Analysis by: Jay Bradley Nebre
 PLATFORM:

Windows

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

  • Threat Type: Coinminer

  • Destructiveness: No

  • Encrypted:

  • 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 requires being executed with a specific argument/parameter, an additional component, or in a specific environment in order to proceed with its intended routine. It uses the system's central processing unit (CPU) and/or graphical processing unit (GPU) resources to mine cryptocurrency.

  TECHNICAL DETAILS

File Size: 2,823,168 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 29 Nov 2019
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:

  • {Malware Path}\wakacobs.exe
  • {Malware Path}\rakecobs.exe

It creates the following folders:

  • %Windows%\Swil
  • %System%\wostmp

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It injects codes into the following process(es):

  • wakacobs.exe
  • rakecobs.exe

Dropping Routine

This Coinminer drops the following files:

  • %Windows%\Swil\pro_logs
  • %System%\wostmp\{random numbers} - copy of original malware

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

This Coinminer requires being executed with a specific argument/parameter, an additional component, or in a specific environment in order to proceed with its intended routine.

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: 15.528.04
FIRST VSAPI PATTERN DATE: 29 Nov 2019
VSAPI OPR PATTERN File: 15.529.00
VSAPI OPR PATTERN Date: 30 Nov 2019

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.XXPE50FFF033

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 Coinminer.Win64.MALXMR.TIAOODCK

[ Learn More ]
  1. 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.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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.
  • %Windows%\Swil
  • %System%\wostmp

Step 6

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.
  • {Malware Path}\wakacobs.exe
  • {Malware Path}\rakecobs.exe

Step 7

Scan your computer with your Trend Micro product to delete files detected as Coinminer.Win64.MALXMR.TIAOODCK. 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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