: No

  • 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.

It creates folders where it drops its files.

It uses the system's central processing unit (CPU) and/or graphical processing unit (GPU) resources to mine cryptocurrency.

  TECHNICAL DETAILS

File Size: 414,208 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 27 Feb 2018
Payload: Drops 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%\IXP000.TMP\TMP{random}.TMP -> deleted afterwards
  • %User Temp%\IXP000.TMP\audiodig.exe
  • %User Temp%\IXP000.TMP\audiodig
  • %User Temp%\IXP000.TMP\audiodig.reg
  • %System%\audiodig -> Miner config file
  • %System%\init.bat

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops and executes the following files:

  • %User Temp%\IXP000.TMP\init.bat -> used to copy the files from Temp to System32
  • %System%\audiodig.exe -> Miner
  • %System%\audiodig.reg -> used to add autostart registry

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This Coinminer adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
XMRRUN = "%System%\audiodig.exe -c %System%\audiodig"

Other System Modifications

This Coinminer adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
wextract_cleanup0 = "rundll32.exe %System%\advpack.dll,DelNodeRunDLL32 "%User Temp%\IXP000.TMP\""

Other Details

This Coinminer does the following:

  • It uses the following details for its mining capabilities:
    • url: {BLOCKED}l.{BLOCKED}s.in:8080
    • user: NewWorld
    • pass: 1
  • It deletes the following folder and all of its contents if it fails to copy them in the %System% directory:
    • %User Temp%\IXP000.TMP\

It uses the system's central processing unit (CPU) and/or graphical processing unit (GPU) resources to mine cryptocurrency. This behavior makes the system run abnormally slow.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.110.06
FIRST VSAPI PATTERN DATE: 05 Mar 2018
VSAPI OPR PATTERN File: 14.111.00
VSAPI OPR PATTERN Date: 06 Mar 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

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
    • XMRRUN = "%System%\audiodig.exe -c %System%\audiodig"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • wextract_cleanup0 = "rundll32.exe %System%\advpack.dll,DelNodeRunDLL32 "%User Temp%\IXP000.TMP\""

Step 5

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.
  • %User Temp%\IXP000.TMP\

Step 6

Search and delete these files

[ 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.
  • %System%\audiodig.exe
  • %System%\audiodig.reg
  • %System%\audiodig
  • %System%\init.bat

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as COINMINER_MALXMR.AB-WIN32. 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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